Hydrostatic Power Steering problems
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=24251
Printed Date: 15 Nov 2024 at 8:55pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: Hydrostatic Power Steering problems
Posted By: Adam Stratton
Subject: Hydrostatic Power Steering problems
Date Posted: 17 Jan 2011 at 6:51pm
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This is off color (Massey 255), but I was hoping for some input. The tractor had been setting a long time before I got it. Previous owner said he thought a spindle was locked up, so had started taking the front end apart. When I jacked it up with the tie rods undone, I can move each wheel just fine. They are a little stiff, but moveable. When the tractor is not running, the steering wheel spins freely. When it is, it turns very hard especially to the right, even with nothing hooked up to the steering gear. I cleaned the screens on the powersteering pump intake, no difference. I thought it might have an air lock, so I opened the fittings on each end of the steering cylinder, and had oil coming out of each fitting without turning the wheel. That made me figure the oribal motor is shot. Does that make sense? I've had plenty of them cause trouble on AC tractors and had seals go out, or they would turn freely with the tractor running and not turn the wheels, but I havent had it go bad this way before. Before I spend the $350 or so a new one would be, anyone have any ideas? Thanks in advance.
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Replies:
Posted By: bobsouthernky
Date Posted: 17 Jan 2011 at 7:34pm
Adam I know what you are talking about. I have a 235 massey. It has the sorriest steering i have ever seen. They didn't make many so parts is hard to find. New is too expensive, and the thing isn't worth much if it was working fine. Good luck with your massey.
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Posted By: DrAllis
Date Posted: 17 Jan 2011 at 7:43pm
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Not being familiar with the MF hydraulic system(open center or closed center), why don't you put a plug at the end of each cylinder hose and then if the orbitrol is bad, I'd think it would still turn somewhat easily.....orbitrol good?? ..then the plugged lines would make it turn hard if at all. You also could be suffering from a pump delivery problem, which should allow turning of the wheel when lines are plugged. And by the way, in nearly 40 yrs of chasing AC's, I've NEVER replaced an orbitrol, just resealed them occasionally for leaks (usually up the steering column tube).
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Posted By: Adam Stratton
Date Posted: 17 Jan 2011 at 8:20pm
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I guess we have just had a bad string of luck with them. We have been able to send them off to get them rebuilt versus replacing them, but had one go bad on a 190XT that the top seal went out on, and had one go out on our 7580, and have had 2 go out on Steiger tractors. I plan to try the plug idea. Also, do you know what pressure the pump should be putting out? The oil is frothy also, if that should tell me something to look for. I thought if the orbital was sending oil to both ends of the cylinder at the same time, that was probably what my problem was, but maybe the seals in the cylinder are so shot the oil just flows through? Thanks for the help so far.
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Posted By: D-17_Dave
Date Posted: 17 Jan 2011 at 8:32pm
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I don't recall when but sometime after the orbital steering valves started being used they began using back pressure from the valve to help dampen the action of the steering cyl. Light back pressure keeps the "drift" from occuring also.
The valve is designed to act as a pump of some effect so if you loose oil flow (like a dead engine) you can turn the steering wheel and have limited steering until the oil gets pumped out of the valve. If the valve is that stiff under flow I'd say you likely have a bad valve. You'll need pressure gauges in both lines going to the cyl. and try tuirning the wheel. You should see the same pressure when neutraled, then quickly increase as you turn the wheel opening that side to flow. If you block the lines the pressure should jump up. If you tee into the lines going to the cyl. and the cyl. will move the gauge should come up to just what pressure it takes to move the assembly. When you get to full lock you should see relief valve setting pressure. If you see the static pressure on the guage in neutral and turn one direction, the pressure should never increase on the opposite direction gauge over what the static reading was until you direct oil flow to that side.
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Posted By: Joe(TX)
Date Posted: 18 Jan 2011 at 8:15pm
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Have you checked to make sure you have pressure and flow to the steering valve from the pump?
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Posted By: Steve M C/IL
Date Posted: 19 Jan 2011 at 12:18am
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Frothy oil sounds like sucking air through seals at pump.Never work right like that.
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Posted By: skipwelte
Date Posted: 19 Jan 2011 at 11:51am
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Check the steering cylinder Adam, it may be bypassing internally and can cause all sorts of steerring issues. HTH
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Posted By: Adam Stratton
Date Posted: 23 Jan 2011 at 8:16pm
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Thanks for the replies everyone! I unhooked the lines from the steering cylinder and hooked an air line to one end and did not have any noticeable air travel, so I put gauges on each hose going to it and started the tractor and the steering wheel was absolutely locked. I couldnt move it either direction and showed 0s on both gauges. So, I took the output line off the pump and had spotty flow with pressure I could nearly stop with my thumb. I took the pump apart checked and cleaned screens and the bypass/relief valve, put everything back together and had the same results. So, it looks like I am looking at rebuilding the power steering pump or getting a new one instead of working on the orbital. Thanks again guys!
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Posted By: Jim seIl
Date Posted: 23 Jan 2011 at 8:35pm
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Adam you can get a rebuild kit from massey and I think the last one I got was from I&T easy to install and you'll be surprised how easy it will steer
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