Pretrip and Post-Trip Inspections and Maintenance

Pretrip and Post Trip Inspection Checklists

Regulations in both Canada and the United States clearly indicate that it is the driver's responsibility to perform an inspection and ensure the complete road-worthiness of a vehicle before placing it into service for the day. Commercial vehicles may be subject to inspection by authorized inspectors, and an unsafe vehicle can be put "out of service" until the driver or owner repairs it.

IMPORTANT: The pre- and post-trip checklists, and inspections and maintenance procedures detailed in this chapter, are not all-inclusive . Also refer to other component and body manufacturers' instructions for specific inspection and maintenance instructions.

Use the inspection checklists to ensure that vehicle components are in good working condition before each trip. A driver that is familiar with the vehicle, and drives it regularly, can perform the daily inspections, then add the weekly and monthly post-trip inspections as scheduled. If the driver does not operate the vehicle on a consistant basis, all three of the inspection procedures should be performed before the trip.

NOTE: Procedure reference numbers in the checklists reference the corresponding detailed instructions found under the pretrip and post-trip maintenance procedures.

Pre- and post-trip inspections cannot be done quickly. However, careful inspections save time by eliminating stops later to adjust items overlooked or forgotten.

If any system or component does not pass this inspection, it must be corrected before operating the vehicle. Whenever equipment requires adjustment, replacement, repair, addition of lubricants, or a change of lubricants, see the Heavy-Duty Trucks Service Manual for procedures and specifications, and see the Heavy-Duty Trucks Maintenance Manual for lubricant recommendations, specifications, and maintenance intervals.

See Table 11.1 for a list of procedures that should be perfomed daily, before the first trip.

See Table 11.2 for a list of procedures that should be performed weekly, post-trip.

See Table 11.3 for a list of procedures that should be performed monthly, post-trip.

IMPORTANT: Before performing any checks, apply the parking brake and chock the tires.

Procedure Performed (check off)		Daily Pretrip Inspections/Checks	Procedure Reference
	_______	Drain manually drained air reservoirs (that are not equipped with automatic drain valves)	D1
Check	_______	windshield washer reservoir fluid	D2
Check	_______	surge tank coolant level	D3
Inspect	_______	radiator and charge air cooler	D4
Check	_______	engine for fuel, oil, or coolant leaks	—
Inspect	_______	engine and chassis wiring	D5
Inspect	_______	air intake system	D6
Check	_______	intake-air restriction indicator mounted on air intake	D6
Check	_______	engine oil level	D7
Check	_______	power steering fluid level	—
Inspect	_______	fuel tank(s), fuel lines, and connections	D8
Check	_______	fuel level	D9
Check	_______	fuel/water separator	D10
Inspect	_______	front and rear suspension components	D11
Inspect	_______	headlights, mirrors, and window glass, and windshield wipers	D12
Check	_______	doors (open without difficulty and close securely)	—
	_______	Adjust driver's seat, then align rearview and downview mirrors	—
Check	_______	dash-mounted intake-air restriction indicator	D6
Check	_______	oil- and air-pressure warning systems	D13
Check	_______	horn, windshield wipers, and windshield washer	D14
Check	_______	heater, defroster, and optional mirror heat controls	D15
Check	_______	backup alarm	—
Check	_______	panel lights and interior lights	D16
Check	_______	exterior lights and reflectors	D17
Check	_______	tire pressure	D18
Inspect	_______	tire condition	D19
Inspect	_______	rims and wheels	D20
Inspect	_______	hub oil seals and lubrication levels	D21
Check	_______	automatic transmission fluid level	—
Inspect	_______	air brake chambers and pushrods	D22
Inspect	_______	air brake lines	D23
Inspect	_______	slack adjusters	D24
Check	_______	air brake system operation	D25
Inspect	_______	frame rails (missing bolts), crossmembers (bent or loose)	—
Check	_______	mud flaps (aren't damaged, at least 10 inches above the ground, and brackets are secure)	—
Check	_______	exhaust system (mounted securely, connected tightly, no signs of leaks such as soot trails)	—
Inspect	_______	seat belts and tether belts	D26
	_______	Remove chocks and test service brakes	D27
Inspector___________________________________________________ Date ________________

Table 11.1, Daily Pretrip Inspection and Maintenance Checklist

Procedure Performed (check off)		Weekly Post-Trip Inspections/Checks	Procedure Reference
	_______	Manually drain air reservoirs that are equipped with automatic drain valves	—
Inspect	_______	batteries and battery cables	W1
Check	_______	wheel bearing lubricant level	W2
Inspect	_______	steering components	W3
Check	_______	serpentine drive belt condition	W4
Check	_______	V-belt tension	W5
Inspector___________________________________________________ Date ________________

Table 11.2, Weekly Post-Trip Inspection and Maintenance Checklist

Procedure Performed (check off)		Monthly Post-Trip Inspections/Checks	Procedure Reference
	_______	Clean the battery terminals	M1
Inspect	_______	radiator hoses and heater hoses	M2
Check	_______	fluid level in the hydraulic clutch reservoir (if applicable, and if necessary, fill with DOT 4 brake fluid)	—
Check	_______	steering wheel play	M3
Check	_______	outer surfaces of the hood and body (for visible surface breaks and damage)	—
Check	_______	hood tilt damper (attached at both ends)	—
Inspect	_______	brake lining wear	M4
Inspect	_______	driveshaft	—
Inspector___________________________________________________ Date ________________

Table 11.3, Monthly Post-Trip Inspection and Maintenance Checklist

Pretrip and Post Trip Maintenance Procedures

Whenever equipment requires adjustment, replacement, repair, addition of lubricants, or a change of lubricants, see the Heavy-Duty Trucks Service Manual for procedures and specifications, and see the Heavy-Duty Trucks Maintenance Manual for lubricant recommendations, specifications, and maintenance intervals. Specific references to the manual will be found where appropriate.

Daily Pretrip Maintenance Procedures

Drain manually drained air reservoirs.

Water and oil normally enter the air reservoir in the form of vapor because of the heat generated during compression. After the water and oil condense, drain the resulting emulsion as follows:

1.1

Open the wet tank valve. The drain cock or pull chain drain is located on the forward end of the supply air reservoir, which is connected directly to the air compressor. Block the valve open.

When draining the air reservoir, do not look into the air jets or direct them toward anyone. Dirt or sludge particles may be in the airstream and could cause injury.

1.2

Exhaust the remaining air and moisture from the system by opening the drain cocks on the bottoms of the remaining air reservoirs. Block the valves open.

1.3

Water and oil emulsion often form pockets that will not drain while compressed air is in the reservoirs. Because of these pockets, leave the valves blocked open during the first part of the pretrip inspection.

1.4

If the drained water is cloudy or oily, it may indicate a problem with the compressor. If oil is allowed to contaminate the air dryer, it will not remove the water from the air brake system, which could adversely affect braking.

Check the fluid level in the windshield washer reservoir.

Add washer fluid as needed. Unscrew the cap to add fluid.

Washer fluids may be flammable and poisonous. Do not expose washer fluid to an open flame or any burning material, such as a cigarette. Always comply with the washer fluid manufacturer's recommended safety precautions.

Check the coolant level in the surge tank.

See Fig. 11.1 . If the coolant is low, add a 50/50 mixture of water and the type of antifreeze currently installed in your vehicle. Fill the surge tank with coolant to the MAX line when the tank is cool. If the surge tank was empty, start the engine after refilling and check the level again when the engine is at operating temperature.

1. Filler Neck

Fig. 11.1, Coolant Level Checking

Coolant must be filled to the full line of the surge tank. Low coolant could result in engine overheating, which could cause engine damage.

Inspect the radiator and charge air cooler.

4.1

Inspect the radiator and charge air cooler for clogged fins. Use compressed air or water directed from the fan side of the core to backflush any material restricting airflow.

4.2

Inspect the radiator and charge air cooler for damage and accumulated debris. Straighten bent or damaged fins to permit airflow across all areas of the cores.

NOTE: When traveling through areas of high insect concentration, it may be necessary to clean the exterior of the radiator or the charge air cooler core as often as every 200 miles (320 km).

4.3

On vehicles equipped with air conditioning, also inspect and clean the condenser. If clogged, the condenser can restrict airflow through the radiator.

4.4

Check the radiator for leaks. If leaks are found, have the radiator repaired or replaced. See Group 20 of the Heavy-Duty Trucks Service Manual for instructions, or take the vehicle to an authorized Freightliner dealer.

Inspect the engine and chassis wiring.

Check for loose wiring, chafed insulation, and damaged or loose hold-down clamps. Tighten loose wires or hold-down clamps; replace damaged wiring or clamps.

Inspect the air intake system for leaks or damage.

Failure to maintain a sealed air intake system could allow the entry of dirt and contaminants into the engine. This could adversely affect engine performance and result in engine damage.

6.1

Check the intake-air restriction indicator.

6.2

Replace the primary filter element in the air cleaner if the yellow signal stays locked at 25 inH₂O for Caterpillar and Cummins engines or 20 inH₂O for Detroit Diesel engines. See Group 09 of the Heavy-Duty Trucks Service Manual for filter element replacement instructions, or take the vehicle to an authorized Freightliner dealer.

NOTE: After replacing the filter element, reset the restriction indicator by pressing the rubber reset button.

6.3

Inspect the secondary or safety filter element in the air cleaner when replacing the primary element, and replace it when clogged or dirty. This element should be replaced with every third primary element replacement.

6.4

Check the engine air intake piping from the air cleaner to the engine intake. Inspect the piping for loose connections, cracks, torn or collapsed hoses, punctures, and other damage. Tighten loose connections, and have damaged components replaced. Make sure the piping system is airtight so that all intake air passes through the air cleaner.

Check the engine oil level.

If the oil level is at or below the minimum fill (or "add") mark on the dipstick, add enough oil to maintain the level between the minimum fill (or "add") and the maximum fill (or "full") marks on the dipstick. See Fig. 11.2 . Engine lube oil must have a sulfated ash level less than 1.0 wt %; currently referred to as CJ-4 oil. Use the proper SAE viscosity rating for the temperature and time of year.

1. Oil Check
2. Oil Fill

Fig. 11.2, Oil Level Checking

Operating the engine with the oil level below the minimum fill (or "add") mark or above the maximum fill (or "full") mark could result in engine damage.

Inspect the fuel tanks, fuel lines, and connections for leaks.

8.1

Check that the fuel tanks are secured to their mounting brackets and that the mounting brackets are secured to the frame.

8.2

Replace leaking fuel tanks.

8.3

If lines or connections are leaking, have them repaired or replaced.

8.3

For repair and/or replacement procedures, see Group 47 of the Heavy-Duty Trucks Service Manual , or take the vehicle in to an authorized Freightliner dealer.

8.4

If equipped with fuel tank shutoff valves, be sure the valves are fully open.

Never operate the engine with the fuel tank shutoff valves partially closed. This could damage the fuel pump, causing sudden loss of engine power, possibly resulting in serious personal injury due to reduced vehicle control.

Check the fuel level in the fuel tank(s).

To keep condensation to a minimum, fuel tanks should be filled at the end of each day. Federal regulations prohibit filling a fuel tank to more than 95 percent of its liquid capacity.

Never fill fuel tanks to more than 95 percent of their liquid capacity. This could make them more likely to rupture from impact, possibly causing fire and resulting in serious personal injury or death by burning.

Do not mix gasoline or alcohol with diesel fuel. This mixture could cause an explosion, possibly resulting in serious personal injury or death. Do not fill the fuel tanks in the presence of sparks, open flames, or intense heat. These could ignite the fuel, possibly causing severe burns.

IMPORTANT: Engines manufactured since 2007 must use ultralow-sulfur diesel (ULSD) with 15 ppm sulfur content or less, based on ASTM D2622 test procedure. Failure to use ultralow sulfur diesel fuels may void the warranty on emission components.

9.1

Fuel should always be strained or filtered before being put into the tanks. This will lengthen the life of the engine fuel filter and reduce the chances of dirt getting into the engine.

9.2

Before installing the fuel cap, clean the area with a rag, or if necessary, clean the cap with solvent.

9.3

If needed, prime the fuel system. For priming procedures, see the applicable engine manufacturer's manual.

10.

Drain the water from the fuel/water separator as follows:

10.

For a Racor Model 1000FG (see Fig. 11.3 ): Check the water level in the sight bowl. To drain the water, loosen the valve at the bottom of the bowl two full turns and allow the water to run out. Close and tighten the valve finger-tight.

10.

For a Davco Model 321 (see Fig. 11.4 ): If the separator is equipped with a fuel filter and the filter has a vent at the top, open the vent. To drain the water, open the drain valve at the bottom of the separator. Newer separators use a ball valve with a handle that turns 90 degrees. Older separators have a knurled, brass valve that unscrews to open. Allow the water to drain and close the valve finger-tight.

10.

For a Webb Model 525 (see Fig. 11.5 ): Turn the drain valve handle. If nothing flows from the valve, it may be blocked. Use a pencil or screwdriver to clear the valve. Allow the water to drain and then close the valve. Start the engine and raise the rpm for two or three minutes to purge any air from the fuel system.

10.

For ConMet Models (see Fig. 11.6 ): Check the water level in the sight bowl (if equipped). To drain the water, loosen the valve at the bottom and allow the water to run out. Close and tighten the valve finger-tight.

1. Sight Bowl
2. Collected Water
3. Drain Valve

Fig. 11.3, Racor Fuel/Water Separator

Fig. 11.4, Davco Fuel/Water Separator

Fig. 11.5, Webb Fuel/Water Separator

1. Drain Valve

Fig. 11.6, ConMet Fuel/Water Separator

IMPORTANT: When draining fluid from a fuel/water separator, drain the fluid into an appropriate container and dispose of it properly. Many states now issue fines for draining fuel/water separators onto the ground. On all types of separators, stop draining fluid when you see fuel come out of the separator drain valve.

11.

Inspect the front and rear suspension components, including springs, spring hangers, shocks, and suspension brackets.

11.1

Check for broken spring leaves, loose U-bolts, cracks in the suspension brackets, and loose fasteners in the spring hangers and shackles.

11.2

Inspect the shock absorbers for loose fasteners and leaks.

11.3

Tighten all loose fasteners and have any component(s) replaced that are worn, cracked, or otherwise damaged.

11.4

On vehicles with air suspensions, check for leaks. Check air suspension components for cuts and bulges.

12.

Clean the windshield, and the side and rear windows, then check the condition of the windshield wiper arms and blades.

12.

12.1

Replace the wiper arms if the wiper blades are not tensioned against the windshield.

12.1

12.2

Replace damaged or deteriorated wiper blades.

When cleaning windshields and windows, always stand on the ground or on a secure ladder or platform. Use a long-handled window cleaner. Do not use the cab steps, tires, fenders, fuel tanks, engine, or under-hood components to access the windshield or windows. Doing so could cause a fall and result in an injury.

13.

Check the oil- and air-pressure warning systems.

13.1

Check if the warning systems come on when the ignition is turned on, and if not, have the systems repaired.

13.2

Start the engine, then check that the oil- and air-pressure warning systems are operating. The buzzer should stop sounding when the preset minimum is reached. If the air pressure in both systems is above the preset minimum when the engine is started, test the low air pressure warning system by lowering the pressure to below this range, or until the warning system comes on.

13.2

The air pressure in both the primary and secondary air reservoir systems must be above 65 psi (448 kPa) on most vehicles. For vehicles with an optional Bendix dryer reservoir module (DRM), the cut-out pressure is 130 psi (896 kPa).

14.

Make sure that the horn, windshield wipers, and windshield washers are operating properly. These devices must be in good working order for safe vehicle operation.

14.1

Make sure that the horn works. If a horn is not working, have it repaired before trip departure.

14.2

Check the wiper and washer control on the multifunction turn signal switch. If the wipers and/or washers are not working, have them repaired before trip departure.

15.

During cold weather, make sure the heater, defroster, and optional mirror heat controls are operating properly. If so equipped, turn on the mirror heat switch and make sure the system is working.

16.

Check the operation of all the panel lights and interior lights.

16.

Turn on the headlights, dash lights, and four-way flashers and leave them on. If any of the gauge bulbs, the dome light bulbs, or the right- and left-turn indicator bulbs are not working, replace them.

17.

Make sure all the exterior lights are working properly.

17.

Check that all the lights and reflectors are clean. See Fig. 11.7 .

1. Clearance Lights
2. Identification Lights
3. Fog Lights
4. Headlights
5. Turn Signals and Side-Marker Lights
6. Intermediate Turn Signal Lights

Fig. 11.7, Exterior Lights

17.1

Check that the brake lights, taillights, headlights, parking lights, turn signals, marker lights, identification lights, road lights (if so equipped), and front clearance lights are working properly and are clean.

17.2

Test the high and low beams of the headlights.

17.3

Replace light bulbs or sealed beam units that are not working.

17.4

Be sure all reflectors and lenses are in good condition and are clean. Replace any broken reflectors or lenses.

18.

Check tire inflation pressures using an accurate tire pressure gauge.

18.

Tires should be checked when cool. For inflation pressures and maximum loads (per tire) see the tire manufacturer's guidelines.

18.

A weekly pressure loss of 4 psi (28 kPa) or more in a tire may indicate damage. The tire should be inspected and, if necessary, repaired or replaced.

18.1

Be sure valve stem caps are on every tire and that they are screwed on finger-tight.

18.2

Inflate the tires to the applicable pressures if needed.

18.3

If a tire has been run flat or underinflated, check the wheel for proper lockring and side-ring seating, and possible wheel, rim, or tire damage before adding air.

18.3

Moisture inside a tire can result in body ply separation or a sidewall rupture. During tire inflation, compressed air reservoirs and lines must be kept dry. Use well-maintained inline moisture traps and service them regularly.

Do not operate the vehicle with underinflated or overinflated tires. Incorrect inflation can stress the tires and make the tires and rims more susceptible to damage, possibly leading to rim or tire failure and loss of vehicle control, resulting in serious personal injury or death.

IMPORTANT: The load and cold inflation pressure must not exceed the rim or wheel manufacturer's recommendations, even though the tire may be approved for a higher load inflation. Some rims and wheels are stamped with a maximum load and maximum cold inflation rating. If they are not stamped, consult the rim or wheel manufacturer for the correct tire inflation pressure for the vehicle load. If the load exceeds the maximum rim or wheel capacity, the load must be adjusted or reduced.

19.

Inspect each tire for wear, bulges, cracks, cuts, penetrations, and oil contamination.

19.1

Check the tire tread depth. If tread is less than4/32inch (3 mm) on any front tire, or less than2/32inch (1.5 mm) on any rear tire, replace the tire.

19.2

Inspect each tire for bulges, cracks, cuts, and penetrations.

19.3

Inspect each tire for oil contamination. Fuel oil, gasoline, and other petroleum derivatives, if allowed to contact the tires, will soften the rubber and destroy the tire.

20.

Check the wheel nuts or rim nuts for indications of looseness. Examine each rim and wheel component.

20.1

Remove all dirt and foreign material from the assembly. Dirt or rust streaks from the stud holes, metal buildup around stud holes, or out-of-round or worn stud holes may be caused by loose wheel nuts. See Fig. 11.8 and Fig. 11.9 .

Fig. 11.8, Dirt and Rust Streaks from the Stud Holes

20.2

Examine the rim and wheel assembly components (including rims, rings, flanges, studs, and nuts) for cracks, or other damage.

20.2

See Group 33 or Group 35 of the Heavy-Duty Trucks Service Manual for service procedures on the studs and hubs, and see Group 40 in the same manual for wheel and tire servicing, or take the vehicle to an authorized Freightliner dealer.

Have any worn or damaged wheel components replaced by a qualified person using the wheel manufacturer's instructions and the wheel industry's standard safety precautions and equipment. Otherwise a vehicle or workshop accident could occur, possibly resulting in serious personal injury or death.

20.3

Have broken, cracked, badly worn, bent, rusty, or sprung rings and rims replaced. Be sure that the rim base, lockring, and side ring are matched according to size and type.

Fig. 11.9, Worn Stud Holes

20.4

Make sure all wheel nuts are tightened 450 to 500 lbf·ft (610 to 678 N·m) for Accuride wheels with unlubricated threads.

20.4

Use the tightening pattern in Fig. 11.10 for 10-hole wheels, and the tightening pattern in Fig. 11.11 for 8-hole wheels. See Group 40 of the Heavy-Duty Trucks Service Manual for more information.

Fig. 11.10, Tightening Pattern, 10-Hole Wheels

Fig. 11.11, Tightening Pattern, 8-Hole Wheels

Insufficient wheel nut torque can cause wheel shimmy, resulting in wheel damage, stud breakage, and extreme tire tread wear. Excessive wheel nut torque can break studs, damage threads, and crack discs in the stud hole area. Use the recommended torque values and follow the proper tightening sequence.

21.

Inspect the outboard side of all wheel hubs and the hub oil seal area on the inboard side of each wheel for signs of oil leakage. If any oil is found on wheel and tire or brake components, remove the vehicle from service until the leak has been repaired.

21.

If needed, fill the hubs to the level indicated on the hub cap. See Group 35 of the Heavy-Duty Trucks Maintenance Manual for recommended lubricants.

Do not loosen or remove the parking brake clamp ring for any purpose. The parking/emergency brake section of the brake chamber is not intended to be serviced. Serious injury or death may result from sudden release of the power spring.

Before doing any repairs or adjustments on a service/parking brake chamber, read the applicable warnings and instructions in Group 42 of the Heavy-Duty Trucks Service Manual .

22.

Inspect the air brake chamber and the air brake chamber pushrods. See Fig. 11.12 .

A. Do not remove this clamp ring.

1. MGM TR–T (TR Series) Brake Chamber shown

Fig. 11.12, Parking Brake Chamber Clamp

Do not operate the vehicle with the front brakes backed off or disconnected. Backing off or disconnecting the front brakes will not improve vehicle handling and may lead to loss of vehicle control, resulting in property damage or personal injury.

22.1

Check that the air brake chamber is mounted securely on its mounting bracket, and that there are no loose or missing bolts.

22.2

Look for worn clevis pins on brake chamber pushrods and missing or damaged cotter pins on brake chamber pushrod clevis pins. Replace worn clevis pins and install new cotter pins if necessary.

22.3

See if the chamber piston rod is in line with the slack adjuster. Misalignment can cause the piston rod to rub on the non-pressure chamber and cause a dragging brake. See Group 42 of the Heavy-Duty Trucks Service Manual .

If the external breather tube or breather cap is missing or incorrectly installed, road dirt and debris can adversely affect the operation of the brake chamber. Once inside of the chamber, dirt and debris can cause the internal parts of the chamber to deteriorate faster.

22.4

Inspect the exterior surfaces of the chamber for damage. Make sure that breather holes in the non-pressure section(s) are open and free of debris. See Group 42 of the Heavy-Duty Trucks Service Manual to replace any damaged parts.

22.5

On all parking brake installations, make sure the end cover cap or dust plug is securely snapped into place.

NOTE: On most MGM parking brake chambers equipped with an integral release bolt, an end cover cap is installed over the release bolt.

22.6

Check for rusted connections, missing snap rings, and damaged camshaft grease seals. Have damaged or missing parts repaired or replaced.

23.

Inspect the air brake lines.

23.1

Check the clearance between the hoses and the exhaust manifold or other hot spots. Excessive heat will cause material in the hoses to deteriorate rapidly or become brittle. Provide at least 6 inches (150 mm) of clearance. More clearance is recommended if the hose is located above the heat source.

23.2

Check for kinks, dents, or swelling of the hoses. If damaged, have the hose replaced with the same size and type.

NOTE: Do not route the hose on top of anything likely to be stepped on.

23.3

Check for damage to hoses located near moving parts, such as drivelines, kingpins, suspensions, and axles. If moving parts are catching or pinching the lines, correct as needed.

23.4

Check for hose damage caused by abrasion. If abraded, have the hose replaced. Check for the cause of abrasion, such as loose or damaged hose clamps. Have the clamps repaired or replaced as needed.

23.5

Observe the hose cover condition, especially hoses exposed to water splash and ice. If dried out or ragged (the wire or liner is showing through the cover), have the hose(s) replaced.

23.6

Inspect the air tubing, especially tubing made of nylon. In cold weather, nylon tubing is sensitive to damage, such as nicks or cuts. Have nicked or cut tubing replaced, even if it is not leaking.

23.7

Check for kinked or twisted hoses. A seven-percent twist in the hose can reduce its life by up to 90 percent. A twisted hose under pressure tends to untwist, which may loosen the fitting. Reconnect hoses that are twisted.

NOTE: The front brake lines flex continuously in vehicle operation, so they require special examination. Give particular attention to the areas near where they connect to the front air brake chambers. This inspection requires two people, one in the driver seat and another to inspect the brake line connections at the wheels.

23.8

Both wheel air lines must be inspected with the emergency brake set, engine idling, air pressure at 80 to 90 psi (550 to 620 kPa), and the brake pedal held down.

23.9

Turn the wheels to full lock in one direction and inspect both air lines where they connect to the air chambers, then turn the wheels to full lock in the other direction and inspect both lines. If a hose is leaking, have it replaced.

IMPORTANT: ABS-equipped vehicles operating in regions where especially corrosive ice removal chemicals are used may experience higher than normal rotor corrosion. Tone rings should be routinely inspected for corrosion. Severe corrosion of the integral ABS tone ring may cause the ABS warning lamp in the dash to illuminate due to false wheel speed readings. If the ABS warning lamp illuminates at any time other than at vehicle start-up, have the problem repaired immediately.

24.

Inspect the slack adjusters.

24.1

Meritor Slack Adjusters: Check the boot for cuts, tears, or other damage. Have it replaced if necessary.

24.2

Gunite Slack Adjusters: Inspect the slack adjuster for any signs of damage. If damaged, have the slack adjuster replaced.

24.2

Inspect the slack adjuster boot for cuts or tears. If the boot is damaged, have it replaced. See Fig. 11.13 .

1. 7/16-inch Adjusting Nut
2. Grease Fitting
3. Boot
4. Link
5. Brake Chamber Piston Rod
6. Clevis
7. 1/2-inch Clevis Pin
8. 1/4-inch Clevis Pin
9. Grease Relief Opening
10. Slack Adjuster Spline

Fig. 11.13, Gunite Automatic Slack Adjuster

24.3

Haldex Slack Adjusters: Inspect each slack adjuster and anchor strap for damage. See Fig. 11.14 . Have any damaged components replaced.

24.3

Check that the control-arm nut is fully released. If the control arm is in the wrong position, the brakes will drag.

A. Rotate the control arm toward the brake chamber until you can feel it contacting the internal stop.

1. Clevis
2. Slack Adjuster
3. Clevis Pin
4. Manual Adjusting Nut
5. Control Arm
6. Control-Arm Washers and Nut
7. Anchor Strap Slot
8. Anchor Strap
9. Brake Chamber

Fig. 11.14, Haldex Automatic Slack Adjuster

25.

Check the air brake system for proper operation.

25.1

Check the air governor cut-in and cut-out pressures as follows.

25.1

Run the engine at fast idle. The air governor should cut out the air compressor at approximately 120 psi (827 kPa). With the engine idling, apply the brake pedal several times. The air governor should cut in the air compressor at approximately 100 psi (689 kPa). If the air governor does not cut in and out as described above, it must be adjusted to these specifications. If the air governor cannot be adjusted or repaired, replace it before operating the vehicle.

25.2

Check the air pressure buildup time as follows.

25.2

With the air system fully charged to 120 psi (827 kPa), make one full brake application and note the air pressure reading on the gauge. Continue to reduce the air pressure by moderate brake applications to a maximum of 90 psi (620 kPa), then run the engine at governed rpm. If the time required to raise the air pressure to 120 psi (827 kPa) (from the pressure noted after one brake application) is more than 30 seconds, eliminate any leaks or replace the air compressor before operating the vehicle.

25.3

Check the air pressure reserve as follows.

25.3

With the air system fully charged to 120 psi (827 kPa), stop the engine and note the air pressure. Then make one full brake application and observe the pressure drop. If it drops more than 25 psi (172 kPa), all areas of leakage must be eliminated before operating the vehicle.

25.4

Check the air leakage in the system as follows.

25.4

With the parking brake (spring brake) applied, the transmission out of gear, and the tires chocked, charge the air system until cut-out pressure of 120 psi (827 kPa) is reached.

25.4

With the service brakes released, shut down the engine, wait one minute and note the air pressure gauge reading. Observe the air pressure drop in psi (kPa) per minute.

25.4

Charge the air system until cut-out pressure of 120 psi (827 kPa) is reached. With the parking brakes released and the service brake applied, shut down the engine, wait one minute and note the air pressure gauge reading. Observe the air pressure drop in psi (kPa) per minute.

25.4

If leakage exceeds the limits shown in Table 11.4 , repair all areas of leakage before driving the vehicle.

Maximum Allowable Service Brake Air Leakage
Description	Air Leakage in psi (kPa) Per Minute
Description	Released	Applied
Truck or Tractor Only	2 (14)	3 (21)
Truck or Tractor w/Single Trailer	3 (21)	4 (28)
Truck or Tractor w/Two Trailers	5 (35)	6 (42)

Table 11.4, Maximum Allowable Service Brake Air Leakage

26.

Inspect the seat belts and tether belts.

Inspect and maintain seat belts. When any part of a seat belt system needs replacement, the entire seat belt must be replaced, both retractor and buckle side. Any time a vehicle is involved in an accident, and the seat belt system was in use, the entire vehicle seat belt system must be replaced before operating the vehicle. Do not attempt to modify the seat belt system; doing so could change the effectiveness of the system. Failure to replace worn or damaged seat belts, or making any modifications to the system, may result in personal injury or death.

26.1

Check the web for fraying, cuts, extreme dirt and dust, or for severe fading from exposure to sunlight, especially near the buckle latch plate and in the D-loop guide area.

26.2

Check operation of the buckle, latch, Komfort Latch or Sliding Komfort Latch (if equipped), web retractor, and upper seat belt mount on the door pillar. Check all visible components for wear or damage.

26.3

Check the seat belt and tether belt connection points and tighten any that are loose.

27.

Test the service brakes.

27.

When starting to move the vehicle and before picking up speed, test the brakes with the foot pedal and parking brake control valve (yellow knob) to be sure they will bring the vehicle to a safe stop.

Weekly Post-Trip Maintenance Procedures

Battery posts, terminals, and related accessories contain lead and lead compounds, chemicals known to the State of California to cause cancer and reproductive harm. To prevent possible personal injury, always wash your hands after handling battery parts and related accessories.

Inspect the batteries and battery cables.

1.1

Access the batteries. Be sure the battery hold-down is secure. If it is loose, tighten the hold-down bolts; if it is broken, replace it.

1.2

If the battery is equipped with a built-in hydrometer, examine the hydrometer. If a green dot shows in the sight glass, the battery is sufficiently charged.

1.2

If the sight glass is dark, the charge is low and the battery must be recharged.

1.2

If the sight glass is clear, the battery has a low level of electrolyte and must be replaced.

Check the level of the wheel bearing lubricant in the hub cap at each end of the front axle.

If needed, fill the hubs to the level indicated on the hub cap. See Group 35 of the Heavy-Duty Trucks Maintenance Manual , for recommended lubricants.

IMPORTANT: Before removing the fill plug, always clean the hub cap and plug.

Examine the steering components.

See Fig. 11.15 . If repairs are needed, see Group 46 of the Heavy-Duty Trucks Service Manual for instructions, or take the vehicle to an authorized Freightliner dealer.

1. Steering Gear Mounting Bolt
2. Pitman Arm Pinch Bolt Nut
3. Drag Link Nut

Fig. 11.15, Steering Gear Fasteners

3.1

Check the mounting bolts and pitman arm nut for tightness.

3.2

Check the drag link nuts for missing cotter pins.

3.3

Inspect the steering driveshaft and steering linkage for excessive looseness, or other damage.

3.4

Tighten loose nuts, and have damaged parts replaced as needed.

Check the condition of the serpentine drive belt.

Look for signs of glazing, wear (frayed edges), damage (breaks or cracks), or oil contamination. If a belt is glazed, worn, damaged, or oil soaked, have the belt replaced, following the instructions in Group 01 of the Heavy-Duty Trucks Service Manual.

Do not drive with a serpentine belt that is visibly worn or damaged. If it fails, the lack of coolant flow could rapidly cause damage to engine components.

Check the drive belt for proper tension.

Use your index finger to apply force at the center of the belt free-span. See Fig. 11.16 . There is no adjustment for belt tension on engines with automatic belt tensioners. If there is not proper tension, have the belt tensioner replaced. See Group 01 of the Heavy-Duty Trucks Service Manual for instructions, or take the vehicle to an authorized Freightliner dealer.

A. Deflection
B. Belt Free-Span

Fig. 11.16, Checking Belt Tension

Monthly Post-Trip Maintenance Procedures

Clean the batteries.

1.1

Remove any corrosion from the hold-down and the top of the battery.

Take care to keep the vent plugs tight so that the neutralizing solution does not enter any of the battery cells and damage the battery.

1.2

Use a soda solution to neutralize the acid present, then rinse off the soda solution with clean water.

1.3

If the battery posts or cable terminals are corroded, disconnect the terminals from the posts. Clean them with a soda solution and a wire brush. After cleaning, connect the terminals to the battery posts, then apply a thin coat of petroleum jelly to the posts and terminals to help retard corrosion.

Inspect the radiator and heater hoses, including the clamps and support brackets.

2.1

Make sure the radiator inlet and outlet hoses are pliable and are not cracking or ballooning. Replace hoses that show signs of cracking, weakening, or ballooning.

2.2

Make sure the heater hoses are pliable and are not cracking or ballooning. Replace hoses that show signs of cracking, weakening, or ballooning.

2.3

Tighten hose clamps as necessary, but do not overtighten, as hose life can be adversely affected.

2.4

Be sure the hose support brackets are securely fastened. Make sure the hoses are not located near sources of wear, abrasion, or high heat.

IMPORTANT: Replace all hoses, including heater hoses, at the same time. Service-type knitted or braided yarn-reinforced neoprene hose is acceptable. Silicone hoses having an extended service life can be substituted for the reinforced neoprene type. See the Freightliner Service Parts Catalog or contact your Freightliner Dealer.

Check the steering wheel for excessive play.

3.1

With the front tires straight ahead, turn the steering wheel until motion is observed at the front wheels.

3.2

Align a reference mark on a ruler, then slowly turn the steering wheel in the opposite direction until motion is again detected at the wheels.

3.3

Measure the lash (free play) at the rim of the steering wheel. Excessive lash exists if steering wheel movement exceeds 2-1/4 inches (57 mm) with an 18-inch (450-mm) steering wheel.

3.3

If there is excessive lash, check the steering system for wear or incorrect adjustment of the linkage and steering gear before operating the vehicle.

Check the brake lining wear on all vehicles, including those with automatic slack adjusters. Proper brake operation is dependent on periodic maintenance and inspection of the brake linings.

4.1

Check that brake linings are free of oil and grease.

4.2

Inspect the thickness of the brake linings. If the axle assembly is equipped with a dust shield or backing plate, remove the inspection plugs. If any brake linings are worn to less than approximately 1/4 inch (6.4 mm) at the thinnest point, have the linings replaced on all brake assemblies on that axle. See Group 42 of the Heavy-Duty Trucks Service Manual for lining replacement instructions and camshaft end-play inspection.

4.3

Check the brake drums for wear and cracks.

4.4

Check that the inspection plugs in the dust shields or backing plates, if so equipped, are installed.