Jerry Feather

John, with your white part of the gas cap having the hole in the white part it is no longer sealing and the tank is vented to the atmosphere. The most common failure of the body of the gas cap is a broken red part, but I have seen and have one or two with a similar hole at the bottom of the white part. That ia a failure, but I think it might be one you could fix with a patch glued onto the bottom to cover it. I'm not sure what glue or material you might use for a patch.

As to the original problem you may have partially solved, I suspect there might be an unusual failure inside you cap with the pawl. The common failure of the pawl is for the back of it to break off which prevents it from being pulled back to disengage the teeth. However, I can envision, but have not seen before, a failure where the teeth have been worn away or broken off to the extent that they would not engage enough to allow you to unscrew the cap. I suspect that could happen where the user is prone to ratchet several clicks each time the cap in installed, rather than the recommended one or two clicks. Your statement about having it click one or two times when you are trying to unscrew it suggests this kind of failure since it should not click at all in the unscrew mode.

Alan

Jerry,
Other failure mechanisms for this could be the pawl getting gummed up in the channel or the pawl spring deteriorating/breaking. Given that the tumbler mechanism is exposed to tank gas I think that is a possible cause. The white section and overlapping enclosure of the red outer section is intended to protect the inner mechanism - however here there is a hole right through it!

There should be some spare white parts available since it is usually the red part that breaks...? the rest of the tumbler mechanism should be able to be cleaned/lubed fairly easily & transferred over easily, as usual replacing the red cover will be the most challenging part. (Hammer - Jerry can help you with that!).

I don't think attempting a repair to the white part is a good idea - here in Phoenix (and most places) that would fail a smog test even if only a visual gas cap test (as is usual for our caps). Should be easy & cheap to replace.

Alan

Wisconsin Joe

OP shows "central Florida".

No emissions testing there.

That doesnt' address the question of whether or not it's practical or smart to glue something to the inside of the cap, but at least it won't get the car "failed".

Lockrepair

upstate bob

OK, so now this thread has my attention, because my 79 has that ugly red cap with the keyhole in it too. I have all the original keys and maybe a couple extra but have never tried locking the gas cap.
Is a generic, non-locking cap available?

Jerry Feather

Nope. Never seen one.

Edit: On the other hand, most of them are non-locking because the ratcheting pawl inside is broken and they will no longer secure with the key; so they have become non-locking.

upstate bob

Locking it will not happen.. Fear of stolen gas is WAY down my list.

Alan

if you don't lock it - it's already a non locking cap!

Generic American caps don't fit on a 928 - but you can dispense with the red locking part and use the white part of the cap alone, the white part does all of the sealing and is a single piece with no moving parts - (its not too pretty on its own though...)

Alan

ReDesign by FEATHER

There is a lot of information in this thread about the 928 Gas Caps which are quite unique in the world. I am trying now to stimulate some interest in a program to solve the problem(s) with these caps and to develop that maybe even worldwide. See the other thread(s).