The new gas caps have a valve in them that is supposed to open to allow fresh air into the tank to replace the fuel that's being sucked out by the fuel pump. Like most garbage new parts, they don't work like they should or fail soon after installation.
If yours is like the one below, disassemble it and remove the valve and spring.
Unfold those two metal tabs that hold the metal washer and all the plastic stuff in place. Remove the washer, plastic vent, and valve assembly. Under that vent with the five holes is a rubber valve and spring.
Throw out the valve and spring and reassemble the rest of the parts in the order you removed them. Fold those metal ears back into place and install the cap on your truck.
Last edited by Otto Skorzeny; 10/31/20266:42 PM.
1950 Chevrolet 3100 (Ol' Roy)
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
