MF 165 Power Steering

Josh8906

Member
I have a MF 165 that I can't figure out what is going on with the power steering. I have replaced the power steering
pump twice. They only last about 8 months of good use. When I first install them the steering is real easy and then
after they get some wear on them it gets harder to turn in either direction. Any ideas on why this keeps happening?
 
Has the pressure line to the cylinder ever been brazed? Had a 175 years ago pump was worn out. Replaced it and right away could hear the relief valve blowing due to the pressure line being almost brazed shut. Replaced the line and rechecked the cylinder/control valve settings and it steered fine after that. Owner never said when or who brazed the line though..
 
Hello,
If you suspect that the pump might be faulty then a pressure test would be the first step. Connect a suitable gauge to the pressure line. At 1000 engine rpm and with the oil warm you should have a figure of 1500 - 1600 psi. Have you checked that the filter is clean? If you are having difficulty steering then the problem could well be in the actuating linkage. The type fitted to most North American MFs is slightly different to that fitted to UK and European tractors but the principle is the same. A spool valve mounted on top of the cylinder is actuated by initial movement of the steering wheel. This initial movement causes oil to flow to whichever side of the piston is required. Assistance is lost when too much initial movement is required and the steering operation becomes a combination of assisted and manual or all manual. Have an assistant work the steering wheel back and forth and observe the spool in both directions. Movement will be very small but should be very visible. If you have lost this movement in one or both directions check the linkage back to the steering wheel. There is likely to be play that is preventing the spool actuating. The most common area for play is between the vertical main shaft and its bushes in the axle casting. Wear other than the controlled adjustment to actuate the spool will reduce assistance. Check also the point at which the cylinder rod is attached to the axle casting. Up and down movement here will also cause reduced assistance.

DavidP, South Wales
 
OK I have checked the filter and it is clean. I thought about replacing the actuator linkage to see if that helped. The steering does have play in it but when the pump was put on it steered fine with the play. Would the play in the steering still make the pump go bad? I also noticed when I put the new pump on it would making a humming noise when turning left but done ok turning right. I adjusted the linkage to see if it would help but I could never get it to stop. Thanks for the help.
 
Can't see anything that would cause the pump to wear. make sure that the spool is in neutral at all times when not actually steering. If the adjustment is out it may be open slightly on one side.

DavidP
 

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