gas tank sending unit o ring

[Mel S.]

I installed a new O ring in my gas tank for my sending unit for my gas gauge in my 66 conv. All was well for about 3 months. Then it started to "leak" gas. I took it out, cleaned all surfaces, let dry and applied a small amount of black oil resistant silicone on all surfaces. Reinstalled all and good to go. Now, about a month later, it is leaking again. I purchased a new O ring but wanted some input before I "tried" another install
Thanks
Mel

[Harry S.]

Re: gas tank sending unit o ring

Mel, the reproduction O-rings are not as thick as the originals, so they start to leak quickly. Originals are available often on eBay.

[Dan B.]

Re: gas tank sending unit o ring

Also, the O ring should be soaked in oil prior to install which will cause it to swell slightly and fit tighter. No other sealer is needed.

[Mel S.]

Re: gas tank sending unit o ring

Thank you very much
Mel

[Larry M.]

Re: gas tank sending unit o ring

The GM Part # for the o-ring is #3825206. None (NOS) on Ebay currently. Be advised that GM has reissued this o-ring gasket, but that newer part is currently back ordered. The GM re-issue may be the ticket for getting a good one.....if you cannot find NOS. NOS have a "JR". logo on the o-ring tab.

Also consider installing a new GM locking ring for the gasket. Part # 3774937. These are readily available on Ebay.

Larry

[Tim T.]

Re: gas tank sending unit o ring

Dr Rebuild has NOS ones but I believe he is still closed.
Tim

[Richard G.]

Re: gas tank sending unit o ring

I had to use the original lock ring on my reproduction tank. I couldn't tell the difference visually.
The original was much harder to turn and lock in place.
Might give that a try if it's an option.
Rick

[Joe L.]

Re: gas tank sending unit o ring

The GM Part # for the o-ring is #3825206. None (NOS) on Ebay currently. Be advised that GM has reissued this o-ring gasket, but that newer part is currently back ordered. The GM re-issue may be the ticket for getting a good one.....if you cannot find NOS. NOS have a "JR". logo on the o-ring tab.

Also consider installing a new GM locking ring for the gasket. Part # 3774937. These are readily available on Ebay.

Larry

Larry------


I'm not surprised the lock ring is readily available on eBay as they're still available from GM.

[Frank D.]

Re: gas tank sending unit o ring

Dr Rebuild has NOS ones but I believe he is still closed.
Tim

I believe that to be the case, but Lord forbid that I say so.....
There is a significant thinckness difference between the repro and original/NOS O rings as shown.

[Bob W.]

Re: gas tank sending unit o ring

Frank, This is bad when they cant repo a rubber o ring correct.

Bob

[Frank D.]

Re: gas tank sending unit o ring

Frank, This is bad when they cant repo a rubber o ring correct.

Bob

Look - there are a ton of parts like that unfortunately.....rear leaf spring rubber cushions, a simple glove box light socket, etc..
You would think with laser scanning, CAD/CAM and 3D printing the reproduced items would be as good or better than the original stuff.
[/rant]

[Bob W.]

Re: gas tank sending unit o ring

Frank, Maybe if the vendors would stop buying and selling this crap things would change. But I guess it all comes down to $$$$.

Bob

[Mel S.]

Re: gas tank sending unit o ring

Thanks again to all for the help
Mel