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All Trucks›Mack Pinnacle CXU›How to Fix It
Mack Pinnacle CXU · repair

How to Fix ItRemoval and replacement, start to finish. Everything from an oil change to a kingpin.

How these are written

Removal and replacement only — working out which part is bad lives on the codes page, and the numbers live on the torque page so there is one place to keep them right. When a step needs a figure, it names the fastener. Look it up rather than guessing.

Engine oil and filter change

Safety first

Hot oil burns. Park level, chock the wheels, and let the engine cool below 140 F before draining.

Labor time
0.8 hr · 0.5-1.0 hr typical; varies by drain time and filter access
Book time — actual time varies by shop and truck condition
Tools
Oil drain pan (55 qt), Torque wrench, 1/2 in drive, Filter wrench, Funnel, Clean rags
Parts
Oil filters and O-rings, drain plug seal ring, engine oil to the spec on the fluids page
  1. Warm the engine to operating temperature, shut it down, and let it sit 10 minutes so oil drains back out of the head.
  2. Remove the oil fill cap and pull the dipstick to vent the crankcase - without this it glugs and takes twice as long.
  3. Put the drain pan under the plug, then remove the plug with hand tools only. Never use an air ratchet on a drain plug.
  4. Let it drain fully. Look at the drained oil for coolant (milky), metal (glitter) or fuel (thin smell) - that is free diagnosis.
  5. Fit a new seal ring and reinstall the drain plug. Torque to the engine-specific value on the Bolt Tightness page.
  6. Replace the oil filter element(s) and O-rings. Lubricate the new O-rings with clean oil, never grease.
  7. Install the filter cap(s) and torque to the value on the Bolt Tightness page. Two-filter housings usually have two different values.
  8. Fill with the specified volume of the correct oil, start the engine, and idle 60 seconds to pressurise.
  9. Shut down, wait 10 minutes, and check the dipstick. Top off to the full mark - do not overfill.
  10. Run the engine and check the drain plug and filter housings for leaks before releasing the truck.

Fuel filter and water separator service

Safety first

Diesel is a skin irritant and a fire risk. No smoking and no hot work nearby.

Labor time
0.7 hr · 0.5-1.0 hr; add 0.5 hr if the system needs priming
Book time — actual time varies by shop and truck condition
Tools
Filter strap or band wrench, Drain container, Torque wrench, Clean rags
Parts
Primary filter/separator element, secondary filter element, O-rings
  1. Open the drain at the bottom of the separator and catch the water and fuel in a container.
  2. Close the drain once clean fuel runs - if water keeps coming, the tank has a water problem, not a filter problem.
  3. Remove the primary filter element or housing bowl.
  4. Lubricate the new seal and install it hand-tight plus whatever the filter maker specifies. Never over-tighten a spin-on.
  5. Replace the secondary filter element the same way.
  6. Cycle the key to run the lift pump and prime the system. Most modern engines self-prime; older ones need the hand primer.
  7. Start the engine and check for leaks under pressure.
  8. A water-in-fuel lamp that returns immediately after a filter change points at the sensor, not the fuel.

Serpentine belt and tensioner

Safety first

Engine off, key out, batteries disconnected before your hands go near the fan or pulleys.

Labor time
0.7 hr · 0.5-1.0 hr; add 0.5 hr if the tensioner is replaced
Book time — actual time varies by shop and truck condition
Tools
Belt routing tool or 1/2 in breaker bar, Belt wear gauge, Mirror and light
Parts
Serpentine belt, tensioner assembly, idler pulley if the bearing is noisy
  1. Photograph the belt routing before you touch anything. Every engine routes differently.
  2. Rotate the tensioner with the routing tool to release tension and slip the belt off.
  3. Inspect every pulley for play, roughness and glazing. Spin each idler by hand and listen.
  4. Check the tensioner pivot and confirm the wear indicator sits in the acceptable band.
  5. Route the new belt exactly per the diagram. Confirm it is seated in every groove - a belt one rib off fails within miles.
  6. Release the tensioner slowly and check the belt is centred on every pulley.
  7. Start the engine and watch the belt for 30 seconds for tracking and noise.

Valve adjustment (overhead set)

Safety first

Engine cold for the setting. Disconnect batteries so the engine cannot be cranked while your hands are inside.

Worth knowing

Lash settings differ by engine - DD15, MX-13, X15, D13, A26 and MP8 all publish their own intake/exhaust clearances and adjust differently (some use a dial indicator on the injector). Take the clearances from the OEM engine manual for your serial number, not from a forum.

Labor time
3.5 hr · 2.5-4.0 hr; both valve covers, full lash set
Book time — actual time varies by shop and truck condition
Tools
Feeler gauges, Valve adjusting wrench, Barring tool or socket for the crank, Torque wrench, New valve cover gaskets
Parts
Valve cover gasket(s), injector O-rings if disturbed
  1. Let the engine sit until it is cold to the touch - lash must be set cold unless the OEM says otherwise.
  2. Disconnect the batteries and remove the keys before opening anything.
  3. Remove the valve cover(s) and clean the sealing surface so old gasket material cannot fall into the head.
  4. Bar the engine to cylinder 1 top dead centre on the compression stroke, confirmed against the timing marks.
  5. Set the clearances on the cylinders listed for that position in the firing order, using the OEM spec.
  6. Bar the engine through one full revolution and set the remaining cylinders.
  7. Re-check every rocker you adjusted - a missed locknut is the classic failure here.
  8. Torque the locknuts to spec, fit new valve cover gaskets, and reinstall the covers.
  9. Reconnect the batteries, start the engine, and listen for a new tick that was not there before.

Fuel injector replacement

Safety first

High-pressure fuel. Release pressure before opening any line. Diesel on a hot manifold is a fire risk.

Worth knowing

New injectors carry a trim/calibration code that must be programmed into the ECM, or the engine will run rough and set codes. Have the laptop ready before you start.

Labor time
2.0 hr · 1.5-2.5 hr per injector; programming adds 0.5 hr
Book time — actual time varies by shop and truck condition
Tools
Injector puller, Torque wrench (in-lb and ft-lb), Torque angle gauge, Compressed air, Diagnostic laptop for the injector trim code
Parts
Remanufactured or new injector, hold-down hardware, O-rings, fuel line seals
  1. Read and record the fault codes and any cylinder balance data before disturbing anything.
  2. Release fuel pressure per the OEM procedure and disconnect the batteries.
  3. Clean the area around the injector thoroughly - dirt into the fuel gallery ruins the new injector.
  4. Remove the valve cover and disconnect the injector harness.
  5. Disconnect the high-pressure feed line and cap both ends immediately.
  6. Remove the hold-down bolt or clamp and pull the injector with the correct puller. Never lever on the body.
  7. Clean the bore, fit new O-rings and seals, and lubricate them with clean fuel.
  8. Seat the new injector, fit new hold-down hardware, and torque in stages to the OEM spec.
  9. Reconnect the high-pressure line and torque to spec, then the harness.
  10. Program the injector trim code with the diagnostic tool.
  11. Start the engine, check for fuel leaks at idle and under load, then clear the old codes and re-read.

Water pump replacement

Safety first

Drain coolant cold. Hot coolant under pressure will scald. Dispose of coolant properly - it is toxic.

Labor time
2.0 hr · 1.5-3.0 hr; add 1.0 hr if the fan clutch is removed for access
Book time — actual time varies by shop and truck condition
Tools
Coolant drain container, Torque wrench, Pulley puller, Gasket scraper
Parts
Water pump, gasket or O-ring, coolant, belt if contaminated
  1. Drain the cooling system into a clean container so you can measure how much comes out.
  2. Remove the belt and the fan or fan drive as needed for access.
  3. Disconnect the coolant hoses and the heater feed.
  4. Remove the pump mounting bolts in a crossing pattern and lift the pump away.
  5. Clean both mating surfaces until they are bare metal. Old gasket left behind is the number one cause of a repeat leak.
  6. Fit the new pump with a new gasket or O-ring - never reuse one.
  7. Torque the bolts in a crossing pattern to the OEM value on the Bolt Tightness page.
  8. Reconnect hoses, refill with the correct coolant, and bleed the system with the heater on full hot.
  9. Run to operating temperature with the cap on, then re-check the level cold the next morning.

Thermostat replacement

Safety first

Cold engine only. Drain enough coolant to get below the housing.

Labor time
1.0 hr · 0.5-1.5 hr; depends on housing access and refill/bleed
Book time — actual time varies by shop and truck condition
Tools
Coolant container, Torque wrench, Gasket scraper, Socket set
Parts
Thermostat, thermostat housing gasket or seal, coolant
  1. Drain coolant to below the thermostat housing.
  2. Note the thermostat orientation before removal - the bleed hole or jiggle pin must face the correct way.
  3. Remove the housing bolts and lift the housing off.
  4. Clean the sealing surfaces and check the housing for cracks or pitting.
  5. Fit the new thermostat in the same orientation, with a new seal.
  6. Torque the housing bolts evenly to spec.
  7. Refill and bleed the system, then run to operating temperature and confirm the upper hose gets hot.
  8. Watch for a temperature that climbs then drops sharply - that is a thermostat opening late.

Radiator removal and replacement

Safety first

The radiator and fan assembly is heavy and awkward. Support it before the last bolt comes out. Drain cold.

Labor time
4.0 hr · 3.0-5.0 hr; add 1.0 hr if transmission cooler lines are integrated
Book time — actual time varies by shop and truck condition
Tools
Coolant container, Hose clamp pliers, Torque wrench, Lifting equipment for the assembly, Fan wrench
Parts
Radiator, upper and lower hoses, clamps, coolant, mounting isolators if perished
  1. Drain the cooling system completely and dispose of the coolant properly.
  2. Remove the charge air cooler pipes and the upper and lower radiator hoses.
  3. Disconnect the fan shroud and move it clear. Note any overflow bottle or surge tank plumbing.
  4. Disconnect the transmission cooler lines if the radiator has an integrated cooler - cap them immediately.
  5. Support the radiator assembly and remove the mounting bolts and isolators.
  6. Lift the radiator out without letting it hang on the core. A lifted core is a leaking core.
  7. Transfer any brackets, sensors or the fan shroud to the new radiator.
  8. Set the new radiator on fresh isolators and torque the mounts to spec.
  9. Reconnect hoses with new clamps, the cooler lines, and the shrouding.
  10. Refill with the correct coolant, bleed with the heater on hot, and pressure-test before releasing the truck.

Charge air cooler leak test and replacement

Safety first

Pressurised air. Never exceed the test pressure on the label and never put your face near a boot under pressure.

Labor time
2.0 hr · 1.5-3.0 hr; pressure test adds 0.5 hr
Book time — actual time varies by shop and truck condition
Tools
Pressure test kit, Soap solution spray, Hose clamp pliers, Torque wrench
Parts
Charge air cooler, boots, clamps, mounting isolators
  1. Inspect all the boots and clamps first - most boost leaks are a split boot, not a holed cooler.
  2. Pressure the system to the OEM test pressure and spray soap solution on every joint.
  3. Bubbles at a clamp mean re-seat the boot. Bubbles from the core means replace the cooler.
  4. To remove, disconnect both boots and any mounting brackets.
  5. Support the cooler and remove the isolators - they are usually perished and should be replaced anyway.
  6. Clean the tube ends and fit new boots and clamps.
  7. Torque the clamps evenly. Overtightening cuts the boot and creates the leak you were fixing.
  8. Re-pressure-test and confirm no bubbles anywhere before reassembly.

Fan clutch and fan hub replacement

Safety first

The fan nut is often left-hand thread and very tight. Brace the pulley properly - a spinning fan blade cuts.

Labor time
1.5 hr · 1.0-2.0 hr; add 0.5 hr if the fan blade needs removal
Book time — actual time varies by shop and truck condition
Tools
Fan wrench set, Torque wrench, Pulley holder, Air hammer for stubborn nuts, Lifting aid
Parts
Fan clutch, fan hub bearing if worn, mounting hardware, fan blade if cracked
  1. Disconnect the batteries and remove the key.
  2. Remove the fan shroud and unbolt the fan blade from the clutch.
  3. Inspect the blades for cracks at the root - any crack means replace, not repair.
  4. Hold the pulley with the correct holder and release the fan clutch nut. Check the thread direction first.
  5. Remove the clutch and inspect the hub bearing for play and roughness.
  6. Fit the new clutch and torque the nut to the OEM specification.
  7. Refit the fan blade with new hardware and torque evenly.
  8. Reconnect any air or electrical control line to the clutch.
  9. Refit the shroud, start the engine, and confirm the fan engages when the coolant reaches the fan-on temperature.

Turbocharger removal and replacement

Safety first

Hot exhaust and oil. Let the engine cool fully. Oil in the exhaust can ignite - clean up spills.

Labor time
3.0 hr · 2.0-4.0 hr; add 1.0 hr for oil line replacement and prime
Book time — actual time varies by shop and truck condition
Tools
Torque wrench, Oil line wrenches, New gaskets and studs, Drain container, Cleaning solvent
Parts
Turbocharger, oil feed and drain gaskets, exhaust gaskets, studs and nuts, oil
  1. Let the engine cool completely and disconnect the batteries.
  2. Remove the air intake piping and the exhaust connections at the turbine.
  3. Cap the openings so nothing falls into the intake or exhaust.
  4. Disconnect and cap the oil feed line at the top and the oil drain at the bottom.
  5. Remove the mounting nuts or bolts and lift the turbo out. Note the orientation of the actuator.
  6. Clean both mating flanges flat. Old gasket left behind causes leaks and boost loss.
  7. Pre-lubricate the new turbo at the oil inlet with clean engine oil - a dry start destroys the bearings.
  8. Fit new gaskets and studs, set the turbo in place, and torque the mounts in stages.
  9. Reconnect the oil drain first, then the feed line, then the exhaust and intake.
  10. Prime the oil system by cranking with fuel disabled until pressure shows, then start.
  11. Run at idle for two minutes before load, then check for oil and exhaust leaks.

EGR cooler replacement

Safety first

Drain coolant cold. The EGR cooler holds coolant and exhaust gas - both are hot after running.

Labor time
3.5 hr · 2.5-4.5 hr; coolant drain and refill included
Book time — actual time varies by shop and truck condition
Tools
Coolant container, Torque wrench, Gasket scraper, Hose clamp pliers
Parts
EGR cooler, gaskets, coolant, hoses if hardened
  1. Drain the cooling system below the cooler level.
  2. Disconnect the EGR gas tubes at both ends and cap them.
  3. Disconnect the coolant hoses and the mounting brackets.
  4. Remove the cooler and inspect the old one for cracks and coolant staining, which confirms the diagnosis.
  5. Clean all mating surfaces flat.
  6. Fit the new cooler with new gaskets, and torque the mounts and tube flanges to spec.
  7. Reconnect coolant hoses and refill with the correct coolant.
  8. Bleed the cooling system with the heater on hot, run to temperature, and check for both coolant and exhaust leaks.

Engine mount replacement

Safety first

Support the engine weight before removing a mount. Never work under a load held only by a jack.

Labor time
1.5 hr · 1.0-2.0 hr per mount; engine must be supported
Book time — actual time varies by shop and truck condition
Tools
Jack and wood block, Torque wrench, Pry bar, Socket set
Parts
Engine mount isolator(s), mounting bolts if corroded
  1. Disconnect the batteries.
  2. Support the engine at the oil pan with a wood block to spread the load - never metal on aluminium.
  3. Take the weight slightly off the mount, do not lift the engine more than needed.
  4. Remove the mount bolts and lift the old isolator out.
  5. Inspect the frame bracket for cracks and elongation at the bolt holes.
  6. Fit the new isolator and start the bolts by hand.
  7. Lower the engine onto the mount, then torque to the OEM spec with the weight settled.
  8. Remove the support, start the engine, and check for a new vibration or clunk under load.

Clutch replacement (manual transmission)

Safety first

A transmission is 600-800 lb. Use a rated jack and a second person. Never support it on your chest.

Worth knowing

Automated manual transmissions (DT12, TX-12, mDRIVE, I-Shift, Endurant) use a self-adjusting clutch with an electronic release system. Follow the OEM procedure for clutch wear calibration - do not treat them like a manual.

Labor time
8.0 hr · 6.0-10.0 hr; transmission out; add 2.0 hr for flywheel resurface
Book time — actual time varies by shop and truck condition
Tools
Transmission jack, Clutch alignment tool, Flywheel resurfacing or new flywheel, Torque wrench to 300 ft-lb, Dial indicator
Parts
Clutch disc, pressure plate, release bearing, pilot bearing, flywheel bolts, bell housing gaskets
  1. Disconnect the batteries and drain the air system.
  2. Remove the driveshaft and support it out of the way.
  3. Disconnect the clutch linkage, air lines and any electrical harness from the transmission.
  4. Support the transmission with a rated jack and remove the bell housing bolts.
  5. Slide the transmission back and lower it clear.
  6. Inspect the flywheel for cracks, heat checking and worn ring gear. Measure it rather than eyeballing it.
  7. Remove the pressure plate and disc. Note which way the disc faces - it is easy to fit backwards.
  8. Replace the pilot bearing and the release bearing as a set.
  9. Clean the flywheel face and check runout with a dial indicator.
  10. Fit the disc with the alignment tool, then the pressure plate. Torque the bolts in a crossing pattern in stages.
  11. Install the release bearing and check the fork or actuator travel.
  12. Reinstall the transmission, torque the bell housing bolts, and reconnect everything you disconnected.
  13. Refill the transmission to the correct level with the specified oil.
  14. Road test and check the clutch engages smoothly with no chatter.

Transmission oil and filter service

Safety first

Warm oil drains better but burns. Wear gloves and eye protection.

Labor time
1.5 hr · 1.0-2.0 hr; add 0.5 hr if the pan comes off
Book time — actual time varies by shop and truck condition
Tools
Drain pan, Pump or filler, Torque wrench, Filter wrench
Parts
Transmission oil to the OEM spec, filter kit, pan gasket, drain plug washer
  1. Drive the truck to warm the oil, then park level and shut down.
  2. Clean around the fill and drain plugs before opening anything.
  3. Remove the fill plug first - if you drain it and then cannot get the fill plug out, you are stuck.
  4. Drain into a measured container and compare the volume to the spec.
  5. Look at the oil for metal glitter, clutch material or water.
  6. Replace the filter and the pan gasket if the pan comes off.
  7. Reinstall the drain plug with a new washer and torque to spec.
  8. Fill to the correct level with the specified oil, using the fill plug level or dipstick.
  9. Run through the gears and re-check the level.

Driveshaft and U-joint replacement

Safety first

Chock the wheels and release the parking brake only after the shaft is supported. A dropped shaft is heavy.

Worth knowing

Mark the shaft to the yoke before removal. Driveshafts are balanced as an assembly and refitting 180 degrees out creates a vibration that feels like a bad tyre.

Labor time
1.5 hr · 1.0-2.0 hr; add 0.5 hr per additional joint
Book time — actual time varies by shop and truck condition
Tools
U-joint press or sockets and hammer, Torque wrench, Snap ring pliers, Paint pen, Dial indicator for runout
Parts
U-joint kit, snap rings, centre bearing if equipped, new bolts
  1. Chock the wheels and mark the shaft-to-yoke alignment with a paint pen.
  2. Remove the bolts or straps at both ends and support the shaft.
  3. Lower the shaft out and inspect the slip yoke splines for wear.
  4. Press out the old U-joint caps and remove the cross.
  5. Clean the yoke bores and check for cracks or out-of-round.
  6. Press the new joint in, seating each cap evenly so the needle bearings do not fall over.
  7. Fit new snap rings and confirm the joint moves freely by hand with no tight spot.
  8. Reinstall the shaft in the original orientation, aligning your marks.
  9. Torque the bolts to spec and check runout if a vibration was the original complaint.

Driveshaft carrier bearing replacement

Safety first

Support the shaft. Do not let it hang on the transmission output seal.

Labor time
1.5 hr · 1.0-2.0 hr; shaft must be separated and supported
Book time — actual time varies by shop and truck condition
Tools
Bearing puller, Press, Torque wrench, Jack stands
Parts
Carrier bearing and rubber cushion, mounting hardware
  1. Mark the shaft alignment and support the driveshaft.
  2. Remove the bolts holding the carrier bracket to the frame crossmember.
  3. Separate the shaft sections if the bearing is between them.
  4. Pull the old bearing off with a puller, never by hammering on the shaft.
  5. Clean and inspect the shaft surface for wear under the bearing.
  6. Press the new bearing on squarely, applying force on the inner race only.
  7. Reinstall the bracket with new hardware and set the preload or shim stack per the OEM spec.
  8. Check the shaft angle and runout, then torque the bolts.

Differential oil change

Safety first

Warm gear oil smells strong and burns. Ventilate the shop.

Labor time
0.8 hr · 0.5-1.0 hr; add 1.0 hr if cover comes off for inspection
Book time — actual time varies by shop and truck condition
Tools
Drain pan, Suction gun or pump, Torque wrench, New gasket or sealant
Parts
Gear oil to the OEM spec, drain and fill plug washers, cover gasket if fitted
  1. Drive to warm the oil, then park level.
  2. Clean around the fill plug and remove the fill plug first.
  3. Remove the drain plug and drain into a measured container.
  4. Inspect the drained oil for metal, and check the magnetic plug for heavy fuzz - fuzz is normal, chips are not.
  5. Clean the plugs and fit new washers.
  6. Reinstall the drain plug and torque to spec.
  7. Fill until oil runs out of the fill hole (fill-to-level axles) or to the specified volume.
  8. Torque the fill plug and check for leaks after a short drive.

Wheel seal and bearing replacement

Safety first

A loaded wheel assembly is 150+ lb. Use a dolly. Never let a hub hang on the spindle - it cocks the seal and it will leak.

Worth knowing

ConMet PreSet hubs are pre-adjusted: torque the spindle nut and do not back it off. Conventional hubs need the TMC RP618 adjustment sequence. Check which one you have before you touch the nut.

Labor time
3.0 hr · 2.0-4.0 hr per wheel end; add 1.0 hr if bearings are replaced
Book time — actual time varies by shop and truck condition
Tools
Wheel dolly, Seal driver, Torque wrench to 500 ft-lb, Snap ring pliers, Dial indicator, Bearing packer or gear oil
Parts
Wheel seal, bearing cones and cups if worn, hub gasket, hub cap gasket, oil or grease to spec
  1. Chock the wheels, cage the spring brakes on the axle being worked, and lift the axle onto stands. Releasing the parking brake does NOT release a spring brake - only caging does.
  2. Remove the wheel nuts and lift the tyre and wheel off.
  3. Remove the hub cap or the axle shaft on a drive axle, catching the oil.
  4. Remove the spindle nut locking device and the adjusting nut.
  5. Slide the hub and drum off the spindle squarely. Support its weight.
  6. Inspect the spindle for scoring and the bearing cups for pitting or blueing. Replace bearings as a set if worn.
  7. Clean the hub and spindle thoroughly and dry them - solvent left behind dilutes the new oil.
  8. Drive the new seal in square and flush. A cocked seal leaks immediately.
  9. Pack or oil the bearings per the OEM, then fit the hub.
  10. Torque the spindle nut per the hub type and set end play to 0.001-0.005 in with a dial indicator.
  11. Fit the locking device, hub cap with a new gasket, and refill the hub to the correct level.
  12. Refit the wheel, torque the nuts in a star pattern to 450-500 ft-lb, and re-check after 50-100 miles.

Service / spring brake chamber replacement

Safety first

A spring brake contains a compressed spring that can kill you. Cage it before removal and never open the clamp band. Block the wheels and drain all air first.

Labor time
1.0 hr · 0.5-1.5 hr; caging and stroke check included
Book time — actual time varies by shop and truck condition
Tools
Impact wrench, 3/4 in, Torque wrench to 200 ft-lb, Caging bolt, Pry bar
Parts
Replacement chamber with new mounting hardware, clevis pins, cotter pins
  1. Chock the wheels, drain all air at the tanks, and confirm zero pressure at the chamber.
  2. Disconnect the air hose. Cap the line to keep dirt out.
  3. Disconnect the push rod clevis from the slack adjuster - cotter pin, then clevis pin.
  4. Remove the two mounting nuts and washers, then remove the chamber. Confirm it is caged first.
  5. Clean the bracket surface. It must be flat and free of burrs - never shim a chamber.
  6. Install the new chamber with the new self-locking nuts. Alternate top and bottom and bring them up in steps to 133 +/- 7 ft-lb (180 +/- 10 Nm).
  7. Set the push rod into the clevis and install the clevis pin and a new cotter pin. Bend the cotter ears.
  8. Align the slack adjuster so the angle to the push rod is greater than 90 degrees in the caged position.
  9. Reconnect the air line, recharge, and check for leaks with soap solution.
  10. Release the parking brake and confirm push rod stroke is within the CVSA out-of-service limit.

Air dryer desiccant cartridge

Safety first

Wear eye protection. Drain all air pressure from the system before opening the dryer.

Labor time
0.5 hr · 0.3-0.7 hr; simple swap if the housing is clean
Book time — actual time varies by shop and truck condition
Tools
Strap wrench, Clean rags, Torque wrench
Parts
Desiccant cartridge kit, purge valve kit if contaminated
  1. Drain the air system completely at the tanks.
  2. Remove the cartridge with a strap wrench - never a chisel or hammer.
  3. Inspect the old cartridge and the housing for oil. Oil carryover means the compressor is passing oil, and a new cartridge will fail again.
  4. Clean the sealing surface on the housing.
  5. Lubricate the new cartridge seal with the grease in the kit.
  6. Thread the cartridge on by hand, then torque it to the cartridge maker's spec.
  7. Recharge the system and confirm the dryer purges and the governor cuts out at the correct pressure.

Automatic slack adjuster replacement

Safety first

Block the wheels, drain the air, and cage the spring brake before removing the push rod connection.

Labor time
1.0 hr · 0.5-1.5 hr; stroke measurement after install
Book time — actual time varies by shop and truck condition
Tools
Pry bar, Torque wrench, Snap ring pliers, Grease gun
Parts
Slack adjuster, clevis pins, washers, cotter pins, seals
  1. Chock the wheels and drain the air system.
  2. Measure and record the current push rod stroke before disassembly - it tells you whether the adjuster or the foundation brake is the problem.
  3. Disconnect the push rod clevis and remove the clevis pin.
  4. Remove the snap ring or retaining washer from the cam shaft and slide the adjuster off.
  5. Inspect the cam shaft splines and the S-cam bushings for wear. A worn bushing makes a new adjuster over-stroke.
  6. Clean the splines and fit the new adjuster, lining up the alignment marks.
  7. Fit a new snap ring and reconnect the clevis with new pins and cotter pins.
  8. Grease the adjuster fitting.
  9. Recharge the air, apply the brakes several times to let the adjuster set itself, then measure stroke again.
  10. Confirm the stroke is inside the CVSA limit for the chamber size.

Brake shoe and drum replacement

Safety first

Brake dust may contain harmful fibres. Do not blow it out with compressed air - use a damp cloth or a vacuum with a HEPA filter.

Labor time
3.0 hr · 2.0-4.0 hr per axle; add 1.0 hr if drums are replaced
Book time — actual time varies by shop and truck condition
Tools
Brake spring pliers, Drum dolly, Torque wrench, Brake spoon, Micrometer or drum gauge
Parts
Brake shoes, springs and hardware kit, drums if worn past spec, cam bushings if loose
  1. Chock the wheels, drain the air, and cage the spring brakes on the axle you are working.
  2. Back the slack adjuster off fully so the shoes retract.
  3. Remove the wheel and drum. If the drum is tight, back the adjuster further rather than forcing it.
  4. Remove the return springs and the shoe retaining hardware, keeping track of which spring goes where.
  5. Lift the shoes off the anchor pins and the S-cam rollers.
  6. Inspect the S-cam, anchor pins and bushings. Replace anything worn - new shoes on worn bushings wear unevenly.
  7. Clean the backing plate with a damp cloth, not compressed air.
  8. Check the drum for cracks, heat checking and score depth, and measure it against the maximum diameter.
  9. Fit new shoes with new hardware and springs, seating the rollers on the cam.
  10. Refit the drum and wheel, torque the wheel nuts in a star pattern.
  11. Adjust the slack adjuster and confirm the stroke is within spec.
  12. Road test and re-check adjustment after the first stop.

Air compressor replacement

Safety first

Drain the air system and the coolant cold. The discharge line gets hot enough to burn.

Labor time
3.0 hr · 2.0-4.0 hr; coolant and air lines disconnected
Book time — actual time varies by shop and truck condition
Tools
Coolant container, Torque wrench, Line wrenches, Gasket scraper
Parts
Air compressor, gaskets, coolant hoses, discharge line if cracked, coolant
  1. Drain all air pressure and drain coolant below the compressor level.
  2. Disconnect the discharge line at the compressor and the dryer end, and inspect it for carbon build-up.
  3. Disconnect the coolant supply and return hoses and the intake.
  4. Remove the mounting bolts and lift the compressor off.
  5. Clean the mounting flange and check the drive gear or coupling for wear.
  6. Fit the new compressor with new gaskets, torque the mounts to spec.
  7. Reconnect the coolant hoses, the intake, and the discharge line with new seals.
  8. Refill coolant and bleed the system.
  9. Run the engine and build air, watching the build-up time and the governor cut-out pressure.

ABS wheel speed sensor replacement

Safety first

Block the wheels. Do not pull the sensor by its cable.

Labor time
0.7 hr · 0.5-1.0 hr; add 0.5 hr if the harness is chafed
Book time — actual time varies by shop and truck condition
Tools
Diagnostic tool, Multimeter, Socket set, Wire brush
Parts
Wheel speed sensor, sensor clip or bushing, grease
  1. Read the ABS codes first and note which wheel position is flagged.
  2. Inspect the harness at that wheel for chafing before condemning the sensor - chafed harness causes most ABS faults.
  3. Identify the sensor type first. A passive (inductive) sensor is checked by resistance and should read 900-2000 ohms; an active (Hall-effect) sensor has no meaningful resistance and must be checked for supply voltage, ground and a switching signal while the wheel turns.
  4. Remove the sensor retaining bolt or clip and pull the sensor straight out.
  5. Clean the mounting bore so the new sensor seats fully - a sensor that does not seat reads wrong.
  6. Apply the specified grease to the new sensor and fit it.
  7. Reconnect and route the harness away from moving parts.
  8. Drive the truck above the ABS self-test speed and confirm the light goes out and no codes return.

Air spring (airbag) replacement

Safety first

Drain the air suspension completely. A pressurised bag can release violently. Support the axle before removing a bag.

Labor time
1.0 hr · 0.5-1.5 hr; per bag; air drained first
Book time — actual time varies by shop and truck condition
Tools
Jack and stands, Torque wrench, Air line wrench, Soap solution
Parts
Air spring, mounting hardware, air line fitting
  1. Raise the frame and support it on stands so the suspension hangs free.
  2. Drain all air from the suspension system at the leveling valve or the tank.
  3. Disconnect the air line at the top fitting and cap it.
  4. Remove the upper and lower mounting bolts or nuts.
  5. Compress the old bag and remove it.
  6. Inspect the mounting surfaces for cracks and the air line for brittleness.
  7. Seat the new bag with the alignment pins in the correct holes - a bag fitted 90 degrees out rubs and fails.
  8. Torque the mounting hardware to spec.
  9. Reconnect the air line, recharge, and check the fitting with soap solution.
  10. Verify the ride height is correct on both sides.

Shock absorber replacement

Safety first

Support the frame, not the axle, when the shock is removed.

Worth knowing

Replace shocks in axle pairs. One new shock beside a worn one makes the axle behave unpredictably under load.

Labor time
1.0 hr · 0.5-1.5 hr; per shock; replace in pairs
Book time — actual time varies by shop and truck condition
Tools
Torque wrench, Socket and wrench set, Jack and stands, Pry bar
Parts
Shock absorbers (fit in pairs per axle), mounting bolts and bushings
  1. Support the frame so the suspension is at normal ride height.
  2. Inspect the old shocks for oil weeping, which is the usual sign of failure.
  3. Hold the shaft to stop it spinning and remove the upper nut.
  4. Remove the lower mounting bolt and pull the shock out.
  5. Check the mounting brackets for cracks and the bushings for wear.
  6. Fit the new shock with new bushings and hardware.
  7. Torque the mounts with the suspension at ride height, not hanging.
  8. Repeat on the other side of the axle before lowering the truck.
  9. Road test and check for a new clunk or a changed ride.

Leaf spring and U-bolt replacement

Safety first

A loaded leaf spring stores a lot of energy. Support the axle and the frame independently before removing U-bolts.

Labor time
2.5 hr · 1.5-3.5 hr; per spring; axle supported, U-bolts new
Book time — actual time varies by shop and truck condition
Tools
Heavy jack and stands, Torque wrench to 600 ft-lb, Impact wrench, Pry bar, New centre bolts
Parts
Leaf spring, U-bolts and high nuts, centre bolt, spring bushings, shackle pins if worn
  1. Support the frame on stands and the axle on a jack, with the weight off the spring.
  2. Soak the U-bolt nuts with penetrant - they are often rusted solid.
  3. Remove the U-bolt high nuts. Use a staged sequence: hand-tight, 60 ft-lb, 200 ft-lb, then final.
  4. Lower the axle enough to release the spring, then remove the spring eye pins or shackles.
  5. Inspect the hanger brackets and bushings. Worn bushings cause the same clunk as a cracked spring.
  6. Fit the new spring with a new centre bolt, aligning it with the axle seat hole.
  7. Install new U-bolts - never reuse old ones, they stretch.
  8. Tighten in stages to 180-230 ft-lb for 5/8 in, 270-330 for 3/4 in, 420-500 for 7/8 in, 520-600 for 1 in.
  9. Re-check the U-bolt torque with the truck at ride height, under load.
  10. Check axle alignment and ride height before releasing.

Torque rod and bushing replacement

Safety first

Support the axle so the rod is not under load when the bolts come out.

Labor time
1.5 hr · 1.0-2.0 hr; per rod; axle alignment check after
Book time — actual time varies by shop and truck condition
Tools
Torque wrench to 600 ft-lb, Press or bushing driver, Impact wrench, Pry bar
Parts
Torque rod, bushings, new mounting bolts
  1. Support the frame and axle so the suspension is unloaded.
  2. Pry-test the rod ends for movement - any visible play means replace.
  3. Mark the rod orientation and note which end goes to the frame.
  4. Remove the mounting bolts at both ends and lift the rod out.
  5. Inspect the frame and axle brackets for elongated holes and cracks.
  6. Press in new bushings square, applying force to the outer shell only.
  7. Fit the rod in the original orientation with new bolts.
  8. Torque the bolts to spec with the suspension at ride height.
  9. Check axle alignment - a mis-set lateral rod makes the truck dog-track.

Kingpin replacement

Safety first

The steering knuckle is heavy and hot-work may be involved. Support the axle on stands rated for the load.

Worth knowing

Kingpin work needs a reamer and a press. If you do not have both, this is a shop job - a poorly reamed bushing will seize or knock within a few thousand miles.

Labor time
4.5 hr · 3.0-6.0 hr; reamer and press required — shop job
Book time — actual time varies by shop and truck condition
Tools
Kingpin press set, Torque wrench to 600 ft-lb, Reamer, Dial indicator, Heavy jack
Parts
Kingpin kit with bushings and bearings, shims, seal, grease
  1. Lift the axle and support it on stands. Remove the wheel and the brake drum or caliper.
  2. Disconnect the tie rod end and the drag link from the knuckle.
  3. Drive out the kingpin lock pin and its retaining hardware.
  4. Press the old kingpin out from the top.
  5. Remove the knuckle and press out the old bushings.
  6. Clean the bore and press in the new bushings.
  7. Ream the bushings to fit the new pin, checking the fit with the pin dry.
  8. Fit the new pin with the thrust bearing and shims, set the vertical end play per spec.
  9. Install the lock pin with a new one, torque to spec.
  10. Grease thoroughly, reconnect the steering links, and check the wheel turns freely with no play.
  11. Check toe-in and set it before release.

Steering gear replacement

Safety first

Steering is safety-critical. Disconnect the batteries and drain the hydraulic system first.

Labor time
3.0 hr · 2.0-4.0 hr; pitman arm pull and bleed included
Book time — actual time varies by shop and truck condition
Tools
Pitman arm puller, Torque wrench to 400 ft-lb, Line wrenches, Fluid container
Parts
Steering gear, pitman arm nut, hydraulic line seals, power steering fluid
  1. Disconnect the batteries.
  2. Drain the power steering reservoir and disconnect the pressure and return lines. Cap them.
  3. Mark the pitman arm to the sector shaft before removal - it only fits one way and getting it wrong ruins the steering geometry.
  4. Remove the pitman arm nut and pull the arm with a puller.
  5. Remove the frame mounting bolts and lift the gear out.
  6. Transfer any brackets to the new gear and check the frame for cracks at the bolt holes.
  7. Fit the new gear and torque the mounting bolts to spec.
  8. Refit the pitman arm aligned to your marks and torque the nut.
  9. Reconnect the hydraulic lines with new seals.
  10. Fill the reservoir, run the engine, and bleed by turning lock to lock several times with the wheels off the ground.
  11. Top up the fluid, then check for leaks and confirm the steering returns to centre smoothly.

Alternator replacement

Safety first

Disconnect the battery ground first. The B+ terminal is live and unfused - a dropped wrench welds itself to the frame.

Labor time
1.5 hr · 1.0-2.0 hr; belt and belt guard removal included
Book time — actual time varies by shop and truck condition
Tools
Socket set, Torque wrench, Belt tool, Multimeter
Parts
Alternator, belt if worn, mounting hardware, terminal nuts
  1. Disconnect the negative battery cables and wait a minute for the modules to sleep.
  2. Record the charging voltage at the battery before removal, so you know what you are fixing.
  3. Release the belt tension and slip the belt off.
  4. Remove the B+ cable nut and the regulator connector.
  5. Remove the mounting bolts and lift the alternator out.
  6. Check the pulley and belt alignment on the new unit, and spin it by hand.
  7. Fit the new alternator, torque the mounts, reconnect B+ and the connector.
  8. Refit the belt to the correct routing.
  9. Reconnect the batteries, start, and confirm 13.8-14.6 V at the battery at fast idle.

Starter replacement

Safety first

Disconnect the battery ground first. The main stud carries several hundred amps - remove the ground before touching it.

Labor time
1.5 hr · 1.0-2.5 hr; heat shield removal adds time
Book time — actual time varies by shop and truck condition
Tools
Socket set, Torque wrench, Heat shield tools, Multimeter
Parts
Starter, mounting bolts, new terminal hardware
  1. Disconnect the battery ground cables.
  2. Remove any heat shield covering the starter - many Class 8 starters are buried behind one.
  3. Disconnect the control wire and the main B+ stud nut. Keep the nut and washer.
  4. Remove the mounting bolts and lower the starter out. It is heavier than it looks.
  5. Inspect the flywheel ring gear through the starter hole for missing or chewed teeth.
  6. Clean the bell housing mating surface so the new starter seats flat.
  7. Fit the new starter, torque the mounts, then reconnect B+ and the control wire.
  8. Reconnect the batteries and crank. If it spins without engaging, check the ring gear before blaming the starter.

Battery cable and terminal service

Safety first

Remove the ground first and refit it last. Rings and metal watch straps off - a shorted battery can melt them.

Labor time
1.0 hr · 0.5-1.5 hr; voltage drop test included
Book time — actual time varies by shop and truck condition
Tools
Wire brush, Terminal puller, Torque wrench, Multimeter, Heat shrink
Parts
Cables as needed, terminals, boots, anti-corrosion spray
  1. Disconnect the ground cables first, then the positives.
  2. Inspect every cable end for green corrosion, which wicks up inside the insulation.
  3. Measure voltage drop from battery to starter under crank load - more than 0.5 V means a bad cable.
  4. Clean terminals and posts to bare metal with a wire brush.
  5. Replace any cable that is swollen, stiff or corroded under the insulation.
  6. Refit in reverse order: positives first, grounds last.
  7. Torque the terminal nuts to spec - snug plus a quarter turn, do not crush a lead post.
  8. Spray anti-corrosion on the finished terminals.
  9. Confirm charging voltage and crank speed have improved.

Instrument cluster removal and replacement

Safety first

Disconnect the batteries and wait for the modules to sleep before unplugging the cluster, or you can set communication codes.

Worth knowing

A replacement cluster usually needs the odometer and configuration programmed to the VIN. A used cluster carries the donor truck's mileage - that is a legal problem, not just a technical one.

Labor time
2.0 hr · 1.0-3.0 hr; programming adds 0.5 hr
Book time — actual time varies by shop and truck condition
Tools
Trim panel tools, Torx and hex drivers, Torque screwdriver, Diagnostic tool
Parts
Replacement cluster, dash bezel clips if broken
  1. Disconnect the batteries and let the truck sit a few minutes so the network goes to sleep.
  2. Remove the trim bezel around the cluster. Work the clips with a proper trim tool, not a screwdriver.
  3. Remove the cluster mounting screws and note their lengths - they are usually different.
  4. Pull the cluster forward gently and release the connector locks before pulling the plugs.
  5. Inspect the connectors for corroded or pushed-back pins, which mimic a failed cluster.
  6. Fit the replacement and connect the plugs until they click.
  7. Reconnect the batteries and power up.
  8. Use the diagnostic tool to program the VIN configuration and odometer if required.
  9. Check every gauge and warning lamp, including the odometer and hour meter.

Headlamp assembly and bulb replacement

Safety first

Halogen bulbs are under pressure and get hot. Do not touch the glass with bare fingers - the oil shortens bulb life.

Labor time
1.0 hr · 0.5-1.5 hr; aiming adds 0.3 hr
Book time — actual time varies by shop and truck condition
Tools
Screwdriver set, Torque screwdriver, Multimeter, Aiming screen or wall
Parts
Headlamp assembly or bulb, seal, mounting hardware
  1. Disconnect the batteries or pull the lighting fuse.
  2. Remove the trim or the grille section that covers the lamp fasteners.
  3. Remove the mounting bolts and ease the assembly out.
  4. Disconnect the harness plug and inspect for corrosion.
  5. If only the bulb failed, fit the new one without touching the glass and check the seal.
  6. If the assembly is being replaced, transfer any brackets and fit a new gasket.
  7. Reconnect, refit, and align the aim against a wall at the specified distance.
  8. Confirm both low and high beam work and the turn signal is not hyper-flashing.

Mirror and mirror bracket replacement

Safety first

Have a second person hold the assembly - a mirror head and arm is awkward and easily dropped onto the door.

Labor time
1.0 hr · 0.5-1.5 hr; seal the door holes
Book time — actual time varies by shop and truck condition
Tools
Socket set, Torque wrench, Trim tools, Sealant
Parts
Mirror head or complete assembly, bracket, hardware, sealant for the door holes
  1. Support the mirror head before loosening anything.
  2. Disconnect the electrical plug for heat and power adjust if fitted.
  3. Remove the bracket bolts, working from the top down.
  4. Lift the old assembly clear and check the door skin for cracks or elongated holes.
  5. Clean the mounting area and apply sealant around the holes so water cannot get into the door.
  6. Fit the new bracket and start all the bolts by hand before tightening any.
  7. Torque the bolts evenly so the bracket does not distort.
  8. Reconnect the electrical plug and test heat and adjustment.
  9. Check the mirror is square and the view matches the other side.

Wiper motor and linkage replacement

Safety first

Mark the park position before removal or the blades will stop in the middle of the screen.

Labor time
1.5 hr · 1.0-2.5 hr; cowl and park position set-up
Book time — actual time varies by shop and truck condition
Tools
Socket set, Torque screwdriver, Trim tools, Puller for the wiper arms
Parts
Wiper motor, linkage if worn, wiper arms if the splines are stripped
  1. Disconnect the batteries.
  2. Run the wipers to the park position and switch off - photograph where the arms sit.
  3. Pry off the wiper arm caps, remove the nuts, and pull the arms with a puller.
  4. Remove the cowl panel or the access cover.
  5. Disconnect the linkage from the motor crank and the electrical plug.
  6. Remove the motor mounting bolts and lift it out.
  7. Fit the new motor and set the crank to the park position before connecting the linkage.
  8. Reconnect the linkage and the plug, and refit the cowl.
  9. Refit the arms at the photographed park position and torque the nuts.
  10. Run the wipers through a full cycle and confirm they park correctly and do not hit the A-pillar.

A/C system evacuate and recharge

Safety first

Refrigerant freezes skin and displaces oxygen in a closed space. Wear gloves and goggles. Never vent refrigerant to atmosphere - recover it.

Worth knowing

Class 8 trucks use R-134a or R-1234yf depending on build year. The two are not interchangeable, they use different oils, and the service fittings differ. Confirm which system is on the truck from the under-hood label before connecting a machine.

Labor time
1.5 hr · 1.0-2.0 hr; recover, evacuate, recharge; leak search adds 0.5 hr
Book time — actual time varies by shop and truck condition
Tools
Recovery machine with scales, Manifold gauges, Leak detector, Thermometer
Parts
Refrigerant to the specified charge weight, PAG oil if a component was replaced
  1. Check the system operates at all - a compressor that never engages may be a pressure switch or a fuse, not a charge problem.
  2. Recover the existing refrigerant and record how much came out.
  3. Pressure-test with nitrogen and find the leak before recharging. Charging a leaking system wastes refrigerant and time.
  4. Repair the leak, then replace the receiver-drier or accumulator if the system was open to atmosphere.
  5. Evacuate to a deep vacuum and hold it for at least 30 minutes to confirm it holds.
  6. Charge by weight to the spec on the under-hood label, not by gauge pressure alone.
  7. Check vent temperature at the centre duct with the engine at fast idle and the blower on high.
  8. Verify the compressor cycles normally and the condenser fan or fan clutch engages.

A/C compressor and clutch replacement

Safety first

Recover refrigerant before opening the system. Escaping refrigerant can cause frostbite.

Labor time
3.0 hr · 2.0-4.0 hr; system recover and recharge included
Book time — actual time varies by shop and truck condition
Tools
Recovery machine, Manifold gauges, Torque wrench, Clutch puller, Feeler gauges
Parts
Compressor, clutch assembly if separate, O-rings, receiver-drier, PAG oil
  1. Recover the refrigerant and disconnect the batteries.
  2. Release the belt tension and remove the drive belt.
  3. Disconnect the suction and discharge lines and cap the open ends immediately.
  4. Remove the mounting bolts and lift the compressor out, draining and measuring the oil.
  5. If only the clutch failed, inspect the coil and the air gap rather than replacing the whole compressor.
  6. Fit the new compressor, adding the specified amount of PAG oil for the components replaced.
  7. Torque the mounts, reconnect the lines with new O-rings.
  8. Replace the receiver-drier - it is not reusable once the system is open.
  9. Refit the belt, evacuate, and recharge by weight.
  10. Check clutch air gap and confirm engagement, then verify vent temperature.

Blower motor and resistor replacement

Safety first

Disconnect the batteries. The blower can start unexpectedly if the key is cycled.

Labor time
1.5 hr · 1.0-2.5 hr; resistor replacement adds 0.3 hr
Book time — actual time varies by shop and truck condition
Tools
Trim tools, Socket set, Torque screwdriver, Multimeter
Parts
Blower motor, resistor or control module, foam gasket
  1. Disconnect the batteries.
  2. Locate the blower housing, usually under the passenger side of the dash or behind the hood cowl.
  3. Disconnect the electrical plug and check for melted terminals - a common cause of 'works on high only'.
  4. Remove the retaining screws and lower the motor out.
  5. Clean the housing of leaves and debris, which is often what killed the motor.
  6. If speeds are missing, replace the resistor pack or control module at the same time.
  7. Fit the new motor with a new foam gasket so air does not leak around it.
  8. Reconnect and test every speed setting.

Cabin air filter replacement

Safety first

None beyond normal care. Disconnect the batteries if the filter sits near any wiring.

Labor time
0.4 hr · 0.3-0.5 hr; simple access job
Book time — actual time varies by shop and truck condition
Tools
Trim tools or a screwdriver, Vacuum
Parts
Cabin air filter
  1. Locate the filter housing - usually behind the glovebox or under the cowl panel.
  2. Open the housing and note the airflow arrow on the old filter.
  3. Remove the old filter and vacuum out leaves and debris from the housing.
  4. Fit the new filter with the arrow pointing the same way as the old one.
  5. Close the housing until it clicks.
  6. Run the blower on high and confirm airflow has improved.

Heater core replacement

Safety first

Drain coolant cold. The core sits inside the cab, so a leak soaks the floor and fogs the screen.

Labor time
3.5 hr · 2.5-5.0 hr; dash panels come out — the worst HVAC job
Book time — actual time varies by shop and truck condition
Tools
Coolant container, Trim tools, Torque screwdriver, Hose clamp pliers
Parts
Heater core, O-rings or hose clamps, coolant
  1. Drain the cooling system below the heater core level.
  2. Clamp or plug the heater hoses at the firewall before disconnecting them.
  3. Remove the dash panels or the HVAC housing cover that blocks access.
  4. Disconnect the hoses and the blend door actuator linkage.
  5. Slide the core out, catching any residual coolant in a tray.
  6. Inspect the housing for cracks and the blend door for a broken hinge.
  7. Fit the new core with new O-rings or seals - never reuse them.
  8. Reconnect the hoses and refill with the correct coolant.
  9. Bleed the system with the heater on full hot.
  10. Test for heat at the vents and check the floor for leaks.

Fifth wheel service and adjustment

Safety first

Never put any part of your body between the tractor and trailer. Use a proper stand when working under a coupled unit.

Labor time
1.0 hr · 0.5-1.5 hr; grease and jaw inspection
Book time — actual time varies by shop and truck condition
Tools
Grease gun, Torque wrench to 500 ft-lb, Feeler gauges, Pry bar
Parts
Fifth wheel grease, jaw and wedge kit if worn, mounting hardware
  1. Uncouple the trailer and park the tractor on level ground.
  2. Inspect the top plate for cracks and the jaws for wear or a broken spring.
  3. Check the jaw adjustment with a gauge or a known-good kingpin - a loose jaw drops trailers.
  4. Lubricate the top plate and the jaw mechanism with the specified fifth wheel grease.
  5. Check the mounting brackets and bolts for looseness and cracks.
  6. Torque the mounting bolts to spec.
  7. Test the coupling: back under a trailer, listen for the click, and pull-test with the landing gear just clear.

Exhaust manifold and gasket replacement

Safety first

Exhaust components are hot and the studs snap. Let the engine cool fully and soak the studs before starting.

Labor time
3.0 hr · 2.0-4.0 hr; stud extraction adds 2-4 hr per broken stud
Book time — actual time varies by shop and truck condition
Tools
Torque wrench, Stud extractor, Surface straightedge, Penetrating oil
Parts
Exhaust manifold, gaskets, studs and nuts, heat shield hardware
  1. Let the engine cool completely and disconnect the batteries.
  2. Soak the manifold studs with penetrant and let them sit - snapping a stud turns a two-hour job into a two-day one.
  3. Remove the heat shield and disconnect the turbo or exhaust pipe flange.
  4. Work the nuts loose evenly, a little at a time, from the centre outward.
  5. Remove the manifold and scrape the head surface clean without gouging it.
  6. Check the head surface and the new manifold flange with a straightedge.
  7. Fit new gaskets and new studs, and set the manifold in place.
  8. Torque in the OEM sequence, from the centre outward, in at least two stages.
  9. Refit the heat shield and reconnect the exhaust.
  10. Run the engine and listen for a new exhaust tick when cold.

DPF filter removal and replacement

Safety first

The aftertreatment box stays hot for a long time after shutdown. Let it cool fully - a DPF skin burn is instant.

Worth knowing

A DPF that keeps loading is usually a symptom: a leaking doser, a failed regen, or an engine burning oil. Replacing the filter without fixing the cause just loads the new one.

Labor time
4.0 hr · 3.0-5.0 hr; add 1.0 hr if sensors are seized
Book time — actual time varies by shop and truck condition
Tools
Heat-resistant gloves, Torque wrench, Band clamp wrench, Lifting aid, Diesel exhaust fluid-safe tray
Parts
DPF filter or cleaned exchange unit, gaskets, band clamps, sensor grommets
  1. Read and record the soot load and ash load before touching anything.
  2. Let the exhaust cool completely and disconnect the batteries.
  3. Disconnect the pressure sensor tubes and the temperature sensor connectors, and label them.
  4. Release the band clamps and separate the DPF canister from the DOC and SCR sections.
  5. With a second person, lift the filter out - a loaded Class 8 DPF is heavy and awkward.
  6. Inspect the inlet face for oil or coolant staining, which points at the real problem.
  7. Fit the new or cleaned filter with new gaskets and clamps, seating the sensor bosses.
  8. Torque the band clamps to the clamp maker's spec - over-torque crushes the canister.
  9. Reconnect the sensors in the positions you labelled.
  10. Start the engine and confirm no exhaust leaks, then run a parked regen and watch the pressure differential.

DEF dosing module and filter replacement

Safety first

DEF crystallises and corrodes. Rinse any spill with clean water immediately. Do not let DEF freeze in the lines.

Labor time
1.5 hr · 1.0-2.0 hr; priming and code clear adds 0.5 hr
Book time — actual time varies by shop and truck condition
Tools
Torque wrench, Line wrenches, Diagnostic tool, Clean water for rinsing
Parts
Dosing module, filter kit, O-rings, mounting hardware
  1. Disconnect the batteries and let system pressure bleed down.
  2. Drain the DEF line by commanding the dosing test with the diagnostic tool.
  3. Disconnect the DEF supply and return lines and cap them.
  4. Remove the module mounting bolts and lift it out.
  5. Inspect the old module inlet screen for crystallised DEF, which confirms contamination.
  6. Clean the mounting surface and rinse any crystallised DEF away with clean water.
  7. Fit the new module with a new filter and new O-rings - never reuse a DEF O-ring.
  8. Reconnect the lines and run the dosing test to prime and check for leaks.
  9. Clear the codes and confirm the SCR efficiency monitors pass on a road test.

DEF tank level and quality sensor replacement

Safety first

DEF is mildly corrosive to skin and attacks some metals. Wear gloves.

Labor time
1.0 hr · 0.5-1.5 hr; tank drain adds 0.5 hr
Book time — actual time varies by shop and truck condition
Tools
Torque wrench, Trim tools, Diagnostic tool, Refractometer
Parts
Tank header or sensor assembly, gasket, mounting ring
  1. Test the DEF in the tank with a refractometer first - a genuine 32.5% reading rules out contamination.
  2. Disconnect the batteries and drain the tank into a clean container if the sensor is in the header.
  3. Disconnect the electrical connector and check the pins for corrosion or DEF creep.
  4. Release the locking ring or remove the header bolts.
  5. Lift the header out carefully - the level float arms are easy to bend.
  6. Fit the new sensor with a new gasket and seat the locking ring fully.
  7. Refill with fresh ISO 22241 DEF.
  8. Clear the codes and run the tank level monitor to confirm the gauge responds.

EGR valve replacement

Safety first

Drain coolant cold. EGR components carry both exhaust gas and coolant.

Labor time
1.5 hr · 1.0-2.0 hr; calibration adds 0.5 hr
Book time — actual time varies by shop and truck condition
Tools
Torque wrench, Gasket scraper, Coolant container, Diagnostic tool
Parts
EGR valve, gaskets, coolant if the valve is liquid-cooled
  1. Read the EGR position and command codes before removal, and note whether the valve is stuck open or closed.
  2. Drain coolant below the valve if it is liquid-cooled, and disconnect the batteries.
  3. Disconnect the electrical connector and any coolant lines.
  4. Remove the mounting bolts and lift the valve out.
  5. Clean the mating surfaces flat and check the intake passage for heavy soot build-up.
  6. Fit the new valve with new gaskets and torque the bolts in a crossing pattern.
  7. Reconnect coolant lines and refill, bleeding the system.
  8. Clear the codes and command an EGR sweep with the diagnostic tool to confirm full travel.

Engine oil cooler replacement

Safety first

Oil and coolant mix if the cooler fails internally - that is how you diagnose it. Drain both cold.

Labor time
3.0 hr · 2.0-4.0 hr; both fluids drained and refilled
Book time — actual time varies by shop and truck condition
Tools
Coolant and oil drain containers, Torque wrench, Gasket scraper, Cleaning solvent
Parts
Oil cooler, gaskets and O-rings, coolant, engine oil and filter
  1. Look for oil in the coolant or coolant in the oil first; that confirms an internal cooler failure.
  2. Drain both the cooling system and the engine oil.
  3. Remove the oil filter and any lines blocking access.
  4. Disconnect the coolant hoses and remove the cooler mounting bolts.
  5. Lift the cooler out and clean both mating surfaces.
  6. Fit the new cooler with new gaskets and O-rings, and torque in a crossing pattern.
  7. Reconnect hoses, refill coolant, and fit a new oil filter with fresh oil.
  8. Run to operating temperature, then re-check both fluids for cross-contamination and top up.

Fuel tank and sender replacement

Safety first

A full Class 8 tank holds 150+ gallons and weighs over half a ton. Drain it first. No sparks, no smoking, fire extinguisher within reach.

Labor time
3.0 hr · 2.0-4.0 hr; drain first, add 1.0 hr if straps are seized
Book time — actual time varies by shop and truck condition
Tools
Tank strap wrench, Torque wrench, Line wrenches, Lifting aid or transmission jack, Fire extinguisher
Parts
Fuel tank, sender unit, gasket, straps and isolators if worn, fuel hose
  1. Drain the tank into approved containers - do not try to lower a loaded tank.
  2. Disconnect the batteries.
  3. Disconnect the fuel supply and return lines and cap them.
  4. Disconnect the sender wiring and the tank ground strap.
  5. Support the tank on a jack and remove the strap bolts.
  6. Lower the tank and set it down safely.
  7. Transfer the sender, filler neck and any brackets to the new tank with new gaskets.
  8. Set the new tank on fresh isolators, fit the straps and torque the strap bolts to spec.
  9. Reconnect the lines, sender and ground, then fill and check for leaks before starting.

Fuel lift pump replacement

Safety first

Release fuel pressure before opening any line. Diesel on a hot manifold is a fire.

Labor time
1.5 hr · 1.0-2.0 hr; priming adds 0.5 hr
Book time — actual time varies by shop and truck condition
Tools
Line wrenches, Torque wrench, Drain container, Diagnostic tool
Parts
Lift pump or fuel pump module, gaskets, fuel hose clamps
  1. Release fuel pressure per the OEM procedure and disconnect the batteries.
  2. Clamp or plug the fuel lines before disconnecting to limit spillage.
  3. Disconnect the supply, return and electrical connector.
  4. Remove the mounting bolts and lift the pump out.
  5. Inspect the old pump inlet screen for debris - a blocked screen kills the new pump too.
  6. Fit the new pump with new gaskets and torque the mounts.
  7. Reconnect the lines and connector.
  8. Cycle the key several times to prime, then start and check for leaks at pressure.
  9. Clear codes and confirm the fuel delivery pressure reads within spec at load.

Radiator hose and coolant pipe replacement

Safety first

Drain cold. A hose that lets go on the road costs an engine.

Tools
Hose clamp pliers, Coolant container, Torque wrench, Inspection light
Parts
Hoses and formed pipes, constant-torque clamps, coolant
  1. Drain coolant below the hose level.
  2. Squeeze the old hose - a hose that feels crunchy or spongy inside is finished even if it looks fine.
  3. Release the clamps and twist the hose to break the seal rather than levering on the pipe.
  4. Clean the pipe barbs of old rubber and scale.
  5. Fit new constant-torque clamps if the originals are the spring type and have relaxed.
  6. Slide the new hose on fully and seat it past the barb.
  7. Position the clamp behind the barb and torque to spec.
  8. Refill and bleed with the heater on hot, then run to temperature and pressure-test.

Air reservoir (tank) replacement

Safety first

Drain all air pressure first. A pressurised tank with a stuck drain valve can vent violently.

Labor time
1.5 hr · 1.0-2.5 hr; all air drained, lines labelled
Book time — actual time varies by shop and truck condition
Tools
Line wrenches, Torque wrench, Strap bolts, Soap solution
Parts
Air reservoir, mounting straps and isolators, fittings, drain valve
  1. Drain every tank in the system and confirm zero pressure on the gauge.
  2. Label every line before disconnecting - a mis-plumbed tank defeats the check valves.
  3. Disconnect the supply, delivery and drain lines and cap them.
  4. Remove the mounting strap bolts and lift the tank out.
  5. Inspect the straps and isolators for corrosion; replace if pitted.
  6. Fit the new tank with the drain valve at the lowest point.
  7. Reconnect the lines in the labelled positions and torque the fittings.
  8. Recharge the system and check every fitting with soap solution.
  9. Confirm the low-pressure warning and the build-up time are both correct.

Gladhand and trailer air line replacement

Safety first

Drain the tractor protection system. A gladhand that whips under pressure causes serious injury.

Labor time
0.5 hr · 0.3-0.7 hr; per gladhand
Book time — actual time varies by shop and truck condition
Tools
Line wrenches, Torque wrench, Soap solution, Zip ties
Parts
Gladhand coupler, coupler seal, air line, fittings
  1. Drain the air system and confirm zero pressure at the couplers.
  2. Disconnect the old gladhand and inspect the coupler seal for cracking.
  3. Check the line for chafing where it runs through the frame or the cab guard.
  4. Fit the new gladhand with a new seal and torque to spec.
  5. Route the new line clear of sharp edges and secure it with zip ties at the original points.
  6. Recharge and check both couplers with soap solution.
  7. Couple to a trailer and confirm the tractor protection valve holds pressure when the lines are disconnected.

Brake treadle (foot) valve replacement

Safety first

This is the valve that stops the truck. Drain all air first and confirm zero pressure.

Labor time
1.5 hr · 1.0-2.0 hr; pedal linkage and trim removal included
Book time — actual time varies by shop and truck condition
Tools
Line wrenches, Torque wrench, Trim tools, Soap solution
Parts
Treadle valve, mounting hardware, line seals
  1. Drain the air system completely.
  2. Remove the floor mat and trim to reach the valve.
  3. Label the supply and delivery lines - getting these crossed gives you brakes on the wrong circuit.
  4. Disconnect the lines and the treadle linkage or pedal arm.
  5. Remove the mounting bolts and lift the valve out.
  6. Fit the new valve in the same orientation, with new seals on the lines.
  7. Torque the line fittings and the mounting bolts.
  8. Reconnect the pedal and check the free play matches the old valve.
  9. Recharge, check for leaks, and test that both circuits apply and release smoothly.

Air compressor governor replacement

Safety first

Drain the air system. The governor controls when the compressor loads, so a wrong setting can overpressure the system.

Labor time
0.7 hr · 0.5-1.0 hr; cut-in/cut-out test included
Book time — actual time varies by shop and truck condition
Tools
Line wrenches, Torque wrench, Pressure gauge, Soap solution
Parts
Governor, mounting O-ring or gasket
  1. Drain the air system and remove the governor mounting bolts.
  2. Note the cut-out pressure on the old unit and compare with the spec for the truck.
  3. Disconnect the balance line and the unloader line.
  4. Fit the new governor, replacing the mounting O-ring or gasket.
  5. Reconnect the lines and torque.
  6. Recharge and watch the gauge: cut-out should occur at the specified pressure and cut-in about 20-25 psi below it.
  7. If the compressor will not unload, check the unloader line for a blockage before blaming the governor.

Air disc brake pads and rotor

Safety first

Cage the spring brake and chock the wheels. Never let a caliper hang on its air hose.

Worth knowing

Air disc brakes do not have slack adjusters. If the pads are wearing unevenly, look at the caliper guide pins and the rotor runout, not the adjustment.

Labor time
1.5 hr · 1.0-2.5 hr per axle; guide pin service included
Book time — actual time varies by shop and truck condition
Tools
Caliper piston retraction tool, Torque wrench to 400 ft-lb, Micrometer, Dial indicator
Parts
Brake pads, pad retaining hardware, rotor if worn past spec
  1. Chock the wheels, drain the air, and cage the spring brake on that axle.
  2. Remove the wheel.
  3. Remove the pad retaining bar and spring, then withdraw the pads.
  4. Inspect the rotor for scoring, heat cracks and lipping, and measure thickness against the minimum.
  5. Retract the caliper pistons fully with the proper tool - never lever on the rotor.
  6. Clean the caliper carrier and check the guide pins for corrosion and free movement.
  7. Fit new pads with new retaining hardware, and grease the specified contact points with the supplied grease.
  8. Check rotor runout with a dial indicator if the old pads wore tapered.
  9. Refit the wheel, torque the nuts in a star pattern to 450-500 ft-lb.
  10. Recharge, release the spring brake, and bed the pads in with a series of controlled stops.

Wheel and tyre change (roadside or shop)

Safety first

Never put any part of your body under a vehicle held only by a jack. Chock the diagonally opposite wheel, and on a dual, deflate the tyre before removing a damaged wheel.

Labor time
0.7 hr · 0.5-1.0 hr; per wheel; add 0.3 hr if studs need cleaning
Book time — actual time varies by shop and truck condition
Tools
Torque wrench to 600 ft-lb, Impact wrench, Wheel dolly, Chocks, Jack rated for the axle
Parts
Wheel and tyre assembly, new wheel nuts if damaged
  1. Park on firm level ground, set the parking brake, and chock the diagonally opposite wheel.
  2. Crack the wheel nuts loose before lifting - a wheel spinning in the air cannot be broken loose.
  3. Lift the axle until the tyre clears the ground and support it on a stand.
  4. Remove the nuts and lift the wheel off with a dolly, not your back.
  5. Clean the hub pilot and the nut seats of rust and debris - dirt between the faces loses clamp load.
  6. Lift the new assembly on, aligning the valve stem for access.
  7. Fit the nuts dry and hand-tight in a star pattern.
  8. Torque in a star pattern to 450-500 ft-lb for M22 hub-piloted, in at least two passes.
  9. Lower the truck and re-torque after 50-100 miles of driving.
  10. Check the tyre pressure cold against the load table, not against what was in the old tyre.

Wheel stud replacement

Safety first

Never heat or hammer a stud into a hub. A stud that is not fully seated will fail and take the wheel with it.

Labor time
1.0 hr · 0.5-1.5 hr; per stud; press required
Book time — actual time varies by shop and truck condition
Tools
Stud press or hydraulic stud tool, Torque wrench, Brass drift, Dial indicator
Parts
Replacement studs, new nuts
  1. Remove the wheel and the hub or drum as needed for access.
  2. Inspect every stud in the hub - if one failed, the neighbours have been overloaded.
  3. Press the old stud out from the back with the proper tool, never with a hammer.
  4. Clean the hole and check for elongation or cracking in the hub flange.
  5. Press the new stud in until the head seats fully against the hub face.
  6. Verify seating by checking the stud height against the others.
  7. Refit the wheel and torque the nuts in a star pattern.
  8. Re-check torque after 50-100 miles.

Brake hose and fitting repair

Safety first

Drain the air system and confirm zero pressure. A chafed brake line can leave you with no brakes on one circuit.

Labor time
0.8 hr · 0.5-1.5 hr; per line; tracing adds time
Book time — actual time varies by shop and truck condition
Tools
Line wrenches, Tube cutter and flaring tool if replacing hard line, Soap solution
Parts
Brake hose or line, fittings, clips
  1. Drain the air system completely.
  2. Trace the line from the valve to the chamber and find the actual damage rather than replacing the visible section.
  3. Disconnect both ends and note the routing through every clip.
  4. Fit the new hose or line along the same path, keeping it clear of the frame edge and exhaust.
  5. Support the line every 18-24 inches with clips so vibration cannot fatigue it.
  6. Torque the fittings.
  7. Recharge and check every joint with soap solution.
  8. Apply and release the brakes several times and confirm no leak and a full stroke.

Ride height and leveling valve adjustment

Safety first

Support the frame before working under an air suspension. A deflating bag drops the chassis fast.

Labor time
1.0 hr · 0.5-1.5 hr; ride height re-set after
Book time — actual time varies by shop and truck condition
Tools
Torque wrench, Tape measure, Wrenches, Soap solution
Parts
Leveling valve if failed, linkage rod and clips
  1. Park on level ground and measure the ride height from the frame to the axle at the specified points.
  2. Compare with the OEM ride height spec - do not adjust to what looks level.
  3. If the height is wrong, check the linkage rod first; a bent or disconnected rod is the usual cause.
  4. Loosen the adjusting clamp and move the valve arm to correct the height.
  5. Cycle the suspension by loading and unloading, and re-measure.
  6. If the valve will not hold height, replace it and re-set the linkage.
  7. Check the valve and lines for leaks with soap solution.

Spring hanger and shackle bushing replacement

Safety first

Support the frame and the axle independently so the spring is not under load.

Labor time
1.5 hr · 1.0-2.5 hr; per spring eye; press required
Book time — actual time varies by shop and truck condition
Tools
Press or bushing driver, Torque wrench, Jack and stands, Pry bar
Parts
Bushings, shackle pins, hanger bolts
  1. Support the frame and axle, then pry-test the spring eyes for movement.
  2. Remove the shackle bolts or the hanger pin.
  3. Press the old bushings out, noting the direction they were fitted.
  4. Clean the eye and inspect for cracks or out-of-round.
  5. Press the new bushings in square, flush with the eye face.
  6. Fit new shackle pins or bolts with new hardware.
  7. Torque with the suspension at ride height, not hanging.
  8. Road test and confirm the clunk over bumps is gone.

Cab suspension air bag replacement

Safety first

Drain the cab suspension air first. Support the cab before removing a bag.

Labor time
1.0 hr · 0.5-1.5 hr; cab supported, air drained
Book time — actual time varies by shop and truck condition
Tools
Jack, Torque wrench, Air line wrench, Soap solution
Parts
Cab air bag, mounting hardware, air line fitting
  1. Drain the cab suspension air at the valve or tank.
  2. Support the cab at the rear with a jack so the bag is unloaded.
  3. Disconnect the air line and cap it.
  4. Remove the upper and lower mounting bolts.
  5. Collapse and remove the old bag; check the mounts for cracks.
  6. Fit the new bag with the alignment pins in the correct holes.
  7. Torque the mounts and reconnect the air line.
  8. Recharge and check with soap solution, then confirm the cab sits level.

Seven-way trailer cord replacement

Safety first

Disconnect the batteries. A shorted trailer cord blows the lighting fuse and can melt a harness.

Worth knowing

The pinout is fixed by SAE J560: 1 white ground, 2 black tail, 3 yellow left turn, 4 red stop, 5 green right turn, 6 brown auxiliary, 7 blue centre. Check the wiring diagram sheet before you cut.

Labor time
0.8 hr · 0.5-1.5 hr; circuit test included
Book time — actual time varies by shop and truck condition
Tools
Screwdriver set, Multimeter, Wire cutters, Electrical tape and zip ties
Parts
Seven-way cord with plug, strain relief, terminal ends
  1. Disconnect the batteries.
  2. Open the junction box or the plug end and photograph the terminal layout.
  3. Test each circuit with a multimeter before cutting, so you know which ones worked.
  4. Disconnect the cord and pull it out of the strain relief.
  5. Feed the new cord through the same path and secure the strain relief.
  6. Land each wire on the terminal matching the J560 pinout, and tug-test every one.
  7. Reconnect the batteries and test every function: tail, left, right, stop, and auxiliary.
  8. Check the ground continuity from the plug pin 1 to the frame.

Fuse and relay diagnosis

Safety first

Never replace a blown fuse with a larger one or with foil. A fuse is there to protect the wire, not the load.

Labor time
0.5 hr · 0.3-1.0 hr; diagnosis time not included
Book time — actual time varies by shop and truck condition
Tools
Test light or multimeter, Fuse puller, Relay puller, Wiring schematic for the VIN
Parts
Fuses, relays as needed
  1. Identify the fuse by the VIN-specific schematic, not by guessing from the layout.
  2. Test the fuse with a meter across both blades with the circuit live - a visual check misses hairline failures.
  3. If the fuse is good, swap the relay with an identical one from a non-critical circuit and retest.
  4. Check for power at the relay coil and at the load side of the contact.
  5. If a fuse blows again immediately, stop and find the short with a meter; do not keep feeding it fuses.
  6. Inspect the harness where it passes through the frame or a bulkhead for chafe.
  7. Fit the correct-rated fuse and confirm the circuit works under load.

Battery replacement

Safety first

Remove the ground first and refit it last. Batteries vent hydrogen - no sparks. Rings and metal watch straps off.

Labor time
1.0 hr · 0.5-1.5 hr; for the full set; clean and test included
Book time — actual time varies by shop and truck condition
Tools
Wrenches, Battery lift or two people, Terminal brush, Multimeter
Parts
Batteries (replace the set together), terminal hardware, anti-corrosion spray
  1. Disconnect the ground cables first, then the positive cables.
  2. Note which cable goes to which terminal before removing anything.
  3. Lift the batteries out with a proper lift - a Class 8 battery is 60-70 lb each.
  4. Clean the tray and check it for corrosion and cracks.
  5. Clean the terminals and cable ends to bare metal.
  6. Fit the new batteries in the same orientation, positives and negatives matching the original layout.
  7. Torque the terminal nuts - snug plus a quarter turn is enough for a lead post.
  8. Refit the positives first, then the grounds.
  9. Check charging voltage at the batteries and confirm the ECM has no low-voltage codes.

Ground strap and engine ground repair

Safety first

Disconnect the batteries before removing an engine ground - the starter current will find another path through your tools.

Labor time
0.7 hr · 0.5-1.0 hr; per strap; voltage drop test after
Book time — actual time varies by shop and truck condition
Tools
Wrenches, Multimeter, Wire brush, Dielectric grease
Parts
Ground straps, bolts, star washers
  1. Disconnect the batteries.
  2. Measure voltage drop from the engine block to the frame while cranking - more than 0.2 V means a bad ground.
  3. Inspect every strap for green corrosion, broken strands and loose bolts.
  4. Remove the straps and clean both mounting surfaces to bare metal.
  5. Refit with star washers so the connection bites through paint.
  6. Apply dielectric grease over the finished joint.
  7. Check the cab-to-frame and battery-to-frame grounds at the same time.
  8. Reconnect and re-measure the voltage drop.

Horn replacement

Safety first

Disconnect the batteries. Horns draw high current and the circuit is usually unfused at the horn end.

Labor time
0.7 hr · 0.5-1.0 hr; per horn
Book time — actual time varies by shop and truck condition
Tools
Wrenches, Multimeter, Wire brush
Parts
Horn, mounting bracket, hardware
  1. Disconnect the batteries.
  2. Test for power and ground at the horn connector while an assistant presses the button.
  3. If there is no power, the problem is the button or the relay, not the horn.
  4. Remove the mounting bolt and the connector.
  5. Clean the bracket and mounting surface.
  6. Fit the new horn with the trumpet pointing down and back so water cannot collect.
  7. Torque the mount and reconnect.
  8. Test both the city and highway horn if fitted.

Turn signal and wiper multifunction switch

Safety first

Disconnect the batteries and let the airbag system discharge before removing a steering wheel with an airbag.

Worth knowing

Trucks with a driver airbag need the airbag disabled and the module discharged per the OEM procedure before the wheel comes off. Do not shortcut this.

Labor time
1.5 hr · 1.0-2.5 hr; airbag disable adds 1.0 hr
Book time — actual time varies by shop and truck condition
Tools
Trim tools, Steering wheel puller, Torque wrench, Multimeter
Parts
Multifunction switch assembly
  1. Disconnect the batteries and wait the specified discharge time.
  2. Remove the steering column shrouds.
  3. Disable and remove the airbag if fitted, following the OEM sequence.
  4. Mark the steering wheel to the shaft and remove the retaining nut and wheel.
  5. Unplug the switch connectors and remove the switch mounting screws.
  6. Fit the new switch and reconnect the plugs.
  7. Refit the wheel aligned to the marks and torque the nut to spec.
  8. Refit the airbag and shrouds, reconnect the batteries.
  9. Test every function: indicators, hazards, wipers, washers and horn.

A/C condenser replacement

Safety first

Recover refrigerant first. Never open a charged system to atmosphere.

Labor time
2.0 hr · 1.5-3.0 hr; grille and bumper removal adds time
Book time — actual time varies by shop and truck condition
Tools
Recovery machine, Line wrenches, Torque wrench, Fin comb
Parts
Condenser, O-rings, receiver-drier, refrigerant
  1. Recover the refrigerant and record the weight.
  2. Disconnect the batteries and remove any grille or bumper trim blocking access.
  3. Disconnect the inlet and outlet lines and cap them.
  4. Remove the mounting brackets and lift the condenser out.
  5. Inspect the old condenser for stone damage and oil staining, which shows the leak point.
  6. Fit the new condenser with new O-rings and new isolators.
  7. Replace the receiver-drier whenever the system has been open.
  8. Torque the line fittings, evacuate, and recharge by weight.
  9. Confirm vent temperature and that the condenser fan engages.

Blend door actuator replacement

Safety first

Disconnect the batteries before working behind the dash.

Labor time
1.5 hr · 1.0-2.5 hr; calibration adds 0.5 hr if supported
Book time — actual time varies by shop and truck condition
Tools
Trim tools, Torque screwdriver, Diagnostic tool
Parts
Blend door actuator, mounting screws
  1. Identify which actuator controls the fault - heat only, defrost only, or one side - before removing anything.
  2. Disconnect the batteries.
  3. Remove the lower dash panels for access.
  4. Unplug the actuator and remove the mounting screws.
  5. Check the door itself moves freely by hand; a seized door burns out a new actuator.
  6. Fit the new actuator with the spline aligned to the door shaft.
  7. Reconnect and run a calibration or self-test with the diagnostic tool if the system supports it.
  8. Test full hot and full cold at every outlet.

HVAC control panel replacement

Safety first

Disconnect the batteries before removing dash panels - there are live feeds behind them.

Labor time
1.0 hr · 0.5-1.5 hr; trim removal included
Book time — actual time varies by shop and truck condition
Tools
Trim tools, Torque screwdriver, Multimeter
Parts
Control head or panel, bulbs or LEDs if separate
  1. Disconnect the batteries.
  2. Remove the trim around the control head.
  3. Remove the mounting screws and pull the panel forward.
  4. Release the connector locks and unplug - do not pull on the harness.
  5. Fit the new panel and connect the plugs until they click.
  6. Refit the screws and trim.
  7. Reconnect the batteries and test every mode, speed and temperature setting.

Door latch and hinge adjustment

Safety first

Support the door before loosening hinge bolts - a door that drops can crush fingers.

Labor time
1.0 hr · 0.5-1.5 hr; hinge pins may add 0.5 hr
Book time — actual time varies by shop and truck condition
Tools
Torx and hex drivers, Torque wrench, Trim tools, Lubricant
Parts
Latch assembly, striker, hinge pins if worn
  1. Inspect the hinges first: lift the door at the rear edge and feel for play.
  2. Check the striker for wear and the latch for a loose mounting.
  3. Lubricate the latch mechanism and the hinges with the specified grease.
  4. If the door sags, replace the hinge pins or the hinge as an assembly.
  5. Adjust the striker in small increments until the door closes with a firm click and no rattle.
  6. Check the door sits flush with the cab and the seals are not pinched.
  7. Test the interior and exterior handles and the lock.

Hood latch, hinge and tilt assist

Safety first

A Class 8 hood is heavy and can fall. Have a second person or a prop before releasing the assist.

Labor time
0.7 hr · 0.5-1.0 hr; safety catch and assist strut check
Book time — actual time varies by shop and truck condition
Tools
Socket set, Torque wrench, Lifting aid, Lubricant
Parts
Latch assembly, striker, hinge pins or assist strut if worn
  1. Support the hood before releasing any latch or assist.
  2. Inspect the latch for wear and the safety catch for free movement.
  3. Check the hinge pivots for play and the assist strut or spring for loss of force.
  4. Lubricate the latch and hinges.
  5. If the hood will not stay up, replace the gas strut or the torsion spring.
  6. Adjust the latch striker so the hood closes flush and the safety catch engages.
  7. Lower the hood slowly and confirm both latches catch.

Crankcase breather filter service

Safety first

A blocked breather pressurises the crankcase and pushes oil out of every seal. Service it before chasing oil leaks.

Labor time
0.5 hr · 0.3-0.7 hr; simple access job
Book time — actual time varies by shop and truck condition
Tools
Wrenches, Cleaning solvent, Torque wrench
Parts
Breather filter element or coalescing element, gaskets
  1. Locate the breather assembly, usually on the valve cover or the side of the block.
  2. Remove the cover or housing and withdraw the element.
  3. Inspect for sludge and emulsion, which points at a cold-running engine or a coolant leak.
  4. Clean the housing and the drain-back passage.
  5. Fit the new element with a new gasket.
  6. Torque the cover to spec.
  7. Check the drain-back tube is clear and not kinked.

Pinnacle hood and grille removal

Safety first

Support the hood before releasing the hinges.

Labor time
2.0 hr · 1.5-3.0 hr
Book time — actual time varies by shop and truck condition
Tools
Socket set, Torque wrench, Lifting aid, Trim tools
Parts
Hinge hardware, striker
  1. Prop the hood open.
  2. Disconnect lighting and any front connectors.
  3. Mark the hinge positions.
  4. Support and remove the hinge bolts.
  5. Lift clear with two people.
  6. Refit aligned and torque.
  7. Check gaps and latches.

Mack mDRIVE transmission service

Safety first

Automated manual - obey towing restrictions.

Labor time
1.5 hr · 1.0-2.0 hr
Book time — actual time varies by shop and truck condition
Tools
Drain pan, Filler pump, Torque wrench, Mack diagnostic tool
Parts
Mack-approved mDRIVE fluid, filter, gaskets
  1. Warm and park level.
  2. Remove the fill plug first.
  3. Drain and measure.
  4. Replace the filter and clean the magnet.
  5. Refill to the level plug.
  6. Cycle gears with the diagnostic tool.
  7. Road test shift quality.
Print these steps → Torque numbers →
TorqueLibrary — A research compilation, not an OEM manual. Green means published and traceable; amber means second-hand, so check it. Where nothing was published the page says so rather than guessing.
Built from OEM operator manuals, federal service bulletins and industry standards (SAE, TMC, Bendix, Michelin, ConMet, Accuride). Confirm every number against the manual for your specific VIN before you turn a wrench.