MF 50 No Power Steering to the Left

Craig L · Jul 12, 2020

Having issues turning to the left after rebuilding my power steering hydraulic cylinder and the control valve. After re-installing everything I have very little to no power steering to the left. I'm thinking that the adjustment on the control valve is out of adjustment even though I removed it and put it back on without changing anything. Is there a procedure on how to get this back to working again or is it just adjusting it till it works? Also, even after replacing all of the seals for both units, they still leak but very little. After disassembling both units I didn't see any thing wrong and I re-honed both before replacing the seals. Any suggestions on how to adjust this and where I can find either or both units? Thank you.

DavidP,South Wales · Jul 13, 2020

Hi Craig, I’m surprised no one has answered your question. You
would probably have been better to post it on the MF forum. The 50
model has the steering shaft in a pedestal operated by the ‘high level’
drag link. In common with most MF PAS systems it relies on a
controlled amount of play at the adjuster to work at it’s best. Have an
assistant rock the steering wheel back and forth. Follow the linkage
down from the steering box and check for play at every point. Play in
the mechanism will ultimately reduce the activating movement of the
spool valve. Places to look in particular are looseness of the main
vertical shaft in the pedestal and up and down movement in the
anchor point of the cylinder rod. Observe the amount of movement of
the spool valve. I suspect that you will find that the spool is not being
pushed in enough but is being pulled out sufficiently to give you pas
to the right. You can try and centralise the movement a little but if
there is wear present you are pretty much wasting your time.
Please let me know what you find.
DavidP, South Wales

Craig L · Jul 13, 2020

The PS worked just fine prior to me rebuilding the 2 units. After I reassembled on the tractor I did notice there was a lot of play in the pivot pin (the pin that goes between the upper portion of the gear box spindle and the lower portion, it has the large adjustment nut). I actually installed an old starter shim to make up for the wear in the pin and installed it before I started it up the first time after rebuilding the cylinders. When I noticed that I didn't have PS to the left I removed the shim but still had no PS to the left. I may need to have that pin re-machined or find a good used one. Still need to make adjustments to the spool to move it further inward. I believe even if I didn't mess with the shim I still would have this issue. This hasn't been disassembled or touched since the late 50's and when I put back together it may not be in the exact position as they came out. So roughly how much does that spool need to move in and out?

DavidP,South Wales · Jul 15, 2020

Minimum 1/16” to max around 1/8”.
DavidP

Craig L · Jul 24, 2020

David, thanks for replying. I did an inspection of the front end and noticed the 2 bushings in the pedestal assembly and the 3 bushing in the arm assembly needs to be replaced. I've spent quite a bit of time finding those bushing. I'll replace them and hopefully that'll take care of it and just get the shackle back to were it was originally. So after rebuilding both the spool valve cylinder assemblies, they still leak. I didn't replace one seal on the main cylinder because when I got the new seals that one just disintegrated in my hand. I've got new seal and plan on replace it. What I don't under stand is why the small spool cylinder leaks and it really looked good on the inside. I'll pull it back down and see if there's anything that may have gone wrong or maybe those seals were just were old. Any suggestions?
Thank you Craig

MF 50 No Power Steering to the Left

Craig L

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DavidP,South Wales

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Craig L

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DavidP,South Wales

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Craig L

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