Ford 640 gas shut off valve leak

Jeeps

New User
Any ideas appreciated. Just tried the FormaGasket sealant from Permatex . Still getting a slow, slow drip. The valve is new. Thanks for reading and again, any ideas are appreciated. Thank you.
 
Where is the gas coming from? Is it the fuel line? Around the valve shaft? The mating surface between the tank and the valve? It does make a difference in how to address it.
 
I know from experience that those are a royal pain to get at, but the thing to do is take it off, clean both surfaces and make sure the o-ring is not damaged. Most silicone form-a-gasket products are gasoline soluble so that won't work. Get the bolts that hold it in place all started, then tighten them evenly and only as much as needed, Too tight can cause the gasket (o-ring) to squeeze out of place.
Like I said, it's a pain in the you-know-what. When I did mine, I sounded like a drunken pirate, but it held.
 
I appreciate your response.
Sounds like I could be guilty of over tightening the bolts and that o-ring, to me, could be made a little more dense so that it makes a better seal. I'll keep trying. Thank you for your time. I'll let you know how it goes.
 
Are you sure the leak isn't coming from the shut-off valve part and not from where it screws to the tank? I had to take mine apart and put a new o-ring in it to get it to stop leaking,if I remember right it was peened over and I used a dremel tool to get it out.
 
Use the proper (new) O ring, make certain that it is properly positioned and the mating surfaces are free of debris and do not overtighten. No goop.

It will leak if you do not use the proper O ring and/or the O ring grooves are not clean.

It will leak if the O ring is not properly positioned.

If you over tighten the bolts, you will damage the valve and/or tank and it will leak.

Dean
 
I suffered from this problem on my 641 for a long time. Finally, I got around to doing a major mechanical restoration on the machine. I found a leak in the tank where the bracket was welded to it. Decided not to repair old tank due to not wanting to weld on tank.
Threw the whole mess, tank valve and all in the dumpster and ordered a new tank from YT site. This tank had a bung on the driver's right side. Put in a bowl and valve, made a new fuel line and so long leaks!!
One less thing to worry about.
 
My 801 was leaking and I was ready to change the 0 rings, but I discovered if I didn't open it all the way, just 2 turns, it did not leak.
 
Thanks to all of you for your ideas. I'll try them out and let you know what happens. Thanks again.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top