Fuel Tank Bracket and Mounting Replacement (Cab/Chassis)

FUEL TANK BRACKET AND MOUNTING REPLACEMENT (CAB/CHASSIS)

TOOLS REQUIRED
J 45878 Combustible Gas Detector

REMOVAL PROCEDURE
1. Remove the CNG fuel tank.




2. Remove the fuel line hold-down clips (1,4).
3. Disconnect the fuel line at the fuel filter inlet (2).
4. Disconnect the fuel line at the high pressure regulator (HPR) inlet (3).
5. Remove the fuel lines from the vehicle.




6. Remove the fuel filter bracket mounting bolts (2,4)
7. Remove the fuel filter/fuel line assembly from the vehicle.




8. Partially drain the engine coolant. Refer to Draining and Filling Cooling System (w/RPO HP2) Draining and Filling Cooling System, Service and Repair
9. Loosen the hose clamps (2,6) enough to move the clamps away from the HPR coolant fittings.
10. Disconnect the HPR coolant hoses (3,5) from the HPR.
11. Pull the HPR coolant hoses through the tank mounting frame.
12. Disconnect the HPR fuel outlet line (4).




13. Remove the HPR fuel inlet fitting (6). Capture the filter spring (4), filter (3) and seal (2) that are located behind the inlet fitting.




14. Remove the HPR mounting nut (1) and washer.

IMPORTANT: Do not hold the HPR at the cover hex flange. As required, wedge a wrench between the HPR and the tank frame in order to keep the HPR from spinning in the bracket.

15. Remove the HPR from the mounting bracket.




16. Remove and discard the tank mounting plate to vehicle frame bolts and nuts (1,2).
17. Remove the CNG fuel tank mounting plate from the vehicle.

INSTALLATION PROCEDURE
1. Position the CNG fuel tank mounting plate onto the vehicle.




2. Install the tank mounting plate to the vehicle frame with new bolts and nuts (1,2).

NOTE: Refer to Fastener Notice in Service Precautions.

IMPORTANT: On vehicles equipped with a Type 4 fuel tank, ensure that the frame reinforcement plates are installed only on the forward two frame mount bolts.

Tighten the nuts to 110 N.m (81 lb ft).




3. Install the HPR assembly (8) to the mounting bracket.

IMPORTANT: Do not hold the HPR at the cover hex flange. As required, wedge a wrench between the HPR and the tank frame in order to keep the HPR from spinning in the bracket.

4. Install the HPR mounting nut (1) and washer.

Tighten the nut to 54 N.m (40 lb ft).




5. Install the filter spring (4), filter (3) and seal (2) into the HPR inlet port.
6. Install the HPR fuel inlet line fitting (6) with a new O-ring. Lubricate the O-ring with petroleum jelly.

CAUTION: Refer to Compressed Natural Gas (CNG) O-Ring Caution in Service Precautions.

Tighten the fuel line fitting to 48 N.m (35 lb ft).




7. Pull the HPR coolant hoses through the tank mounting frame.
8. Connect the HPR coolant hoses (3,5) to the HPR.
9. Install the HPR fuel outlet line (4) with a new O-ring. Lubricate the O-ring with petroleum jelly.

Tighten the fuel line fitting to 37 N.m (27 lb ft).




10. Install the fuel filter/fuel line assembly into the vehicle.
11. Install the fuel filter bracket mounting bolts (2,4).

Tighten the bolts to 12 N.m (9 lb ft).




12. Install the HPR fuel inlet line (3) with a new O-ring. Lubricate the O-ring with petroleum jelly.

Tighten the fuel line fitting to 37 N.m (27 lb ft).

13. Install the fuel filter inlet line (2) with a new O-ring. Lubricate the O-ring with petroleum jelly.

Tighten the fuel line fitting to 37 N.m (27 lb ft).

14. Install the fuel line mounting clips (1,4).

Tighten the check valve fuel line mounting clip bolt (4) to 12 N.m (9 lb ft).

15. Install the CNG fuel tank.
16. Fill the cooling system. Refer to Draining and Filling Cooling System (w/RPO HP2) Draining and Filling Cooling System, Service and Repair
17. Fill the CNG fuel system.
18. Start the engine and use the J 45878 in order to inspect for CNG fuel system leaks at each serviced fitting.