Pretrip Inspection and Daily Maintenance
Pretrip Inspection Checklist
The following pretrip inspection checklist helps ensure that the vehicle components are in good working condition before each trip.
Pretrip inspections cannot be performed in a short period. In checklist form, the sequence below may seem to be overly time-consuming. However, careful pretrip inspections save time by eliminating stops later to adjust items overlooked or forgotten.
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.
Each checklist step corresponds with detailed instructions found under "Pretrip Inspection and Daily Maintenance Procedures." If any system or component does not pass this inspection, it must be corrected before operating the vehicle. See the Business Class® Trucks Service Manual for repair procedures, and the Business Class® Trucks Maintenance Manual for lubricant recommendations, specifications, and maintenance intervals and procedures.
NOTE: Apply the parking brakes and chock the tires.
1.
Drain the air brake system air reservoirs if equipped.
2.
Inspect the batteries and battery cables.
3.
Check the fluid level in the windshield washer reservoir.
4.
Check the front hub lubricant level (if equipped with oil-lubricated wheel bearings).
5.
Tilt the hood. Examine the steering gear components.
6.
Check the power steering hoses for chafing.
7.
Check the coolant level in the surge tank sight glass and check the radiator and air-to-air aftercooler cooling fins for clogging or damage.
7.
Check the radiator for coolant leaks.
8.
Check the condition of the coolant hoses and heater hoses.
9.
Check the condition of the drive belts.
10.
Inspect the engine for fuel, oil, and coolant leaks.
11.
Inspect the engine and chassis wiring.
12.
Inspect the air intake system for leaks or damage. Check the intake-air restriction indicator if it is mounted on the air intake system.
13.
Check the fluid level in the hydraulic brake fluid reservoir if equipped.
14.
Check the fluid level in the hydraulic clutch fluid reservoir if equipped.
15.
Check the engine oil level.
16.
Check the oil level in the automatic transmission if equipped.
17.
Check the fuel water separator (if equipped) for contaminants.
18.
Close the hood and engage the hood hold-down latches.
18.
Close the drain valves on the air brake system air tanks.
19.
Inspect the fuel tank(s) and fuel line connections. If so equipped, be sure that the fuel tank shutoff valves are open.
20.
Check the fuel level in the fuel tank(s) and be sure that the fuel cap vent area is clean. If so equipped, check the fuel/water separator for leaks. If needed, prime the fuel tank system.
21.
If so equipped, check the transmission oil cooler for debris and for leaks.
22.
If so equipped, inspect the fifth wheel and check it for adequate lubrication.
23.
Inspect the front and rear suspension components, including the springs, shocks, and suspension brackets.
24.
Clean the headlights, rearview and downview mirrors, and the outside of the windshield and all window glass. Check the condition of the windshield wiper arms and blades.
25.
Clean the inside of the windshield, the gauges on the dash, and all window glass.
26.
Check for excessive play at the steering wheel.
27.
Adjust the driver's seat, then align the rearview and downview mirrors.
28.
On mechanical clutch linkages (if equipped), check the clutch pedal free-travel.
29.
Check the seat belts for secure mounting and for damage.
30.
Check the cab interior for loose items and secure or remove them.
31.
Check the air restriction indicator if it is dash mounted.
32.
Turn on the ignition and start the engine. Be sure that the air- and oil-pressure warning systems, if equipped, are operating. Leave the engine running.
33.
Make sure that the electric horn and air horn, windshield wipers and washer, heater and defroster, and mirror heat, if so equipped, are operating properly.
34.
Check the operation of the backup alarm if so equipped.
35.
Turn on the lights. Check the operation of all gauge lights and interior lights. Leave the lights on.
36.
On tractor-trailer combinations, inspect the 7-way trailer cable receptacle(s) for good connections.
37.
If not already done, hook the trailer(s) to the vehicle and inspect the trailer system.
38.
Make sure that all of the lights are working, including the brake lights, fog lights (if so equipped), high- and low-beam headlights, turn signals, clearance lights, and four-way flashers. Check the condition of the reflectors. Turn the lights off.
39.
Check the outer surfaces of the hood, cab, and trailers for visible surface breaks and damage. Make sure that the trailer doors are secure.
40.
Inspect the air brake components (if equipped), including the brake chamber pushrods, air reservoirs, and air lines.
41.
Check brake lining wear on vehicles with air brakes.
42.
Make sure that the brakes are adjusted on all axles.
43.
Check the tire inflation pressures and inspect each tire for bulges, cracks, cuts, and penetrations. Check tire wear.
44.
Check for indications of loose wheel nuts or rim nuts and examine each rim and wheel component.
45.
Check the air brake system for proper operation.
46.
Test the service brakes before leaving the lot.
47.
Test the parking brakes on a 20-percent grade.
Pretrip Inspection and Daily Maintenance Procedures
Whenever equipment requires adjustment, replacement, repair, addition of lubricants, or a change of lubricants, see the Business Class® Trucks Service Manual for repair procedures and specifications, and the Business Class® Trucks Maintenance Manual for lubricant recommendations, specifications, and maintenance intervals and procedures.
1.
Drain the air brake system air reservoirs if equipped.
1.
Air reservoirs serve as storage tanks for compressed air. They collect water condensed from the air and small amounts of oil from the air compressor. Water and oil normally enter the reservoir in the form of vapor because of the heat generated during compression.
1.
After the water and oil condense, they collect near the tank drain valves. Drain the resulting emulsion as follows:
WARNING
NOTE: If the air tanks are not equipped with automatic drain valves, they must be drained daily. If they are equipped with automatic drain valves, they must be drained in this same manner at least once a week.
1.1
Open the wet tank valve (the drain cock or pull-chain drain located on the forward end of the supply air reservoir, which is connected directly to the air compressor). Block the valve open.
WARNING
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 which 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.
2.
Inspect the batteries ( Fig. 9.1 ) and battery cables as follows:
- 1. Batteries
Fig. 9.1, Battery Location
WARNING
2.1
Open the driver's door to access the batteries under the cab floor. Be sure that the battery hold-down is secure. If it is loose, tighten the hold-down bolts; if it is broken, replace it.
CAUTION
2.2
Remove any corrosion from the hold-down and the top of the battery. Use diluted ammonia or a soda solution to neutralize the acid present, then rinse off the ammonia or soda solution with clean water.
2.2
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.
3.
Check the fluid level in the windshield washer reservoir.
3.
Open the passenger's door to access the reservoir under the cab floor. Add washer fluid as needed.
WARNING
4.
Check the front hub lubricant level (if equipped with oil-lubricated wheel bearings).
4.
Observe the level of the wheel bearing lubricant in the hub cap at each end of the front axle and if needed, fill the hubs to the level indicated on the hub cap. See Group 33 of the Business Class® Trucks Maintenance Manual for recommended lubricants.
IMPORTANT: Before removing the fill plug, always clean the hub cap and plug.
5.
Tilt the hood. Examine the steering gear components.
5.
Examine the steering gear mounting bolts ( Fig. 9.2 ), pitman arm nut, and the drag link nuts for tightness. Be sure that the steering driveline and the U-joints are in roadworthy condition, without cracks, breaks, looseness, or other damage. Tighten loose nuts, and replace damaged parts as needed. See Group 46 of the Business Class® Trucks Service Manual .
5.
NOTE: On right-hand-drive vehicles, a linkage system runs from the steering driveline to the steering gear on the left-hand frame rail.
- 1. Steering Gear Mounting Bolts
- 2. Pitman Arm Pinch Bolt Nut
Fig. 9.2, Steering Gear (TAS series shown)
6.
Check the power steering hoses for chafing.
6.
Check for leakage around the fittings. Replace any damaged hoses and tighten all fittings to stop leakage.
CAUTION
7.
Check the coolant level in the surge tank sight glass. See Fig. 9.3 . Check the condition of the radiator fins, the A/C condenser, and the charge air cooler (as equipped).
7.
If the coolant is low, check the amount of antifreeze protection. If the protection is adequate, add a 50/50 mixture of water and antifreeze. If additional protection is needed, add antifreeze only. Add until the level is at the bottom of the surge tank fill neck.
7.
Good airflow through the radiator core and air-to-air aftercooler core is essential for proper engine cooling. The cores allow air passage, but form a particle barrier which tends to collect insects and airborne debris.
7.
Inspect for clogged fins. Use compressed air or water directed from the fan side of the core to backflush any material restricting airflow.
7.
On vehicles equipped with air conditioning and/or a charge air cooler, also inspect and clean these components. If clogged, the airflow through the radiator could be restricted.
7.
Straighten bent or damaged fins to permit airflow across all areas of the cores.
7.
Repair or replace the radiator if it is leaking. See Group 20 of the Business Class® Trucks Service Manual for instructions.
- 1. Sight Glass
Fig. 9.3, Surge Tank with Sight Glass
NOTE: When traveling through areas of high insect concentrations, it may be necessary to clean the exterior of the radiator or aftercooler core as often as every 200 miles (320 km).
8.
Check the condition of the coolant hoses and heater hoses.
8.
Make sure that the radiator inlet and outlet coolant hoses and heater hoses are pliable and are not cracking or ballooning. Replace hoses that show signs of cracking, weakening, or ballooning. Replace all hoses, including heater hoses, at the same time. Service-type knitted or braided yarn-reinforced neoprene hose is acceptable.
8.
Silicone hoses, having an extended service life, can be substituted for the reinforced neoprene type. See the Service Parts Catalog or contact your Freightliner Dealer.
8.
Tighten hose clamps as necessary, but do not overtighten as hose life can be adversely affected.
8.
Be sure that the hose support brackets are securely fastened. Make sure that the hoses are not located near sources of wear, abrasion, or high heat.
9.
Check the condition of the drive belts.
9.
Check the fan belt(s), alternator belt, and refrigerant compressor belt for signs of glazing, wear (frayed edges), damage (breaks or cracks), or oil contamination. If a belt is glazed, worn, damaged, or oil soaked, replace the belt following the instructions in Group 01 of the Business Class® Trucks Service Manual .
9.
Check all of the belts for proper tension. Use your index finger to apply approximately 25 pounds (11 kg) of force at the center of the belt free-span. See Fig. 9.4 . Deflection should be one belt thickness per 1 foot (300 mm) of belt free-span. If the tension is more than or less than this value, measure it with a belt-tension gauge and adjust it to the proper tension. See Group 01 of the Business Class® Trucks Service Manual for instructions.
- A. Deflection
- B. Belt Free-Span
Fig. 9.4, Checking Belt Tension
NOTE: On Cummins engines, a belt tensioner automatically adjusts the fan and alternator belt to the correct tension. If the belt slips, repair or replace the tensioner. For instructions, see the Cummins Shop Manual B Series Engines.
10.
Inspect the engine for fuel, oil, and coolant leaks.
10.
Correct any leaks found.
11.
Inspect the engine and chassis wiring.
11.
Inspect the engine and chassis for loose wiring, chafed insulation, and damaged or loose hold-down clamps. Tighten loose wires or hold-down clamps; replace damaged wiring or clamps.
12.
Check the air intake system for leaks or damage.
12.
Check the intake-air restriction indicator to determine if the air cleaner filter element needs to be changed. Replace the filter element if the yellow signal stays locked at 25 inH2O for Cummins engines or 20 inH2O for Mercedes-Benz engines. See Group 09 of the Business Class® Trucks Service Manual for filter element replacement instructions.
12.
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 replace damaged components. Make sure that the piping system is airtight so that all of the intake air passes through the air cleaner.
CAUTION
NOTE: After replacing the filter element, reset the restriction indicator by pressing the reset button.
13.
Check the fluid level in the hydraulic brake fluid reservoir ( Fig. 9.5 ) if equipped.
13.
If needed, fill the reservoir to the flange that surrounds the reservoir. Use only heavy-duty brake fluid, DOT 3.
- A. Open caps and check fluid level.
- B. Fill to this level.
Fig. 9.5, Hydraulic Brake Fluid Reservoir
14.
Check the fluid level in the clutch fluid reservoir ( Fig. 9.6 ).
14.
The reservoir is full when the fluid level is at the MAX mark. The fluid level must always be above the MIN mark. Use only heavy-duty brake fluid, DOT 3, in the hydraulic-clutch system.
- 1. Clutch Fluid Reservoir
Fig. 9.6, Check Clutch Fluid Level
15.
Check the engine oil level ( Fig. 9.7 ).
15.
The oil level should show between the upper and lower marks on the dipstick. Add enough oil to bring the level up to the operating range. See the engine manufacturer's operation and maintenance manual for recommended lubricants and capacities.
Fig. 9.7, Engine Oil Level Checking
CAUTION
16.
Check the oil level in the automatic transmission if equipped.
16.
NOTE: The fluid must be warm to ensure an accurate check. The fluid level rises as temperature increases.
16.
With the vehicle on a level surface, check the oil level (the dipstick is next to the windshield washer reservoir) in the transmission using one of the following procedures:
16.
Hot Check
Operate the transmission in a Drive (D) range until normal operating temperature, 160 to 200°F (71 to 93°C), is reached.
Park the vehicle. Shift to Neutral (N) and apply the parking brake. Let the engine run at idle.
Wipe the dipstick clean and check the fluid level. A safe operating level is any level within the HOT RUN (upper) band on the dipstick.
If the fluid is not within this range, add or drain fluid as needed to bring the level to the top of the HOT RUN band. See the Business Class® Trucks Maintenance Manual for fluid types and capacities.
Cold Check
A cold check may be made when the sump temperature is 60 to 104°F (15 to 40°C).
Run the engine for at least one minute to clear the fluid system of air.
With the engine running, wipe the dipstick clean and check the fluid level. Any level within the COLD RUN (lower) band is satisfactory for operating the vehicle. If the level is not within the COLD RUN band, add or drain fluid until it reaches the middle of the COLD RUN band.
Perform a hot check at the first opportunity after normal operating temperature, 160 to 200°F (71 to 93°C), is reached.
17.
Check the fuel water separator (if equipped) for contaminants.
17.
With the engine shut down, partially open the drain valve under the collection bowl and drain water and contaminants as needed.
18.
Lower the hood and engage the hood hold-down latches.
19.
Inspect the fuel tank(s) and fuel line connection. If equipped, be sure that the fuel tank shutoff valves are open.
19.
Replace leaking fuel tanks. Repair or replace any lines or connections that are leaking. For procedures, see Group 47 of the Business Class® Trucks Service Manual .
19.
If equipped with fuel tank shutoff valves, be sure that the valves are fully open.
WARNING
20.
Check the fuel level in the tank(s) and be sure that the fuel cap vent area is clean. Check the fuel/water separator (if equipped) and if needed, prime the fuel tank system.
WARNING
IMPORTANT: Use only low-sulfur diesel fuels. Low-sulfur diesel fuels have a maximum 0.05 percent sulfur content compared to a 0.26 to 0.30 percent sulfur content for other fuels. Failure to use low-sulfur diesel fuels may void the warranty on emission components.
20.1
To keep condensation to a minimum, fill the fuel tanks at the end of each day, but not to more than 95 percent of liquid capacity. Select the proper grade of fuel as specified by the engine manufacturer.
WARNING
20.2
Always strain or filter fuel before putting it into the tanks. This will lengthen the life of the engine fuel filter and reduce the chances of dirt entering the engine.
20.3
Before installing the fuel cap, check the vent line for debris. Clean the area around the fuel tank cap with a rag, or if necessary, clean the cap with solvent.
CAUTION
IMPORTANT: Before doing any of the following procedures, make sure that there is an adequate amount of fuel in the tank(s). Do not fill the tank(s) to more than 95 percent of liquid capacity.
20.4
On vehicles equipped with a single tank, prime the fuel system if needed. On vehicles with dual tanks, go to the next substep.
20.4
If the engine is equipped with a priming pump, do the following:
20.4
Unlock and operate the engine's priming pump plunger until resistance is felt.
20.4
Push the plunger in and tighten it by hand.
20.4
Start the engine. If it doesn't start, more priming is needed. Once the engine has started it may run rough. If this occurs, run the engine at low idle until it runs smoothly.
20.4
If the engine is not equipped with a priming pump, do the following:
20.4
Remove the fuel tank cap.
20.4
Loosen the fuel supply line at the fuel transfer pump.
20.4
Partially cover the fuel tank opening with your hand. Using an air hose, apply no more than 5 psi (35 kPa) air pressure to the fuel tank and look for a constant fuel flow at the loosened fuel supply line.
20.4
Remove the air hose and tighten the fuel supply line.
20.4
Start the engine. Once the engine has started, it may run rough. If this occurs, run the engine at low idle until it runs smoothly.
IMPORTANT: To prevent fuel loss or entry of air into a fuel line, make sure that all fuel line connections are tight.
20.5
On vehicles equipped with dual tanks and single suction and return lines (with crossover line), prime the fuel system if needed.
20.5
Use the same procedure provided in the previous substep for vehicles equipped with a single tank. Use the procedure on the tank equipped with the supply line.
20.5
21.
If equipped, check the transmission oil cooler for debris and for leaks.
21.
Remove debris and repair leaks as needed.
22.
If so equipped, inspect the fifth wheel and check it for adequate lubrication.
WARNING
22.1
If the vehicle is a truck-trailer combination, be sure that the trailer hitch is locked and that the safety cable or chains are connected. Be sure that air hoses and the light cable are connected.
WARNING
22.2
If the vehicle is a tractor-trailer combination, check that the fifth wheel lock mechanism is locked to the trailer kingpin. See Chapter 8 for instructions.
WARNING
NOTE: For adjustment and replacement instructions, see Group 31 of the Business Class® Trucks Service Manual .
22.3
With the trailer unhooked from the tractor, inspect the fifth wheel (daily) for the following conditions:
Loose nuts or broken bolts on the fifth wheel assembly, slider mechanism, and mounting brackets. Replace broken bolts and tighten loose nuts.
Cracks or wear on the fifth wheel assembly and mounting brackets. Replace each damaged or worn component.
Incorrect jaw locking action and cracks or wear on the jaw locking mechanism. Replace the mechanism if cracked or worn; repair it if the jaw locking action is incorrect.
Gouges or wear on the fifth wheel plate. Replace the plate if damaged or worn.
Fatigue or cracking of welds, which must be repaired according to the manufacturer's specifications.
WARNING
22.4
Lubricate the fifth wheel top plate and other grease points at least once a week, and more often in severe service.
22.4
Before connecting the fifth wheel to the trailer kingpin, always be sure that the fifth wheel plate is completely lubricated with chassis grease.
22.5
Clean all foreign material from the fifth wheel top plate. Lubricate the top plate surface, pickup ramps, and mounting bracket pivot pins using a waterproof or multipurpose chassis lubricant. Lubricate the jaw mechanism on all units except the Fontaine 5000 series fifth wheel. (Fontaine recommends that jaws and wedges remain dry to avoid accumulation of abrasive matter.)
23.
Inspect the front and rear suspension components, including the springs, shocks, and suspension brackets.
23.
Check for broken spring leaves, loose U-bolts, cracks in the suspension brackets, and loose fasteners in the spring hangers and shackles. Inspect the shock absorbers for loose fasteners and leaks.
23.
Tighten all loose fasteners and replace any component that is worn, cracked, or otherwise damaged.
WARNING
WARNING
24.
Clean the headlights, rearview and downview mirrors, and the outside of the windshield and all window glass. Check the condition of the windshield wiper arms and blades.
24.
Clean the windshield and side windows with a long-handled or telescoping window cleaning device and standard cleaning solutions. Stand only on the ground or on a stepladder or elevated walkway. The cab entry/exit steps and handholds are not designed for this purpose. The tires, fenders, fuel tanks, engine, and other under-hood components do not have adequate gripping surfaces and handholds.
24.
Access rear windows on tractors from the deck plate. Place the cleaning materials on the deck plate first so that your hands are free to climb up and down from the vehicle. If no deck plate is available, clean the rear windows using the same procedures as in the previous paragraph for cleaning the windshield and the side windows. Do not use the fuel tanks as a work platform.
24.
Be sure that the windshield wiper blades are tensioned against the windshield. Inspect the wiper blades for damage and deteriorated rubber. Replace the wiper arms if the wiper blades are not tensioned against the windshield. Replace damaged or deteriorated wiper blades.
WARNING
25.
Clean the inside of the windshield, the gauges on the dash, and all window glass.
26.
Check the steering wheel for excessive play.
26.
With the front tires pointed straight ahead, turn the steering wheel until motion is observed at the front wheels. 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. Measure the lash (free play) at the rim of the steering wheel. See Fig. 9.8 .
26.
Excessive lash exists if steering wheel movement exceeds 4-3/4 inches (121 mm) with an 18-inch (470-mm) steering wheel. If there is excessive lash, check the steering system for wear or incorrect adjustment of the linkage and steering gear before operating the vehicle.
- A. Lash Area
Fig. 9.8, Measuring Lash at the Steering Wheel
27.
Adjust the driver's seat, then align the rearview and downview mirrors.
28.
Check the clutch pedal free-travel.
28.
The main indicator for assessing clutch wear is clutch pedal free-travel. Clutch pedal free-travel is a decreased resistance felt at the top of the clutch pedal stroke. With the clutch pedal in this range, the clutch is fully engaged and the only resistance to clutch pedal movement is return spring tension. Clutch pedal free-travel should be approximately 1-1/2 to 2 inches (38 to 51 mm). See Fig. 9.9 . If the clutch pedal free-travel is less than 3/4 inch (19 mm), the clutch must be adjusted internally. For instructions, see Group 25 of the Business Class® Trucks Service Manual .
- A. About 1-1/2 to 2 Inches (38 to 51 mm)
Fig. 9.9, Check Clutch Free Pedal
CAUTION
29.
Inspect the seat belts and tether belts (if so equipped). See Fig. 9.10 .
WARNING
NOTE: When any part of a seat belt system needs replacement, the entire seat belt must be replaced, both retractor and buckle side.
29.1
Check the web for fraying, cuts, or extreme wear, especially near the buckle latch plate and the D-loop guide area.
29.2
Check the web for extreme dirt or dust and for severe fading from exposure to sunlight.
29.3
Check the buckle and latch operation and for wear or damage.
29.4
Check the Komfort Latch function and for cracks or other damage.
29.5
Check the web retractor function and for damage.
29.6
Check the tightness of the mounting bolts and tighten any that are loose.
- 1. Worn Web
- 2. Web
- 3. Buckle
- 4. Komfort Latch
- 5. Retractor
- 6. Tether Belt
Fig. 9.10, Seat Belt Inspecting
30.
Check the cab interior for loose items and secure or remove them.
31.
Check the air restriction indicator if it is dash mounted.
31.
Use the same procedure provided for systems with the indicator mounted on the air intake system.
32.
Start the engine and make sure that the oil-pressure and air-pressure warning systems are working.
32.
When the engine is started, oil-pressure and air-pressure warnings will come on until the oil pressure rises above a preset minimum and the air pressure in both the primary and secondary air reservoir systems goes above 64 to 76 psi (441 to 524 kPa). If the air pressure in both systems is above 64 to 76 psi (441 to 524 kPa) when the engine is started, test the low pressure warning system by lowering the pressure to below this range or until the warning system comes on.
32.
If the warning systems do not come on when the ignition is turned on, repair the systems.
CAUTION
33.
Make sure that both the electric horn and the air horn work. Then check the wiper and washer control. During cold weather, check the operation of the heater and defroster controls and, if equipped with optional mirror heat, turn on the mirror heat switch and make sure that the system is working.
33.
These devices must be in good working order for safe vehicle operation. If they are not working, repair them before trip departure.
34.
Check the operation of the backup alarm if so equipped.
35.
Check the operation of all gauge lights and interior lights.
35.
Turn on the headlights, dash lights, and four-way flashers, and leave them on. Check the operation of the dome light.
35.
If any of the gauge bulbs, the switch panel label bulb, the dome light bulb, or the right- and left-turn indicator bulbs are not working, replace them.
36.
On tractor-trailer combinations, inspect the 7-way trailer cable receptacle(s) for good connections.
36.
Clean and grease the 7-way socket and plug regularly, especially in regions where magnesium chloride or calcium chloride are used as road de-icers. These chemicals are highly corrosive to brass and copper, the base materials for the contact pins used in the 7-way receptacles. Clean the socket and plug with a plug brush and apply a moderate amount of dielectric grease to both the socket and plug pins. See Group 15 of the Business Class® Trucks Maintenance Manual for an approved dielectric grease.
37.
Hook the trailer(s) to the vehicle and inspect the trailer system.
37.
Whether or not the trailer was already hooked to the vehicle, check the following:
WARNING
37.1
Make sure that all fifth wheel connections are engaged and locked. Check that all connections to the dolly or trailer hitch and safety chains are secure.
37.2
Make sure that the gladhands in front of each trailer are engaged and that all air hoses are properly suspended.
37.3
Make sure that the air shutoff valves are turned on and that air is available to the lines on the trailer(s).
37.3
Make sure that the air shutoff valve at the back of the last trailer is turned off.
37.4
Make sure that all light cables are connected and correctly suspended.
37.4
Check that all trailer lights are working.
37.5
On semi-trailers, make sure that the landing gear supports are raised and that the handles are secure.
37.5
See the trailer manufacturer's detailed trailer inspection procedures for additional information.
38.
Make sure that all of the lights are working.
38.
Be sure that the brake lights, taillights, side marker lights, fog lights (if so equipped), headlights, signal lights, and clearance and identification lights are working and are clean. See Fig. 9.11 . Test the high beams and the low beams of the headlights.
38.
Replace light bulbs or sealed beam units that are not working.
38.
Be sure that all reflectors and lenses on the tractor and trailer(s) are in good condition and are clean. Replace any broken reflectors or lenses. Turn the lights off.
- 1. Headlight
- 2. Signal Light
- 3. Side Marker Light and Reflector
- 4. Clearance Light
- 5. Identification Lights
- 6. Fog Light
Fig. 9.11, Exterior Light Locations
39.
Check the outer surfaces of the hood, cab, and trailers for visible surface breaks and damage. Make sure that the trailer doors are secure.
40.
Inspect the air brake components (if equipped), including the brake chamber pushrods, air reservoirs, and air lines.
40.
Look for worn pins on brake chamber pushrods, and missing or damaged cotter pins on the brake chamber pushrod pins. Replace worn pins and install new cotter pins if necessary.
40.
Check for rusted connections, missing snap rings, and damaged camshaft grease seals. Repair or replace damaged or missing parts. Check the air reservoir band fasteners. Make sure that the outside surfaces of the reservoirs are painted to prevent corrosion damage. Inspect the reservoir surfaces for damage, such as cracks and dents. Replace corroded or damaged reservoirs with new ones. Do not repair damaged reservoirs. Old or used reservoirs are not acceptable as replacements. If a reservoir requires replacement, see Group 42 of the Business Class® Trucks Service Manual for instructions.
40.
Inspect the front air brake lines for leaks at the fitting where the lines enter the air chamber.
40.
With an assistant, turn the wheels to full lock in one direction and hold down the service brake pedal. Carefully inspect the front brake air lines where the lines enter the air chambers. Turn the wheels to full lock in the other direction, hold down the service pedal, and repeat the inspection.
40.
If there is a leak, replace the hose. See Group 42 of the Business Class® Trucks Service Manual for the hose replacement procedure.
40.
Inspect the air lines as follows:
40.1
Check the clearance between the hoses, exhaust manifold, and turbocharger or other hot spots. Excessive heat will cause the material in the hoses to deteriorate rapidly or become brittle. Provide at least six inches (150 mm) of clearance. More clearance is recommended if the hose is located above the heat source.
40.2
Check for kinks, dents, or swelling of the hoses. If a hose is damaged, replace it with the same size and type.
40.3
Do not route the hose on top of anything likely to be stepped on or walked on.
40.4
Check for damage to hoses located near moving parts, such as drivelines, trailer bodies, kingpins, suspensions, and axles. If the moving parts are catching or pinching the lines, correct as needed.
40.5
Check for hose damage caused by abrasion. If a hose is abraded, replace it. Check for the cause of abrasion, such as loose or damaged hose clamps. Repair or replace the clamps as needed.
40.6
Observe the hose cover condition, especially hoses exposed to water splash and ice. If any hose is dried out or ragged (the wire or liner is showing through the cover), replace the hose.
40.7
Inspect air tubing, especially tubing made of nylon. In cold weather, nylon tubing is sensitive to damage, such as nicks or cuts. Replace nicked or cut tubing, even if it is not leaking.
40.8
40.8
When a rubber hose does not meet minimum bend radius requirements, the outside may appear smooth even if the inner tube is kinked. Reroute the hose or replace it with one of adequate length if the bend radius is not within minimum specifications.
NOTE: Center of the hose bend radius should be well away from the fitting.
- A. Bend Radius
Fig. 9.12, Bend Radius
40.9
Check straight hose installations (those hoses that do not bend along their routings). Pressure changes can cause a hose to lengthen up to two percent or shorten up to four percent. A 100-inch (2540-mm) length of hose, for example, can contract to 96 inches (2440 mm). If the hose has no slack when it is exhausted of air, replace it with one of adequate length to avoid a possible blow-off from the fitting during vehicle operation.
40.10
Check for kinked or twisted hoses. A seven-percent twist in the hose can reduce its life by up to 90 percent. Also, a twisted hose under pressure tends to untwist. This could cause it to loosen the fitting. Reconnect hoses that are twisted.
41.
Check brake lining wear on vehicles with air brakes.
WARNING
IMPORTANT: It is necessary to check brake lining wear on all vehicles, including those with automatic slack adjusters.
Before checking lining wear when the wheel and hub assembly are removed, review the brake lining exposure warnings above.
To minimize the possibility of creating airborne brake lining dust, clean the dust from the brake drum, brake backing plate, and brake assembly using an industrial-type vacuum cleaner equipped with a high-efficiency filter system. Then, using a rag soaked in water and wrung until nearly dry, remove any remaining dust. Do not use compressed air or dry brushing to clean the brake assembly.
41.1
Apply the parking brakes. Chock the tires to prevent vehicle movement.
41.2
If the axle assembly is equipped with a dust shield or backing plate, remove the access plug from the dust shield or backing plate.
NOTE: If unable to accurately measure the brake lining, remove the wheel and hub assembly for a thorough inspection.
41.3
Measure the brake lining thickness. If any of the brake linings are worn to less than 1/4 inch (6.5 mm) at the thinnest point, replace the linings on all brake assemblies on that axle.
NOTE: To replace the brake linings, see the applicable brake section in Group 42 of the Business Class® Trucks Service Manual .
41.4
If removed, install the access plug. Remove the chocks from the tires.
42.
Make sure that the brakes are adjusted on all axles.
42.
Adjust the brakes if necessary. See Group 42 of the Business Class® Trucks Service Manual for checking and adjusting procedures.
IMPORTANT: Brake checking and adjusting is necessary for all vehicles, including trucks equipped with automatic slack adjusters.
43.
Check the tire inflation pressures and inspect each tire for bulges, cracks, cuts, and penetrations. Check tire wear.
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 or inflation. Some rims and wheels are stamped with a maximum load and maximum cold inflation rating. See Group 40 of the Business Class® Trucks Service Manual for the correct tire inflation pressure for the vehicle load or consult the rim or wheel manufacturer if they are not stamped. If the load exceeds the maximum rim or wheel capacity, the load must be adjusted or reduced.
43.1
Check the inflation pressures of the tires before each trip using an accurate tire pressure gauge ( Fig. 9.13 ). Tires should be checked when cool. See Table 9.1 or Table 9.2 for the correct tire inflation pressure for the vehicle load. When traveling at unusual speeds, use Table 9.3 to adjust tire pressure. Be sure that valve stem caps are on every tire and that they are screwed on finger-tight. Inflate the tires to the applicable pressures if needed.
43.1
Overinflation gives the treaded surface of the tire a convex shape ( Fig. 9.14 ). This causes extreme tire wear in the middle part of the tire since this section is primarily in contact with the road.
43.1
Underinflation gives the tread surface a concave shape ( Fig. 9.14 ). This causes excessive tire wear on the outer edges of the tire since the outer edges are primarily in contact with the road.
Fig. 9.13, Check Tire Pressure
- A. Tire correctly inflated.
- B. Tire overinflated.
- C. Tire underinflated.
Fig. 9.14, Tire Inflation
|
Tire Load Limits, Bias Ply Tubeless Tires, at Various Cold Inflation Pressures (maximum 60 mph [97 km/h]) |
|||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Size |
Load Range Ply Rating |
Axle |
Pressure in psi (kPa) |
||||||||||||||
|
45 (311) |
50 (345) |
55 (380) |
60 (414) |
65 (448) |
70 (483) |
75 (517) |
80 (552) |
85 (586) |
90 (621) |
95 (655) |
100 (689) |
105 (724) |
110 (758) |
115 (793) |
|||
|
9–22.5 |
E–10 |
Front Rear |
— |
— |
3010 2960 |
3190 3120 |
3370 3270 |
3560 3410 |
3730 3550 |
— |
— |
— |
— |
— |
— |
— |
— |
|
9–22.5 |
F–12 |
Front Rear |
— |
— |
3010 2960 |
3190 3120 |
3370 3270 |
3560 3410 |
3730 3550 |
3890 3690 |
4050 3820 |
4210 3950 |
— |
— |
— |
— |
— |
|
10–22.5 |
E–10 |
Front Rear |
— 3120 |
— 3310 |
3560 3510 |
3770 3690 |
4000 3870 |
4210 4040 |
4410 — |
4610 — |
— |
— |
— |
— |
— |
— |
— |
|
10–22.5 |
F–12 |
Front Rear |
— 3120 |
— 3310 |
3560 3510 |
3770 3690 |
4000 3870 |
4210 4040 |
4410 4200 |
4610 4360 |
4790 4520 |
4970 — |
4970 — |
5150 — |
— |
— |
— |
|
11–22.5 |
F–12 |
Front Rear |
— |
— 3760 |
— 3970 |
4290 4180 |
4530 4380 |
4770 4580 |
4990 4760 |
5220 — |
5430 — |
5640 — |
5840 — |
6040 — |
6240 — |
6430 — |
6610 — |
|
11–22.5 |
G–14 |
Front Rear |
— |
— 3760 |
— 3970 |
4290 4180 |
4530 4380 |
4770 4580 |
4990 4760 |
5220 4950 |
5430 5120 |
5640 5300 |
5840 — |
6040 — |
— |
— |
— |
Table 9.1, Tire Load Limits, Bias Ply Tubeless Tires, at Various Cold Inflation Pressures (maximum 60 mph [97 km/h])
|
Tire Load Limits, Michelin Standard and Low Profile Radial Ply Tubeless Tires, at Various Cold Inflation Pressures (maximum 65 mph [105 km/h]) |
|||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Size |
Load Range Ply Rating |
Axle |
Pressure in psi (kPa) |
||||||||||||||
|
45 (311) |
50 (345) |
55 (380) |
60 (414) |
65 (448) |
70 (483) |
75 (517) |
80 (552) |
85 (586) |
90 (621) |
95 (655) |
100 (689) |
105 (724) |
110 (758) |
115 (793) |
|||
|
9R–22.5 |
F–12 |
Front Rear |
— |
— |
2860 2610 |
3090 2840 |
3318 3114 |
3503 3261 |
3700 3474 |
3913 3671 |
4050 3835 |
4308 4050 |
4500 4220 |
— |
— |
— |
— |
|
10R–22.5 |
F–12 |
Front Rear |
— |
— |
— |
— |
— |
— |
4255 3914 |
4490 4130 |
4725 4349 |
4963 4566 |
5150 4740 |
— |
— |
— |
— |
|
10R–22.5 |
G–14 |
Front Rear |
— |
— |
— |
— |
— |
— |
4255 3914 |
4490 4130 |
4725 4349 |
4963 4566 |
5150 4740 |
5430 4995 |
5510 5080 |
— |
— |
|
11R–22.5 |
G–14 |
Front Rear |
— |
— |
— |
— |
— |
— |
4693 4224 |
4950 4550 |
5215 4693 |
5470 4923 |
5755 5180 |
6040 5440 |
— |
— |
— |
|
11R–22.5 |
H–16 |
Front Rear |
— |
— |
— |
— |
— |
— |
4693 4224 |
4950 4550 |
5215 4693 |
5470 4923 |
5755 5180 |
6040 5440 |
6245 5620 |
6428 5880 |
6610 5950 |
|
235/80R 22.5 |
G–14 |
Front Rear |
— |
— |
— |
— |
3593 3395 |
3815 3594 |
4035 3814 |
4278 4035 |
4543 4278 |
4675 4410 |
— |
— |
— |
— |
— |
|
255/70R 22.5 |
H–16 |
Front Rear |
— |
— |
— |
— |
3385 3135 |
3598 3329 |
3810 3521 |
4023 3713 |
4235 3905 |
4448 4096 |
4652 4280 |
4805 4420 |
4940 4540 |
5273 4851 |
5510 5070 |
|
255/80R 22.5 |
G–14 |
Front Rear |
— |
— |
— |
— |
— |
4000 3695 |
4235 3910 |
4465 4135 |
4710 4355 |
4960 4575 |
5205 4810 |
— |
— |
— |
— |
|
275/80R 22.5 |
H–14 |
Front Rear |
— |
— |
— |
— |
4155 3680 |
4435 3920 |
4715 4168 |
4990 4425 |
5260 4675 |
5535 4930 |
5805 5175 |
6080 5415 |
6345 5650 |
6615 5883 |
6940 6175 |
|
275/80R 22.5 |
H–16 |
Front Rear |
— |
— |
— |
— |
4155 3680 |
4435 3920 |
4715 4168 |
4990 4425 |
5260 4675 |
5535 4930 |
5805 5175 |
6080 5415 |
6345 5650 |
6615 5883 |
6940 6175 |
Table 9.2, Tire Load Limits, Michelin Standard and Low Profile Radial Ply Tubeless Tires, at Various Cold Inflation Pressures (maximum 65 mph [105 km/h])
|
Variations in Load and Inflation Limits According to Speed |
||
|---|---|---|
|
Speed Range
mph (km/h) |
Inflation Pressure Increase in psi (kPa) |
Percent Increase/Decrease in Load |
|
70 to 75 (113 to 121) |
10 (69) |
–10 |
|
61 to 70 (98 to 113) |
10 (69) |
0 |
|
51 to 60 (82 to 97) |
0 |
0 |
|
41 to 50 (66 to 80) |
0 |
+9 |
|
31 to 40 (50 to 64) |
0 |
+16 |
|
21 to 30 (34 to 48) |
10 (69) |
+24 |
|
11 to 20 (18 to 32) |
15 (103) |
+32 |
Table 9.3, Variations in Load and Inflation Limits According to Speed
WARNING
43.2
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.
43.3
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.
43.4
Inspect the tires for bulges, cracks, cuts, or penetrations. A tire pressure check will assist in uncovering hidden damage. A weekly pressure loss of 4 psi (28 kPa) or more in a tire may indicate damage and the tire should be inspected and repaired or replaced.
43.5
Tires should also be inspected for oil contamination. Fuel oil, gasoline, and other petroleum derivatives, if allowed to contact the tires, will soften the rubber and destroy the tire.
43.6
If the tires are wearing irregularly, rotate them. If the front steering axle tires become irregularly worn, move them to the drive axle ( Fig. 9.15 ). Have the front axle alignment checked to determine the cause of irregular tire wear. In a dual assembly, if one tire wears faster than its mate, reverse the position of the two tires. See Fig. 9.16 .
43.7
Government regulations require the removal of front axle tires at 4/32-inch (3-mm) remaining tread depth and rear axle tires at 2/32-inch (1.5-mm) remaining tread depth. However, front axle tires may be rotated to the drive or trailer axles to use the remaining 2/32-inch (1.5-mm) tread rubber. See Group 40 of the Business Class® Trucks Service Manual for additional information on tire matching, spacing of dual tires, and causes of abnormal tire wear.
Fig. 9.15, Front Axle to Rear Axle Rotation
Fig. 9.16, Dual Assembly Rotation
44.
Check for indications of loose wheel nuts or rim nuts and examine each wheel component.
44.
Check the wheel nuts or rim nuts for indications of looseness. 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 Group 40 of the Business Class® Trucks Maintenance Manual for torque specifications and the correct tightening sequence.
44.
Examine the wheel assembly components (including rims, rings, flanges, studs, and nuts) for cracks, or other damage.
44.
See Group 33 and Group 35 of the Business Class® Trucks Service Manual for service procedures on the studs and hubs and see Group 40 of the Business Class® Trucks Service Manual for wheel and tire servicing. Replace broken, cracked, badly worn, bent, rusty, or sprung rings and rims. Be sure that the rim base, lockring, and side ring are matched according to size and type.
WARNING
CAUTION
45.
Check components of the air brake system for correct operation as follows:
45.1
Release the parking brakes on the vehicle by pushing in the parking brake control valve knob. Check the air governor cut-in and cut-out pressures. Run the engine at fast idle. The air governor should cut out the air compressor at approximately 125 psi (862 kPa). With the engine idling, make a series of foot valve applications. The air governor should cut in the air compressor at approximately 95 psi (655 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.
45.2
Check the air pressure buildup time as follows:
45.2
For vehicles without a trailer air brake hookup, release the parking brakes on the vehicle by pushing in the parking brake control valve knob.
45.2
45.2
With the air system fully charged to 125 psi (862 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 125 psi (862 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.
- 1. Parking Brake Control Valve Knob
- 2. Trailer Air Supply Valve Knob
Fig. 9.17, Parking Brake Valve and Trailer Air Supply Valve Knobs
45.3
Check the air pressure reserve. With the air system fully charged to 125 psi (862 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.
45.4
Check the air leakage in the system (on vehicles with a trailer air brake hookup, charge the trailer-brake system with air by pushing in the trailer air supply valve knob).
45.4
With the parking brakes applied, the transmission out of gear, and the tires chocked, charge the air system until cutoff pressure of 125 psi (862 kPa) is reached.
45.4
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.
45.4
Charge the air system until cutoff pressure of 125 psi (862 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.
45.4
If leakage exceeds the limits shown in Table 9.4 , repair all areas of leakage before driving the vehicle.
|
Maximum Allowable Service Brake Air Leakage |
||
|---|---|---|
|
Description |
Service Brakes Maximum Allowable Air Leakage in psi (kPa) Per Minute |
|
|
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 9.4, Maximum Allowable Service Brake Air Leakage
WARNING
45.5
On vehicles with a trailer air brake hookup, check the spring parking brake system by pushing in the trailer air supply valve knob to release the trailer parking brakes. Pull the parking brake control valve knob out. The trailer air supply valve knob must pop out immediately and the tractor and trailer spring parking brakes must both apply.
45.5
With a fully charged air system of 125 psi (862 kPa), push in the parking brake control valve knob. The tractor spring parking brakes should release. Push the trailer air supply valve knob in.
45.5
With the trailer air system charged to 125 psi (862 kPa), the trailer brakes (spring parking brakes, if so equipped, or service brakes) should release.
45.5
Pull the trailer air supply valve knob out. The trailer brakes should apply.
NOTE: For trailers not equipped with spring parking brakes, the trailer service brakes automatically apply when the trailer air supply valve knob pops out.
46.
Test the service brakes before leaving the lot.
46.
When starting to move the vehicle and before picking up speed, test the brakes with the foot valve and parking brake valve to be sure that they will bring the vehicle to a safe stop.
46.
If the vehicle has hydraulic brakes, depress the brake pedal, release the parking brake, and check that the brake system warning light goes off. If the warning light remains on after releasing the parking brake, correct the problem before driving off.
47.
Test the parking brakes on a 20-percent grade.
47.
Pull the parking brake control valve knob or apply the hand brake with the vehicle on a 20-percent grade. If the parking brakes do not hold the vehicle, repair the parking brake system.