Fuel Tank: Testing and Inspection

Fuel Tank Mounting:

ON VEHICLE LEAK CHECK

NOTE:
- Before removing the fuel tank for a suspected leak, make sure the fuel hoses are not leaking onto the tank. Also, make sure fuel is not leaking around the fuel level meter assembly gasket.
- A visual inspection of the tank, and a leak-check of the fuel tank bladder are the only checks possible on-vehicle. If fuel is leaking from the tank, replace the tank and check for leaks.

PROCEDURE:

1. Place a dry chemical (Class B) fire extinguisher near the work area.
2. Relieve the fuel system pressure, refer to MAINTENANCE PROCEDURES/FUEL SYSTEM PRESSURE RELIEF.
3. Drain the fuel tank, refer to MAINTENANCE PROCEDURES/DRAINING FUEL TANK.
4. Disconnect the fuel feed hose, and cap tube on the fuel level meter assembly.
5. Disconnect the vapor vent hose between the fuel level meter assembly and the fuel tank "TEE" fitting at the "TEE."
6. Plug the hose and cap the open end of the "TEE" fitting.
7. Disconnect the vapor vent hose to the canister from the other side of the "TEE" fitting.
8. Connect a piece of hose to the open end of the tee fitting, and place the other end into a container of water.
9. Install the fuel filler cap.
10. Apply 7-10 kPa (1.0-1.5 psi) air pressure to the fuel return tube on the fuel level meter assembly.
- Continuous air bubbles appearing in the container indicate a leak in the bladder. A short burst of air bubbles is common at the start.
11. Replace the fuel tank if the bladder is leaking.

OFF THE VEHICLE LEAK CHECK

NOTE:
- "Off-Vehicle" leak check requires two sources of regulated air pressure.
- This check requires a fuel level meter assembly and fuel filler cap to be installed in the tank.

PROCEDURE:

1. Cap the fuel feed tube and vapor vent tube on the fuel level meter assembly.
2. Cap one end of the fuel tank "TEE" fitting.
3. Connect a piece of hose to the open end of the "TEE" fitting, and place the other end into a container of water.
4. Tighten the fuel filler cap.
5. Apply 7 to 10 kPa (1 to 1.5 psi) air pressure to the fuel return tube on the fuel level meter assembly.
- Continuous air bubbles appearing from the container indicates a leak in the bladder. A short burst of air bubbles is common at the start. Replace the fuel tank if the bladder is leaking.
- If no or only a short burst of bubbles appear, continue with the check.

CAUTION: Equal air pressure must be applied to the fuel return tube on the fuel level meter assembly before the air pressure is applied to the vent "TEE" opening, or damage to the bladder may result.

6. Release the air supply, and submerge the tank in water or apply soap solution to the outside of the tank.
7. Reapply 7 to 10 kPa (1 to 1.5 psi) air pressure to the fuel return tube on the fuel level meter assembly. With a second source, apply 7 to 10 kPa (1 to 1.5 psi) air pressure to the hose connected to the "TEE" fitting.
- Air bubbles indicate a leak in the metal tank. Replace the fuel tank if it is leaking.
CAUTION: Air pressure must be released from the hose connected to the "TEE" fitting before releasing pressure from the fuel return tube on the fuel level meter assembly, or damage to the bladder may result.
8. Release air pressure from the hose connected to the "TEE" fitting.
9. Release air pressure from the fuel return tube on the fuel level meter assembly.