Power steering issue on a 1970s Massey Ferguson

[Devin 420]

So me and my neighbor use a 1970s era Massey 31 industrial logging tractor it has a new power steering pump (gear drive off the front gears of the engine) new hoses and cylinder, it steers fine when you first fire it up and take off but once the engine and pump get warm you have to lift the nose up with the blade to steer either way. Any
One got an idea as to why it does this.

 

[Harry in Ky]

So it's a new steering pump. It wouldn't be the first time that a "new" replacement part didn't live up to expectations. What sort of warranty came with the purchase?

 

[Devin 420]

Its not a fancy machine but it works fine when it steers

So it's a new steering pump. It wouldn't be the first time that a "new" replacement part didn't live up to expectations. What sort of warranty came with the purchase?

Not sure would have to ask my neighbor

 

[Devin 420]

Its not a fancy machine but it works fine when it steers

Not sure would have to ask my neighbor

He said no warranty

 

[Harry in Ky]

I can see a few possibilities. How was the steering BEFORE the pump was replaced? Was it pretty much the same as now? Maybe the pump wasn't the problem. The steering mechanism on that tractor has multiple wear points that can affect steering performance. Most all of that is in front of the radiator. Has any of that been looked at lately?

 

[Devin 420]

Yah it was the same before so he replaced everything he could to no success

 

[Harry in Ky]

It's quite possible the old pump wasn't a large part of the problem to begin with. More likely it's mostly a wear and adjustment issue with the shafts, pins, bushings and related linkage int the steering mechanism. You can remove the grill, start the engine and do some "self tests" with the steering and see what moves, what doesn't, and get a rough idea what needs attention. When everything is working as it should, you can reach in, grab the ball joint on the end of the steering drag link, push/pull on that and steer the wheels full right to full left with one hand. Trying that would be my starting point. With engine off, you should be able to see the control valve spool move in and out by doing the same thing. I'm betting there's enough slop in all the moving parts right now that it's not doing that. Check it out and see.

Then again, it may also have some piston seal issues in the steering cylinder.

 

[USMC43]

i have never seen a MF31 but it’s new enough that it’s more than likely the orbital steering valve under the dash. It is what the steering wheel connects to and controls how the cylinder functions. That is a common symptom with them


It could also be water in the oil turning to steam when hot or pistol seals in the cylinder but you said you put a new one of those on.

 

[Devin 420]

Thank yall for the help Im gonna be back out to help him monday so I can fiddle with it then and report back with what I find and see whats wrong from there.

 

[Devin 420]

i have never seen a MF31 but it’s new enough that it’s more than likely the orbital steering valve under the dash. It is what the steering wheel connects to and controls how the cylinder functions. That is a common symptom with them


It could also be water in the oil turning to steam when hot or pistol seals in the cylinder but you said you put a new one of those on.

The 31 industrial in my own opinion was a special mix breed type tractor, it shares parts with so many other models including the drivetrain but this one is different due to its logging setup that we think is either factory/dealership stuff or home brewed.