MF 135 up/down distance of steering shaft to enable Pwr Str

Have a 1970's, MF135, Perkins, with factory power steering. Steering went out several years back and finally got around to fixing it. Took Pwr Str pump and Steering Gear Assembly to MF Dealer for rebuild. Pump was rebuilt and tested. Steering gear assembly: had Steering cylinder with all of it's associated parts replaced and Steering Control valve replaced. Tractor is at MF dealer and they are unable to get power steering to work. After many hours of research and calls over the US, still unable to get P-S to function. Pump pressure is 1200 psi and flow is within spec's. Inspected steering control valve to measure distance spool would have to move to allow full porting of oil to steering cylinder (+/- 0.25"). And the spool would have to move at least +/- 0.08" to start porting oil into the steering cylinder. I took some crude measurements of the steering shaft up/down movement: up 0.070" and down 0.045". So, steering shaft is not moving up/down adequate distance to move spool in steering control valve to port oil into steering cylinder. What determines the up/down movement of the steering shaft??? Anyone have a hydraulic schematic for Power Steering??? Tractor has been down for 4 months and got to get it going. Sure would appreciate someone sharing their knowledge and experience......

My I&T manual says tighten the lock nut to about 30 foot pounds, then back off 1/4 turn to give the right end play. Stake the nut to the shaft to hold it there. I"ve not done that and I trust I&T not much. I'd rather have the factory shop manual.

Gerald J.

Hello,
The type of PAS that you have is the one fitted to just about all UK 135s with PAS. I think that you are loosing movement on the spool valve somewhere. You are not showing an e-mail address. If you send me an e-mail I'll send the pages with the adjustment procedure. The images on YT may not be large enough to see clearly in this instance. You can make direct images larger.
DavidP

Hi guys,
Interesting! The UK gen MF 135 manual gives a figure of 10 lb.ft then back off one flat.
DavidP

Gerald, The IT manual information matches the MF 135 shop manual.

I have an MF40 with the same steering set up - as you have discovered the spool valve does not have to move very much to activate the power assistance. Check for wear in the pins/holes of the spool valve linkage. I tightened up these clearances with slightly oversize pins and fixed mine. Another thing you can do is while holding pressure on steering wheel try levering spool valve linkage in the correct direction - if the problem is lack of movement at the spool the power assistance will kick in when the spool travels far enough. Adjust the linkage to get equal travel in both directions. Good luck,
Bill

If you have a MF40 industrial you have hydrostatic powersteering. The type found on the 135 is power assist They are different setups and BOTH are pricey to repair

Hi Gary - not sure if all MF40 industrials are the same but I have a workshop manual for an MF135 and it shows the same power steering as is fitted to my MF40 - spool valve on the steering column that actuates two rams each side of the front axle beam that work via bell cranks onto the axle spindles. I am in Australia so this may have something to do with differences? Cheers,
Bill

Definitely there are steering differences. My US MF-135 has the power steering cylinder on the front side of the steering gear box. A single cylinder pushes and pulls a rack over the top gear. While the UK (which is probably where yours is from) use the cylinders up front. Some used cylinders alongside the drag links. Likely the control valves are different. I know from my US parts book that there were several different pumps and reservoirs used besides the differences between the Perkins and Continental engine mountings.

Gerald J.

Well! it sounds like there were 2 MF 40 Industrials UK & NA versions.
The MF135 Orchard special has hydraulic cylinders (2) mounted on the solid non adjustable front axle and uses the same control valve as the other NA built style of power assist steering. I believe the UK & NA control valves are different. UK also switched to the straight front axle(adjustable) with no radius rods The UK models are more desireable as a loader tractor because of their better designed front axle & power steering setup

My setup is the same as your's. Anyone have a fix for this lump of iron???

(quoted from post at 17:15:45 12/23/09)
My setup is the same as your's. Anyone have a fix for this lump of iron???

Click to expand...

This response is in reference to Gerald's US MF135.........