Ford 800 unload valve problems

JRA0015 · Dec 23, 2017

I have a 1955 Ford 800 that was my grandfather's. Me and my father have been trying to get the tractor back running. After some work the tractor runs and drives fine, however the lift had multiple problems. I have replaced the rings in the lift piston and check to make sure they aren't leaking. The pump has enough pressure to lift implements fine and I have replaced the safety valve on the accessory plate. However, the lift was still drifting down and not going all the way to the top with the control arm. I pulled the unload valve out to replace the o-ring and check to see if it was stuck. My unload valve had a steel o-ring instead of a rubber. The man at the new Holland shop told me I could replace it with a rubber ring and sold me the correct one supposedly. I can not seem to get the rubber o- ring to go inside the bushing. The shop manual says to lub it and it will simply slide in but I can't push mine in. When I try to force it then it shaves the o-ring off and you can hardly move the valve. Do I need a metal o-ring or a different rubber one? If I have the right part how do get the rubber o-ring and valve into the bushing?

Steve@Advance · Dec 23, 2017

Not familiar with the exact part you are working on, but sounds like you did not get the right size oring.

Others may have more model specific experience, but was there a problem with the steel ring? Does replacing
it with an oring offer an advantage?

If steel works, I would leave it steel.

If an oring is an improvement, try to find the correct size.

There are also different durometers (hardness) of orings. When making a change in something like this, best
be sure to use the proper oring. Might call the parts man that sold it to you, tell him the problem, there
may be other variations.

Bob · Dec 23, 2017

NOT familiar with what exactly you are dealing with, and if there was a changeover over the years.

I've posted a link to the parts catalog on the FIAT site, perhaps the parts breakdowns and part numbers may help?

Also, the Ford GURUS hang out at the Ford Forum down lower on the page. I suggest asking the question down there, as well.
800 parts catalog

JRA0015 · Dec 23, 2017

Thanks for the help. The steel o ring was badly worn and from what I found online though rubber one does work better. The parts list was a big help as it does show a rubber and a steel o ring. I will repost this on the Ford forum and see if anyone knows there as well.

Ford 800 unload valve problems

JRA0015

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Steve@Advance

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Bob

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JRA0015

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