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Spinning gas cap (crap)

9.2K views 14 replies 6 participants last post by  Gubi  
#1 ·
The gas cap on my '87 spins and spins and spins, but never opens. Anyone have any ideas or suggestions?

I do not lock the cap, so that isn't it, but it acts exactly as if was locked... :(
 
#3 ·
I did try that - the key also spins and spins and spins, which doesn't help.... I wonder if maybe the lock cylinder broke loose in the cap and oriented itself in such a way that it's permanently disengaged?

I have no idea what the mechanism looks like...

Thanks for the quick reply, too...
 
#6 ·
Am I correct, then, when I say that the thread is held to the grip by the lock cylinder, and that when the lock cylinder fails the grip spins independently of the threads, thus preventing removal?

Strangely, when I tried to remove the cap last night the grip would not move then there was a crack/pop sound and the grip started spinning. Is it possible that the threads somehow seized in there and that I broke the lock cylinder? I'm very gentle with the thing - I never even tighten it down...

Just probing for other possible (possibly solvable) failures before I go breakin' stuff. :)
 
#7 ·
The key should not rotate more that 180°, sounds like the clip that holds the lock barrel in may have rusted away and the barrel has come slightly out.

The end of the barrel has a (offset crank) pin which moves a plastic bar which engages the splines in the section with the thread (see pics post 38 as before).

Two options:

See if you can press the lock barrel back in until it only turns 180° (you may have to rotate it as you press so that it's pin clears the plastic bar.

or

See if you can withdraw the barrel then engage the plastic pin with a screwdriver while undoing the gas cap.
 
#8 ·
That makes sense... the lock barrel spinning indefinitely seems like a problem. When it was quiet out last night I could hear a slight scraping sound as I tried spinning the key round and round... retrospectively, that probably wasn't the best approach. :)

If I can't re-engage that pin, I suppose it'll have be a slide hammer time... although maybe a locksmith would be able to somehow withdraw the cylinder more delicately.

I really don't care if the gas cap locks... It's rare (if ever) that I would leave the car in an area where I'd actually have to be concerned with someone siphoning gas or doing something malicious. I would just prefer to be not destructive, or have the car *look* like someone tried to siphon gas by breaking the cap... :)

Thanks all...
 
#11 ·
I found the answer to my problem:

Image


After understanding how things works, I popped the trunk and removed the entire filler neck from the car. When I flipped it over, I could clearly see what the problem was.... everything is all busted up in there. The lock spinning freely was unrelated to the cap spinning freely, but everything spinning freely meant nothing was spinning OFF.

I'm going to do a quick repair by epoxy-ing the outer cap (grip) to the inner body (the threaded bit) so at least I have a gas cap... I'll plug the keyhole with something to keep rain and dirt out. That should get it back to functional, and I'll find a real replacement whenever...

In case anyone ever wonders, these are the three plastic parts of the gas cap. This plus a lock cylinder make it work:

Image


This inner bit is the magic... and mine is sad and broken:

Image
 
#12 ·
Glad you got it off. Nothing some epoxy can't fix.

I'm curious - my lock cylinder spins freely as well with the key in. The lock works properly; that is, if I rotate the key 180 degrees and remove it, it's locked, and if I rotate it 180 degrees again it's unlocked. But if I leave the key in I can spin the lock cylinder in the cap as long as I like.

Sounds like the non-US version isn't the same and is restricted in cylinder rotation. Is that the case, or is mine partially busted?
 
#15 ·
I'm curious - my lock cylinder spins freely as well with the key in. The lock works properly; that is, if I rotate the key 180 degrees and remove it, it's locked, and if I rotate it 180 degrees again it's unlocked. But if I leave the key in I can spin the lock cylinder in the cap as long as I like.
Well, either I'm a liar or my brain damage is kicking in. I filled up today and the key rotation is in fact restricted to 180 degrees. Could've sworn it wasn't when I bought the car, but my memory must be going.

Sorry for the confusion.
 
#13 ·
I think the cylinder is supposed to be in a fixed position in the "grip" portion of the cap - possibly by a force fit? I don't think it's a problem, or a symptom of a problem. My issue was that the base of the grip was damaged, and the threaded "sleeve" was damaged.

I was pretty thrilled that I was able to remove the entire filler need without a lot of work so I could see the problem... it's a nice assembly!

I did notice that the little flapper in the neck was not firmly attached. I removed it. I don't think it is important, although I might fail smog without it. Meh... I've got two years to find another. :)