Highwayman

I can't get the locking gas cap off my 56. This thing is old and not like most caps I see now days. The newer caps just spin when locked and turning the key engages the bottom section and you turn the cap off. This cap does not spin freely when locked.


The cap has two fingers inside the filler neck that retract when the key is turned. The lock cylinder turns fine with the key so I don't see how drilling the cylinder to use a screwdriver would help but I don't know. The fingers in the cap simply won't release. I suspect the mechanism internal to the cap that retracts the fingers has given up.


So I thought I'd post a picture of the cap and see if anyone here has any experience with one of these.

Rickman48

Try squirting a lot of WD-40 in the cylinder - the locksmiths best friend!!
Fill it a few times - should work like new!!

Highwayman

That was the first thing I tried. That and plunging the key in and out a few times. The cylinder seems to turn fine with the key.

But you said to do it a few times. I'll try to repeat a few times in case it just isn't getting the last few thousands of an inch.

rocketraider

IIRC those caps have a substantial rubber seal. Try pushing the cap down on the filler neck in case the seal is putting enough tension on the fingers that they can't retract.

Texascarnut

Either that or the rubber has become sufficiently stuck to the filler neck it needs to be broken loose. If that should be the case pushing down on the cap may break that seal.

Now here is something to think about. If it is an old, old cap it may well be a victim of Ethanol fumes softening the rubber and causing it to fuse to the filler neck. Don't know if Stant or other makers of locking caps have considered this as a potential problem and changed the type of rubber they use, but if the cap loosens I'd be buying a new one in hopes of preventing future occurrences.

Highwayman

Thanks for the suggestions and it is an old, old cap. Probably from the fifties or sixties. I already have a new, standard cap ready to go back on.

The rubber isn't stuck. I can turn the cap about an eighth of a turn and rattle it enough to get a feel for which direction the two retaining claws are pointing. This is an old vented cap that wasn't intended to seal tightly.

The key works fine in the tumblers and the lock cylinder rotates, it just won't release the retaining claws. I'm going to get out this afternoon and try flushing the lock some more like Rickman suggested on the chance there's still some grit that is keeping the lock cylinder from turning far enough. It's the least destructive thing I've got going at the moment.

My gut is telling me the internals are just flat worn out and I'll end up cutting it off somehow.

Texascarnut

If the key is turning easily the locking tangs should be retracting implying the sticking is something else. On the other hand the something else could be the tumbler is turning but the releasing mechanism for the locking tangs is just flat broken or distorted to the extent the tangs remain engaged.

I think I'd try using channel locks large enough to grab that cap and give it a serious twist. Last thing you want to try is cutting anything simply because it just isn't safe to do so unless you can detach the filler neck from the tank. If that guy is like my '56 Cadillac there should be a rubber transition connection between the tank and the filler neck.

Highwayman

Thanks for the input guys! I used more WD-40, some big channel locks and the encouragement went a long way. There's a brand new shiny chrome, non-locking Stant topping off the filler neck now.


Turning the key with one hand and big channel locks with the other I managed to pop one of the claws loose. The old claws just flat didn't want to turn loose. Then I literally pulled up the loose side and peeled the other side out. The old cap has a lot of wear and was probably just worn out and didn't want to budge. I can relate.


I know everyone like pictures so I took a couple. Not the best, but I tried.

Texascarnut

Nothin' like success!