Daily Pretrip Inspection and Maintenance Procedures

c2 dm 14.02.001

Important: If any system or component does not pass this inspection, it must be corrected before operating the vehicle. Whenever equipment requires adjustment, replacement, and/or repair, see the Saf-T-Liner C2 School Bus Workshop Manual for procedures and specifications.

Complete the following inspection and maintenance procedures to ensure that vehicle components are in good working condition before each trip. A driver who 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 consistent basis, all daily, weekly, and monthly inspection and maintenance procedures should be performed before the trip.

Important: The pre- and post-trip checklists, inspections, and maintenance procedures detailed in this chapter are not all-inclusive . Refer to other component and body manufacturers' instructions for specific inspection and maintenance instructions, as well as local, state, and federal guidelines.

Drain the brake system air reservoirs (reservoirs without automatic drain valves only).
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. 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.
2. Exhaust the remaining air and moisture from the system by opening the drain cocks on the bottom of the remaining air reservoirs. Block the valves open.

Warning: Never remove the surge tank cap while the engine is operating or while the engine and radiator are still hot. Scalding fluid and steam can blow out under pressure if the cap is taken off too soon. Failure to follow these precautions could result in serious personal injury from heated coolant spray.

Caution: Use caution when working around the dash/body heater surge tank. The dash/body heater surge tank is metal and when the auxiliary heater is in use the surge tank will become very warm to the touch.

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

Check the engine coolant level in the radiator surge tank.

If the coolant is low, add a 50/50 mixture of water and antifreeze. Refer to the coolant label on the vehicle or the engine manufacturer’s service literature for approved coolants. Coolant used must be compatible with the engine manufacturer’s coolant specifications. For information regarding approved coolants on Cummins engines, refer to the Cummins Online website athttps://www.cummins.com/support/manualsor scan the QR code. See Fig. For information regarding approved coolants on Detroit™ engines, refer to the Detroit Diesel link on the DTNA TechLit website https://www.dtnatechlit.com/portal-public or scan the QR code. See Fig. Fill the surge tank with coolant to the FULL 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. See Fig..

Fig. 1, Cummins QR Code

Fig. 2, TechLit QR Code

Fig. 3, Surge Tank Fill Cap
Inspect the radiator and charge air cooler, including the radiator and heater hoses, clamps and support brackets.
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.
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.
3. Inspect and clean the condenser. If clogged, the condenser can restrict airflow through the radiator.
4. Check the radiator for leaks. If leaks are found, have the radiator repaired or replaced. See Group 20 of the Saf-T-Liner C2 School Bus Workshop Manual for instructions, or take the vehicle to an authorized Freightliner dealer for assistance.
5. Make sure the radiator inlet and outlet hoses are pliable and are not cracking or ballooning.
6. Make sure the heater hoses are pliable and are not cracking or ballooning.
7. Tighten hose clamps as necessary.
8. Ensure hose support brackets are securely fastened. Make sure hoses are not located near sources of wear, abrasion, or high heat.

Important: When replacing hoses, install service-type knitted or braided yarn-reinforced neoprene hose. Extended-service-life silicone hoses may also be used. See the Alliance Parts Catalog at www.alliancebrandparts.com or contact a Freightliner dealer.

Check the ground underneath the engine for fuel, oil, or coolant leaks. Correct any leaks found .
Inspect the air intake system for leaks or damage.
1. Push the reset button on the air intake restriction indicator located on the air cleaner, if equipped.
2. Check the air intake duct from the air cleaner to the engine intake. Make sure the duct components are secure and airtight.

Important: On engines that comply with EPA07 or newer regulations, use CJ-4 engine oil with less than 1% sulfated ash. Failure to use CJ-4 oil may void the warranty on emission aftertreatment components.

Notice: 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.

Check the engine oil level.
1. Park the vehicle on a level surface. Allow several minutes for the oil to drain back into the oil pan to ensure an accurate reading.
2. Pull out the dipstick and clean it with a paper towel or cloth, then push the dipstick back in all the way. Remove it again, keeping the tip down, and check the oil level.
3. If the oil is below the cross-hatched area, or the add mark, at the tip of the dipstick, add at least one quart (liter) of the recommended oil. See Fig. for diesel engines and Fig. for propane engines.
  For diesel engines that comply with EPA07 or newer regulations, use CJ-4 engine oil with less than 1% sulfated ash.
  
  For liquid propane gas (LPG) engines, use SAE 5W–30 oil that meets GM standard GM6094M and has the American Petroleum Institute (API) symbol. Do not use SAE 10W–40 or 20W–50.
Fig. 4, Oil Dipstick (diesel engine)

Oil should be within the cross-hatched area of the dipstick.

Fig. 5, Oil Dipstick (propane engine)

Notice: Failure to use the recommended oil can result in engine or aftertreatment component damage and will void the warranty.

If the vehicle is equipped with an automatic transmission, check the automatic transmission fluid level.
1. Operate the transmission in a Drive (D) range until normal operating temperature, 160 to 200°F (71 to 93°C), is reached.
2. With the parking brake applied, shift to Neutral (N). Let the engine run at idle.
3. 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. See Fig..
4. 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.
  Fig. 6, Automatic Transmission Dipstick Markings
Check for water in the fuel/water separator, if equipped.
1. Place a suitable container under the fuel/water separator.
2. If the engine is equipped with a built-in water separator, loosen the drain valve, and allow the water to run out. Close the drain valve, taking care not to overtighten it.
3. Alliance/Racor Models : Turn the drain plug counterclockwise to open it. See Fig..
  DAVCO Models : Remove the vent cap and open the drain. See Fig..
  Fig. 7, Alliance Fuel/Water Separator Assembly and Installation
  Fig. 8, DAVCO Fuel/Water Separator (Fuel Pro 482 shown)
4. Stop draining fluid when fuel begins to drain out.
  Alliance/Racor Models : Turn the drain plug clockwise to close it.
  
  DAVCO Models : Close the drain valve. Install and hand-tighten the vent cap.
Inspect the fuel tanks, fuel lines, and connections.
1. Ensure fuel tanks are secured to their mounting brackets and that the mounting brackets are secured to the frame.
2. Replace leaking fuel tanks.
3. If lines or connections are leaking or chafed, have them repaired or replaced.
4. If equipped with fuel tank shutoff valves, be sure the valves are fully open.

Warning: 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: On engines that comply with EPA07 or newer regulations, use ultralow-sulfur diesel (ULSD) with 15 ppm sulfur content or less. Failure to use ULSD fuel may void the warranty on emission components.

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.

On vehicles equipped with a diesel engine, be sure that the fuel cap vent area is clean.

Caution: Service and repair of the compressed natural gas (CNG) fuel system should only be performed by trained CNG service technicians. To prevent personal injury or damage to the fuel system, do not attempt repairs yourself.

Inspect the CNG vent cap, vent line and connection for visible signs of damage.

If the vent cap is damaged or missing, inspect the vent line for water or trash. Drain and clear any water or trash and install a new vent cap. See Fig..
Fig. 9, CNG Vent Cap Inspection
Inspect the front and rear suspension components, including springs, spring hangers, shocks, and suspension brackets.
1. Check for broken spring leaves, loose U-bolts, cracks in the suspension brackets, and loose fasteners in the spring hangers and shackles.
2. Inspect the shock absorbers for loose fasteners and leaks.
3. Tighten all loose fasteners and have any components replaced that are worn, cracked, or otherwise damaged.
4. On vehicles with air suspensions, check for leaks. Check air suspension components for cuts and bulges.

Warning: Do not replace individual leaves of a damaged front or rear suspension leaf spring assembly; replace the complete spring assembly. Visible damage, such as cracks or breaks, to one leaf causes hidden damage to other leaves. Replacement of only the visibly damaged part(s) is no assurance that the spring is safe. If cracks or breaks exist on front spring assemblies in either of the two top leaves, a loss of vehicle control could occur. Failure to replace a damaged spring assembly could cause an accident resulting in serious personal injury or property damage.

Push the reset button on the dash-mounted air intake restriction indicator, if equipped.
With the ignition switch in the OFF position, check the air-pressure warning system.
1. If not previously drained, drain the air reservoirs using moderate brake applications until pressure in both reservoirs is less than 70 psi (483 kPa).
2. Turn the ignition switch to the ON/RUN position. The ICU will complete a full gauge sweep and bulb check, and an audible warning will sound. Ensure the low air pressure lamp (BRAKE AIR) remains illuminated and an audible warning continues to sound after the gauge sweep is complete.
Make sure that the electric horn works.
Make sure all the exterior lights are working.
All exterior lights should be checked for proper operation. Clean the windshield, side, and rear windows (if equipped) with a long-handled or telescoping window cleaning device and standard cleaning solutions.
1. Turn the ignition switch to the ACCESSORY or ON/RUN position.
2. Make certain the service brake is not applied and the parking brake is set.
3. Press the pretrip inspection switch on the dash, shown in Fig., to begin the pretrip light inspection.
  The instrument cluster will beep rapidly for five seconds, and then begin a 10-second countdown, followed by a 2-second beep. The 10-second countdown period allows the operator to exit the bus before the pretrip light inspection begins. After the 2-second beep, the following exterior lights will flash simultaneously:
Fig. 10, Pretrip Light Inspection Switch
- amber warning lights (front and rear)
- red warning lights (front and rear)
- stop arm
- park lights (all)
- turn signals
- left and right headlights (low- and high-beam)
- crossing arm (may partially retract during flashing-off period)
- taillights
- brake lights
- back-up lights
  - The pretrip light inspection can be stopped by:
- turning the ignition switch to the OFF position;
- applying the service brake;
- releasing the parking brake.
Inspect the air brake chamber and the air brake chamber pushrods.

Note: Do not loosen or remove the parking brake clamp ring for any purpose. See Fig.. 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 Saf-T-Liner C2 School Bus Workshop Manual.

Visually inspect slack adjuster components.

Inspect the slack adjuster boot for cuts or tears. If the boot is damaged, have it replaced. See Fig..
Fig. 11, Parking Brake Chamber Clamp
Fig. 12, Automatic Slack Adjuster (typical)
Check tire inflation pressures.
Tires should be checked when cool. For inflation pressures and maximum loads (per tire) see the tire manufacturer's guidelines.
1. If a tire has been run flat or underinflated, check for possible wheel or tire damage before adding air.
  
  Keep compressed air reservoirs and lines dry during tire inflation. Use well-maintained inline moisture traps and service them regularly.
2. Inflate the tires to the applicable pressures if needed.
3. Be sure valve stem caps are on every tire and that they are screwed on finger-tight.

Important: Low-rolling resistance (LRR) tires minimize wasted energy as a tire rolls, thereby decreasing rolling effort and improving fuel efficiency. If tire replacement is necessary, replacement tires must meet or exceed the rolling resistance of the originally installed tires in order to maintain compliance with greenhouse gas and fuel efficiency regulations.

Contact your tire manufacturer/supplier to determine the rolling resistance of the originally installed tires. Visit www.epa.gov/smartway for additional information and resources.

Inspect the condition of all tires.
1. 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.
2. Inspect each tire for bulges, cracks, cuts, and penetrations.
3. Inspect each tire for oil contamination (petroleum derivatives will soften the rubber and destroy the tire).
Check the wheel nuts for indications of looseness. Examine each wheel component.
1. Remove all dirt and debris from the assembly. Rust streaks or metal build-up around stud holes, or out-of-round or worn stud holes, may be caused by loose wheel nuts.
2. Examine the wheel components (including studs and nuts) for cracks or other damage.
3. Make sure all wheel nuts are tightened. If tightening is necessary, use the tightening pattern in Fig. for 10-stud disc wheels and Fig. for 8-stud disc wheels to initially tighten the flange nuts to 50 to 100 lbf·ft (68 to 136 N·m). Then tighten the flange nuts to 450 to 500 lbf·ft (610 to 678 N·m).
  
  Fig. 13, Tightening Pattern, 10-Stud Disc Wheels
  
  Fig. 14, Tightening Pattern, 8-Stud Disc Wheels

Note: Vehicles operating under severe or adverse conditions should be checked more frequently.

Check the air brake system for proper operation.

Check the air governor cut-in and cut-out pressures. Start the engine and ensure the BRAKE AIR lamp goes out and the buzzer silences when pressure reaches approximately 70 psi (483 kPa) in both air reservoirs. The air governor should cut out at approximately 120 psi (827 kPa). For vehicles with an optional dryer reservoir module (DRM), the cut-out pressure is approximately 130 psi (896 kPa).
With the engine idling, apply the brake pedal several times. The air governor should cut in when pressure in the primary air reservoir (top air gauge) reaches approximately 100 psi (690 kPa).
Check the air pressure buildup time.
With the air system fully charged, make one full brake application and note the air pressure reading on the primary air gauge. Further reduce air pressure using moderate brake applications, then run the engine at governed rpm. Note the time that the pressure reaches the previously noted reading on the primary air gauge, then note the time that the air pressure reaches cut-out pressure.

If it takes longer than 30 seconds to reach cut-out pressure after the primary air gauge passes the previously noted pressure (noted after one full brake application), eliminate any leaks or replace the air compressor before operating the vehicle.
Check the air pressure reserve.
With the engine still off, make one full brake application and observe the pressure drop on the primary air gauge. If pressure drops more than 25 psi (172 kPa), eliminate any leaks before operating the vehicle.

Check the air leakage in the system.

With the parking brake applied, the transmission out of gear, and the air system fully charged, release the service brakes and shut down the engine. Wait one minute and note the air pressure drop in psi (kPa) per minute from the primary air reservoir.

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

Table 1, Maximum Allowable Service Brake Leakage

Maximum Allowable Service Brake Leakage
Brakes Released	Brakes Applied
2 psi/min. (14 kPa/min)	3 psi/min. (21 kPa/min)

Table 1, Maximum Allowable Service Brake Leakage

Test the parking brake on a 20 percent grade.
Apply the hand brake with the vehicle on a 20 percent grade (or a steep grade that the vehicle may normally be parked on). If the parking brake does not hold the vehicle, repair the parking brake system.
Inspect the operation of the Hydro-Max® brake booster, as follows.
1. With the engine off, depress the brake pedal. The warning light and buzzer should come on, and the electric motor should run.
2. Start the engine and allow the gauges to sweep. Depress the brake pedal. No warning lights, buzzer, or electric motor should come on.
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 clamps.

Note:

Saf-T-Liner C2 School Bus Driver's Manual

Daily Pretrip Inspection and Maintenance Procedures

Fig. 1, Cummins QR Code

Fig. 2, TechLit QR Code

Fig. 3, Surge Tank Fill Cap

Fig. 4, Oil Dipstick (diesel engine)

Fig. 5, Oil Dipstick (propane engine)

Fig. 6, Automatic Transmission Dipstick Markings

Fig. 7, Alliance Fuel/Water Separator Assembly and Installation

Fig. 8, DAVCO Fuel/Water Separator (Fuel Pro 482 shown)

Fig. 9, CNG Vent Cap Inspection

Fig. 10, Pretrip Light Inspection Switch

Fig. 11, Parking Brake Chamber Clamp

Fig. 12, Automatic Slack Adjuster (typical)

Fig. 13, Tightening Pattern, 10-Stud Disc Wheels

Fig. 14, Tightening Pattern, 8-Stud Disc Wheels

Table 1, Maximum Allowable Service Brake Leakage

Table 1, Maximum Allowable Service Brake Leakage