Freightliner Conventional Daily Pretrip Maintenance Procedures

Use this complete daily inspection and maintenance procedures to ensure that vehicle components are in good working condition before each trip.

MaintainX

10/08/2022

Freightliner Conventional Daily Pretrip Maintenance Procedures

Use this complete daily inspection and maintenance procedures to ensure that vehicle components are in good working condition before each trip.

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 con- dense, drain the resulting emulsion as follows:

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

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.

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

If the drained water is cloudy or oily, it may indicate a problem with the compres- sor. 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.

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 cur- rently 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 en- gine after refilling and check the level again when the engine is at operating temperature.

Fig. 11.1, Coolant Level Checking

Inspect the radiator and charge air cooler.

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.

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.

On vehicles equipped with air condition- ing, also inspect and clean the condenser. If clogged, the condenser can restrict air- flow through the radiator.

Check the radiator for leaks. If leaks are found, have the radiator repaired or re- placed. See Group 20 of the Heavy-Duty Trucks Service Manual for instructions, or take the vehicle to an authorized Freight- liner 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 dam- aged wiring or clamps.

Inspect the air intake system for leaks or damage.

Check the intake-air restriction indicator.

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.

Inspect the secondary or safety filter ele- ment 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.

Check the engine air intake piping from the air cleaner to the engine intake. In- spect the piping for loose connections, cracks, torn or collapsed hoses, punc- tures, and other damage. Tighten loose connections, and have damaged compo- nents replaced. Make sure the piping sys- tem 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.

Fig. 11.2, Oil Level Checking

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

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

Replace leaking fuel tanks.

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

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

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.

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.

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

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

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

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.

Fig. 11.3, Racor Fuel/Water Separator

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 bot- tom 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.

Fig. 11.4, Davco Fuel/Water Separator

Inspect the front and rear suspension compo- nents, including springs, spring hangers, shocks, and suspension brackets.

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 fas- teners and leaks.

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

On vehicles with air suspensions, check for leaks. Check air suspension compo- nents for cuts and bulges.

Clean the windshield, and the side and rear win- dows, then check the condition of the windshield wiper arms and blades.

Fig. 11.6, ConMet Fuel/Water Separator

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

Replace damaged or deteriorated wiper blades.

Check the oil- and air-pressure warning systems.

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

Start the engine, then check that the oil- and air-pressure warning systems are op- erating. 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.

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 pres- sure is 130 psi (896 kPa).

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.

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

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.

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

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

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.

Make sure all the exterior lights are working properly. Check that all the lights and reflectors are clean. See Fig. 11.7.

Fig. 11.7, Exterior Lights

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.

Test the high and low beams of the headlights.

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

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

Check tire inflation pressures using an accurate tire pressure gauge.

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

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.

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

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.

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

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

Check the tire tread depth. If tread is less than 4/32 inch (3 mm) on any front tire, or less than 2/32 inch (1.5 mm) on any rear tire, replace the tire.

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

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.

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

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

Fig. 11.9, Worn Stud Holes

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

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.

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

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

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

Fig. 11.12, Parking Brake Chamber Clamp

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

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

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.

Inspect the exterior surfaces of the cham- ber 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 Manualto replace any damaged parts.

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

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

Inspect the air brake lines.

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 be- come brittle. Provide at least 6 inches (150 mm) of clearance. More clearance is recommended if the hose is located above the heat source.

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

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.

Check for hose damage caused by abra- sion. 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.

Observe the hose cover condition, espe- cially 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.

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

Check for kinked or twisted hoses. A seven-percent twist in the hose can re- duce 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.

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.

Turn the wheels to full lock in one direc- tion 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.

Inspect the slack adjusters.

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

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

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

Fig. 11.13, Gunite Automatic Slack Adjuster

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

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

Fig. 11.14, Haldex Automatic Slack Adjuster

Check the air brake system for proper operation.

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

Run the engine at fast idle. The air gover- nor should cut out the air compressor at approximately 120 psi (827 kPa). With the engine idling, apply the brake pedal sev- eral 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.

Check the air pressure buildup time as follows.

With the air system fully charged to 120 psi (827 kPa), make one full brake appli- cation 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.

Check the air pressure reserve as follows. 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 elimi- nated before operating the vehicle.

Check the air leakage in the system as follows.

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

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

Charge the air system until cut-out pres- sure of 120 psi (827 kPa) is reached. With the parking brakes released and the ser- vice 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.

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

Table 11.4, Maximum Allowable Service Brake Air Leakage

Test the service brakes.

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.

Source: MaintainX (Community Member)