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Fuel Cap Stuck?

dmat

Well Known Member
Advertiser
Hi All,

I just purchased a RV and the plane has been sitting for a couple of years. I was trying to open the fuel caps and I really needed to put some muscle into it when trying to get them off. It seemed as if there was a sticky film on the inside of the cap?

What could have caused this?

What can I use to clean it off without ruining the gaskets?

Thanks,
D
 
Fuel lube

Most likely it's fuel lube on the o-ring. You can clean it off with fuel. If you use fuel lube in the cold weather it is very hard to remove the caps also. I use a little vaseline to lube my.
 
There might be EZ Turn or Fuel Lube on them. It is commonly advised here to do so, but it is a bad idea, particularly when cold weather come around.

The technique for removing the caps matters also - lift the tab, push straight down on the tab, then lift up on the cap if you can get a fingernail under the edge.

They may be adjusted too tight also.

You could try spraying something like Tri-Flo into the nooks of the caps, it may fix the problem. I do this a couple times a year.

If not, you might want to dis-assemble them, and try to rub off as much of whatever glop is in there as you can. Perhaps get new O-rings (small one and large one). No common solvent will dissolve the stuff (if it is EZ or Fuel Lube), so wiping away is the only method.
 
Thanks Gents!

I will try that later tonight when I get to the airport.

D
 
BTW, the nut on the bottom of the cap is not there to adjust the fit.

I fuellube my O-rings every Condition Inspection.
 
The nut is a jam nut - the bottom piece is threaded. Loosen the nut, rotate the bottom piece as necessary, re-tighten the nut.
 
BTW, the nut on the bottom of the cap is not there to adjust the fit.

I fuellube my O-rings every Condition Inspection.

The nut is a jam nut - the bottom piece is threaded. Loosen the nut, rotate the bottom piece as necessary, re-tighten the nut.

Or maybe not.......

It all depends on the age vintage of the caps.

The earlier version of the caps did not have the lower plate of the cap threaded.
The adjustment was made by just turning the nut.
The older version cap also didn't have the white delrin plastic glide inserts for the o-ring to slide against, so that is an easy way to determine the version.
I think the were updated sometime in the early to mid 90's
 
It seemed as if there was a sticky film on the inside of the cap? What could have caused this?What can I use to clean it off without ruining the gaskets?

Fuel Lube, aka Easy Turn, as others have indicated. Avgas will NOT dissolve it. It's there to keep the o ring lubricated, so no reason to remove it unless it is all over the place and a nuisance to you.

Erich
 
Or maybe not.......

It all depends on the age vintage of the caps.

The earlier version of the caps did not have the lower plate of the cap threaded.
The adjustment was made by just turning the nut.
The older version cap also didn't have the white delrin plastic glide inserts for the o-ring to slide against, so that is an easy way to determine the version.
I think the were updated sometime in the early to mid 90's

Ha, yeah, I knew that but was just testing you Scott! ;)

Mine were bought in 1994 and have the Delrin cones and the thread adjustable bottom.
 
I seldom find that I have anything worthwhile to add to these threads but this one is the exception. Fuel Lube (EZ turn) can be cleaned up using denatured alcohol. Wipe off the excess with a paper towel and then follow up with a towel saturated with the alcohol. Works great.
 
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