Leakage of fuel and/or air past the drain and/or vent seal(s) can occur in the base of a Model 80 fuel filter. The two Model 80 assemblies involved are part numbers 14071933 and 14071064. The specific symptoms of this leakage are:
1. External fuel leakage from the vent or drain plugs.
2. A hard starting problem where the engine starts normally, then stalls, and is difficult to re-start.
A new seal (P/N 15529641) has been released to repair fuel and/or air leakage. The new seal has a slightly smaller outside diameter, enabling it to bottom in the bore and seal properly.
Seal replacement can be accomplished with the filter assembly removed from the vehicle as outlined in the following steps:
1. Remove the air vent plug located at the top of the filter base.
2. Loosen the drain plug on C/K model trucks and drain the fuel from the filter. On G and P models, open the remote drain valve to drain the filter.
3. Disconnect fuel hoses and wire connections from the filter assembly. Remove the assembly from the vehicle.
4. Unclip and remove the filter/separator element from the base.
5. A paper clip or short length of mechanic’s wire can be formed into a tool for seal removal. Using the tool,
remove the air vent and drain plug seal (if applicable) from the filter base.
6. Visually inspect the bore(s) for evidence of seal particles. If particles are present, compressed air can be blown
into the filter base outlet to remove small particles in the bore(s).
7. A short length of 1A ” bar stock or equivalent with square ends can be used to install the new seals in the base.
Apply a small amount of Synkut lubricant or equivalent, such as STP, to one end of the rod. Attach a new seal (P/N 15529641) to the rod’s end. Insert the seal into the air vent plug bore until it seats firmly in the bottom of the bore. Visually inspect the seal to ensure it is squarely bottomed. Install the air vent plug.
8. Repeat the above procedure to install a new seal in the drain plug bore, but do not install the drain plug.
9. Prior to installing the drain plug, measure the length of the drain plug bore boss. If the boss is V long, install the drain plug and tighten until it bottoms. If the boss is 1/8″ long, install plain washer (P/N 561890) on the drain plug and then thread the plug in until it bottoms. The drain plug washer prevents threading the drain plug in too far and damaging the seal.
10. Attach the element to the base.
11. The filter assembly can be pressure checked with air by plugging the fuel inlet, outlet, and drain outlet (if applicable). Using a maximum of 10 psi air pressure, open and close the air vent and drain plug (if equipped) several times to ensure the valve(s) are sealing.
12. Reinstall filter assembly on vehicle and attach all fuel hoses and wire connections.
13. Vent and prime the fuel system as outlined in the Service Manual or Owner’s and Driver’s Guide.
