Ford compact 1910 Hydraulic problem

[RBinDevon]

Hi,
My 1986 Ford 1910, the 3pt hitch system lowers itself quite quickly when the engine is switched off. Full up to full down in about 1 1/2 to 2 mins even with the lever still in the full up position and the valve that controls the lowering speed fully closed.

When I had a load in the link box (engine running) the box lowered itself, then raised back to its up position. The movement on the back of the box was about 1 inch.

I guess that it is either the seal in the lift cylinder or a non return valve in the flow from the pump is letting oil out.

Does anyone know of a test to isolate where the problem lies rather than stripping down the complete system.

This is strange and it only started doing this after the transmission oil (also used from the hydraulic system) and filter were changed.

Normally I used Agi Castrol, but this time I used UTTO (universal tractor transmission oil, that stated it was for the combined transmission hydraulic type tractors).

Any pointers would be greatly welcomed.

I am worried that a complete failure might occur, have to put in about 100 posts with my hydraulic post banger and don't wanted to get stranded.

Thanks.

RB

 

[Kiwi Pete]

Without knowing what I'm talking about, I'd look at the lift cylinder first. The oil change may have stirred up something that's got under the seal and caused a leak, or it was leaking a small amount previously and the new different clean oil has made it more noticeable. We had a buggered seal in more than one tractor and it sounds like the same hop to me. Imagine you will just pull the top cover off- unsure whether that's under the seat or not- pop the piston out by manually raising the back links up and down, and replace the seal. Hasn't taken me more than an hour and I'm moderately handy with a spanner.
I should clarify: put the arms down before you open it up, a helper is handy to lift the arms up and down while you grab the piston and help it come out.
If that doesn't work then I'd slap the cover back on and pretend I hadn't been in there. Proper mechanics don't like you fixing stuff.

 

[RBinDevon]

Found the problem. The pressure release valve for the lift cylinder was not seating 100% don't know where the little bit of dirt came from as it is only feed by filtered oil from the pump. All working as it should.
I am a happy bunny.