The Stovebolt Site Forums The Shop Area General Truck Talk Fuel tank question

I replaced my old nonworking sending unit on my 51 with one that came with a set of gauges I got from a vendor and everything works great but I've had problems with the sending unit leaking from the mounting screws not from the gasket under the sending unit but from the screws ? I've tightened them and it's ok for a few days but then they start leaking again. The screws all have small o rings on them and for whatever reason I can't get them to seal, can anyone think of anything I can do to stop this ?

Hi, Clown. Two things come to mind, but not sure if either would work. Guess you'll have to try 'em and let us know. lol

There is a liquid thread sealant very similar to thread tape, but won't dissolve into the tank. A little bit of silicone might also work. Hope this helps.

Silicone will not stand up to gas.
You may want to try some Permatex #2 on the threads. It will stand up to gas.

Thanks I'll give it a try

Ditto on the Permatex. The stuff I used is called "High Tack Gasket Sealant". It had the no. 98H on the label, and also "item # 80062".
It seals the threads on the screws, and also never dries completely out, in case you ever need to remove them again. I used it on my F-350 and sealed the entire gasket with it.

Are you using a vented gas cap? I had this same problem when I bought a new vented cap, it held a couple of pounds of pressure, before the vent would open. I drilled a small hole in the vent, no more trouble.