Lift Arms Drop When Clutch Is Depressed, Massey Ferguson 35
We have a customer who has a problem with the hydraulics on his Massey Ferguson 35 tractor. Joe has sent in a picture of his tractor, which looks absolutely superb.
The lift arms are dropping whenever he depresses the clutch pedal, here is what he says…
I enjoyed the MF 35 Hydraulics DVD. It is professionaly done and very informative. I’m wondering if you can help me diagnose a symptom that wasn’t discussed in the trouble shooting portion of the video.
The hydraulics on my MF 35 have been working well ever since I’ve owned it (about four years). In the past, I could leave the arms in the raised position and for several days they would stay raised with very little down ward drift (I didn’t make a habit of doing this). However, this spring when I first attempted to use the tractor (after it sat for three or four months), the hydraulics starting acting up. Specifically, the lift arms would rise as they should, but as soon as I depressed the clutch (to put the tractor in gear), the arms drop (very quickly). As soon as the tractor begins to move, they rise and assume the proper position. Any idea where I should begin looking in the hydraulic system??? Is there a check valve in the hydraulic circuit that prevents the hydraulic fluid from flowing out of the lift cylinder once the clutch is depressed? If not, what prevents the the hydraulic fluid from flowing out of the lift cylinder once the clutch is depressed–the control valve? I have a single stage clutch.
If the tractor has been stood for a few months and the symptoms have developed all at once then it is most likely just the o’rings on the stand pipe. Just remove the cap (front right hand side of hydraulic top cover, under seat) and pull the stand pipe out. Replace the 3 o’rings (1 under cap and 2 on stand pipe) and also preferably the back-up washers (nylon spirals).
It is obviusly a leak on the system somewhere, but the reason I suspect the o’rings is because they do not sit in oil and so may have dried out.
I think that will solve your problem.
Vintage Tractor Engineer