MF 35 Hydraulics

[Danny2466]

I have a 1965 Massey Ferguson 35 tractor gas with a front bucket and rear 3 point. The front hydraulics work fine no leak down, but the back 3 point leaks slowly down when I push on the clutch. Please could someone give me some ideas on what to check or if you know some trouble shooting things I can try to find out what is going on and possibly come up with a fix for this. I really like the tractor and want to keep it, but the back hydraulics to be able to work.

Thanks
Danny2466

 

[Dieseltech]

Does the tractor have the single stage or dual stage clutch? If single then the three point WILL lower as the driveline stops completely on the single clutch models. On dual clutch three point will also lower whenever the clutch pedal is all the way down, which stops the hydraulic pump/PTO driveline. If the dual clutch is adjusted/working correctly then the hydraulic/PTO should NOT stop when only the first clutch stage is being used for transmission shifting.

 

[Jack in NB]

Hello Danny -

That leakdown is one of the few weaknesses in that generation of masseys. We operated a bunch, and over the years through rebuilds reduced it on some. I never got rid of it completely, and they kept on lifting and working anyway. As DT says, the two stage clutch keeps it from settling in the half-way position.

I had to learn to lower any load before shutdown, because I had a few surprises with a load or implement coming up unexpectedly on the next start.

 

[chuckinnc]

I have 64 a gasser with multipower, everything works great except for the lift leaking down with the clutch in, just like yours, I just live with it because it seems to be a common problem with mf35 in these years. I add limiter chains that hook to top link
pin, if I going to be using it for days at a time.

 

[ptfarmer]

The piston ring type seal always leaks down, if you ever have to take the lift cover off go to the single Teflon seal piston (get a new lift cylinder with it). The new single seal is worlds better than the old style 3 piston ring seal.

 

[JBKINWA]

Best answer is to mill lower piston ring groove to accept a .250 O-ring. That was Massey's fix but was never put into production. It was in an old service bulletin. You would have the 2 cast upper rings and the O-ring. They didn't use the Teflon wear ring at that time but I don't see why combining the new style ring with that fix would not work. I have worked at factory level maintenance before and have run into times they just wanted to sell parts instead of fixing it. Who knows.

 

[Tony in Mass.]

Dieseltech's explanation is the easiest, learn how to 'feel' the 2 stage clutch.
JBK has the long term fix, long job to do it, but like Fords, an 'o' ring in the piston will stop the leak down.... but... gotta remember- Harry Ferguson designed it to do just that- as a safety feature, if the engine was shut off and an implement left raised, the hitch would slowly, safely, lower, rather than the lever get accidentally moved later, and -whatever back there drops unexpectedly... and fast.

 

[JBKINWA]

Your right when you say longer and more expensive to do that way. When I fixed mine recently I went with the new style. Mill time was expensive when I needed a lathe that would accept 3 3/8" stock. I had already lost too much time getting the repair done and needed the machine. But if you decide to do that you might also consider shortening the piston skirt. Based on the wear pattern in the old cylinder it protrudes beyond the cylinder bore at max extension. The side play would increase wear and loss of sealing. With iron rings you will always have leakage through the ring gaps, that's engineered in for a couple of reasons. My old piston was still serviceable and I will get it milled and on the shelf for the next time.

 

[ptfarmer]

I just buy the entire 3 3/8 lift cylinder with the Teflon seal already installed on the piston for $138 shipped. On another note hearing about the expensive cost of machine time, I must not be charging enough for it. My lathe can only swing up to 15" diameter x 60" between centers, wish it could swing up to 20" diameter.