Repairing a Leaking Zenith Fuel Valve

Anyone who has a 600-800 -900 series Ford has probably had problems with the fuel valve on the fuel tank. I know I've had mine off many times trying to correct the repeated leaks that develop.I'm now celebrating a year with no leaks. This is how I finally beat that damned contraption:

1.-Drill out the rivet being pointed at in the pic. It holds the valve in the housing. With the rivet removed the valve will screw out of the body.

2. - Replace the O-ring on the valve. If your valve is leaking, the O-ring will be worn down flat/flush with the valve.

3-Clean the rust out of your fuel tank and seal the tank if needed to prevent future rust. Even though there is a screen on the fuel valve, a very fine dirt/rust grit will pass through it and deposit an abrasive film in the valve, which causes fast wear to the O-ring.

4.-Use a small buff on a dremel tool and some buffing combound to smooth the inside of the housing where the O-Ring rides. The machining on this part is coarse and causes wear to the O-ring unless smoothed up.

5. Cut down a machine screw to replace the rivet, reassemble the valve and JB Weld the screw in place. The screw won't leak and is not all that hard to remove for a future rebuild.

Since redoing the valve and sealing the tank, my valve works very smooth and no more leaks. Used up a lot of good cuss words on that valve before I got it to behave.

I was cleaning out my jpeg folder and came across this picture, I know alot of the N-owners also have 100 series tractors and thought you might find this info useful.

Funny thing - I've never had a bit of trouble with the valve on my 8N. Must be a better design.

FWIW - Mark

The rivet shouldn't be exposed to any fuel as long as the O-ring does it's job. In this case, if the O-ring fails I'll have fuel leaking around the valve too, and it will be back to the drawing board! :-)

Lots of times they are damaged my someone opening them with too much force when the screw reaches it's outward limit. This will damage it every time. I have leared to open this valve no more than two complete revolutions.

One thing I might add about o-rings in general. You can extend the effective life of them (if they are not abused) by putting a very light coating of silicone grease on them. You don't leave any goop on the o-ring, you just make it shiny.

One of my hobbies is scuba diving and I shoot underwater video. As such, I've gotten pretty intimate with o-rings, because they are what keep salt water out of my camera housing and prevent the conversion of a very expensive video camera into a door stop. I'm religious about keeping the o-rings pliable to ensure they continue to seal well.

fwiw..... ..Ed
'52 8N475798

I also considered machining a second O-ring groove on the valve. I felt if one O-ring is good, two would be better. It also appeared that the space between the O-rings would hold some type of lubricant safe from fuel exposure. Never got that far with the fixes but it seemed like a good idea.

Scuba diver huh? Great hobby! I went through NAUI certification back in 1978, went diving for a couple years, but myself and dive buddies went in other directions and I eventually sold my gear. Regretted it, I assure you. Very enjoyable hobby.
Mark

Thanks for a great pic to further illustrate the topic. Much nicer than my ( "Let's push all the crap to one side of a greasy workbench and shoot a lousy photo")effort! LOL!

The T handle is grafted on to a newer "screw" valve if you look close. The valve on the right is the original one from 1955 and is a different design, unfortunately it was beyond repair. I took the T handle off of it and grafted it on the zenith as it made it easier to turn and looked more like the original that way