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I have an mf 35 and just recently the lift will pick up and work for about 45 mi’s then it goes down and won’t work again until it cools off.
Any ideas on what the problem might be? Your help would be greatly appreciated.
Obviosusly it is some kind of leak or inefficiency in the system that is becoming apparent when the oil is warm and has become non-viscous and thin enough to pass through/by the worn part.
It could be one of several things – worn pistons/cylinders, worn valves, worn control valve, worn rings on the hydraulic ram, wear in the lift cylinder or a leak somewhere in the system.
So where to start looking?
Well the leak/wear must be considerable if the linkage won’t lift at all when the oil is warm. If you take the side cover off (right hand side of transmission housing under the seat) and run the tractor (DON’T PUT YOUR HANDS INSIDE WHILE THE TRACTOR IS RUNNING), put the position control lever to UP. Look inside for any obvious leaks – particularly the stand pipe or lift cylinder. If there is a leak then you will be able to see it (if the lift won’t raise at all). If there is no leak then I would remove the top cover (the large piece under the seat) and remove the pump. It is possible that there is problem with the relief valve (can be replaced through the side cover without removing the pump), but more likely it will be the control vavle which will need replacing , or the pump components, or the vavles (in that order I would suggest). The method for assessing these components is shown on our Hydraulics DVD.
A full repair kit isn’t too expensive if you don’t want to go through the process of replacing individual components, putting the whole thing back together and then finding that you have to start over again as you have replaced the wrong part!
One thing we have found over the years is that the aftermarket control valves (and relief valves) have rarely been manufactured to the required standard. The control valve is an extremely precision component as it needs to be both oil tight yet also facilitate movement along its washers. Therefore, a genuine Massey Ferguson control valve is always worth the little bit of extra money.
Hope that gives you some ideas.