860 fuel leak

[rbortnem]

I had replaced a tank valve several years ago because the shut off head was broken when I acquired the tractor. Recently I noticed a very slow leak from that area under the tank. I removed the hood and tank and took off the valve. The first thing I noticed was the skinny o-ring had swelled and wouldn't fit the groove in the valve (not the thickness of the o-ring - the ring size). I called the FNH dealer and had him send me a new o-ring. By the time it arrived I noticed the old one had dried out and shrunk back to normal size and looked identical to the new one. I also had an old o-ring from another ford shutoff valve that I had replaced on a different Ford tractor (had no problems with that one) that was much thicker than the replacement. I tried that with my leaker and it still leaks. It is so small a leak that you can't see where it comes from. I have the tank on saw horses with a plastic sheet under it and it might leak a tablespoon over night and the area on the tank surface surrounding the valve is wet. Would I be foolish to try a bead of gas resistant sealer in the area outside of the o-ring between the valve and tank? Any other ideas?

 

[Dean]

Do yourself a favor and use the correct CNH O ring and DO NOT over tighten the attachment bolts.

No sealant necessary.

Dean

 

[souNdguy]

i agree with dean... forget the sealer.. use the correct oring.

soundguy

 

[rbortnem]

Maybe my wordy description of the problem buried the fact that it's the "correct" FNH o-ring that was in there from the original valve replacement a few years ago. The replacement o-ring also cam from FNH and looks identical to the original. I just tried the larger one out of desperation. Since my original posting I've scanned the archives and have seen postings about internal leakage past the o-rings inside the valve. Could that be my problem? I wouldn't think the gas could "leak up" to wet the surface of the tank if the source of the leak was around the valve stem.

 

[souNdguy]

surface tension can make fluid 'leak' up.

ever seen a loop in a tv or phone cable that was running down a pole to some other location.. that's a rain loop. water can be forced UP the surface of the wire from the rain hitting the wire along it lower length.. the loop tends to defeat that a bit.

if it is a stem oring leaking, you can pry out the stop rivit, repalce the oring and then tap the rivit back in or tap for a small machine screw as a stop.. OR buy another valve.

soundguy

 

[Hobo,NC]

This may be yer problem hope not tho... I ended up doing the Por-15 thang to it and its been OK since... as far as the o-ring its a standard o-ring nuttin really special about it...



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