I've been rebuilding a 1972 MF 135 UK with my brother and while we're mechanically inclined, this is our first tractor. We've muddled through power steering, brakes, ring & pinion, control spring overhaul, etc. but we're having problems with hydraulics now. The oil in the old tractor was bad (milky) so we replaced that along with the filter. We also replaced lift piston rings. The linkage is our downfall. When we got the tractor a while back, the Position Control wouldn't work at all but we could move the lift arms with Draft Control. We took the lift cover off to get at the filter and to change the bushings in the lift arms; and to clean it all up, including partial disassembly of the quadrant. We have none of the special tools to set-up the lift cover so we put it back on hoping for the best. I did notice before installing that moving the Position Control lever did nothing. On the first re-install we bent the position linkage. Reading some posts, we fixed the that problem (roller had dropped off the end of the cam and bent the linkage mechanism under pressure). We put the lift cover back on and the position control works great now except..... the lift arms are pulsing in time with the pump as the arms are being raised and when holding a position. No pulsing when the arms are being lowered which would make sense since there's no pressure.
We're just about to remove the lift cover again to see what's up, so any advice on what to chase would be great.
BTW, now that the position control is working, the draft control doesn't seem to do anything. As soon as you move the lever, it sends the control lever to discharge position (and I mean all the way forward). There is no in between at all. Just goes forward and stays there.
Thanks for looking into my dilemma.
We're just about to remove the lift cover again to see what's up, so any advice on what to chase would be great.
BTW, now that the position control is working, the draft control doesn't seem to do anything. As soon as you move the lever, it sends the control lever to discharge position (and I mean all the way forward). There is no in between at all. Just goes forward and stays there.
Thanks for looking into my dilemma.