Stuck fuel cell cap

[yellomalibu]

I decided to play with the Chevelle today. Pulled the carb, unstuck the valves under the squirters and re-installed the carb.
Put the battery charger on, then decided to fill the gas tank with some pure 93 octane gasoline (no ethanol) available at a local mom and pop oil and gas company... except when I tried to remove the gas cap, it acts like it still has a mechanical bond holding it down.

I called my buddy at the parts store (a racer/ builder) and he said to spray it down with wd-40 and let it sit... which is what it's doing now.

Has this happened to any of you?
Any other tricks to get the cap off?

[IRONHEAD]

Re: Stuck fuel cell cap

when you get it off look at the rubber seal.. and dab a liittle chapstick on it..

[Bamfster]

Re: Stuck fuel cell cap

If it's a JAZ cell, they are notorious for the tabs on the inside of the cap becoming misaligned. The quick fix is to remove the cap and file the corners of the tabs somewhat round/angled so it releases easier. That's what I had to do to mine ...

[yellomalibu]

Re: Stuck fuel cell cap

I don't think it's the rubber seal, if feels like it's still being mechanically held on the front side; the rear side seems free.

I don't recall if it's a Jaz cell... I bought it through summit, so maybe. It is one of the plastic cells with foam inside and a red fancy looking twist lever cap.

I DO recall that it has been finicky in the past; I've had to jiggle it to get it to open. Hopefully the wd 40 will do the trick. When (if) I eventually get the cap to come off, I will inspect the tabs, round the corners, and give them a good shot of wd- 40..

Note to others: If your fuel cell cap is finicky, take action now so you don't end up with a cap that won't come off when you need it to.

[CTX-SLPR]

Re: Stuck fuel cell cap

Is it well vented? Has the cell pulled negative pressure and is sucking the cap closed?

[yellomalibu]

Re: Stuck fuel cell cap

Is it well vented? Has the cell pulled negative pressure and is sucking the cap closed?

Yes it is well vented, no it hasn't pulled negative pressure.

As I'm yanking on the cap with the pliers, you can see and hear it acting like a bellows... but the metal tabs seem to just not disengage.

[yellomalibu]

Re: Stuck fuel cell cap

After sitting overnight... still no change. fr#@%ggin cap!

[Bamfster]

Re: Stuck fuel cell cap

I had to used a flat blade screw driver to get mine off. The first time it didn't damage anything, but after about a dozen times prying it, it finally did damage the seal. I replaced the seal and cap and it worked like a charm for a few years until it did it again, that's when one of my buddies told me about the fix.

[yellomalibu]

Re: Stuck fuel cell cap

The screwdriver did the trick.

This is like my cap:



After getting it out, I filed down the metal parts of the tabs like you suggested, even put a bevel on the top side... still got stuck when I put it back in.
Took it to the bench grinder, removed quite a bit more material, then filed the bevel back onto it and rounded the corners... still got stuck.

Looked at the metal part of the fuel cell that keeps grabbing the cap; it's just stamped steel with sharp, non rounded, slightly inward pointing angles where the tabs go.
I grabbed my fire extinguisher, grabbed a screwdriver and a hammer, and commenced to "adjusting" the metal by tapping it outward.

It worked... and I didn't make a spark into the gas :P.

...filled the fuel cell with gas, fired up the Chevelle and let it run until it got up to 180, revved it up a few times.... ahhhhh. I feel better about life.

[horsewidower]

Re: Stuck fuel cell cap

Sometimes the simple fixes are the most satisfying.

[yellomalibu]

Re: Stuck fuel cell cap

After further thought and discussion with my bud at the parts store, we've come to the conclusion that having the pressure of the spring loaded cap clamped down on the stamped steel insert of the tank for long periods of time actually pulled the steel inward - making the opening smaller, hence not being able to remove the cap.
This is why buying the cheap Summit brand stuff isn't necessarily a good value.