MF135 hydraulic control lever stiff

MFIHCAT · Jun 28, 2014

I would not order any parts til after disassembly. There are a few orings in the quadrant assy. The master control spring is adjusted by first having no end play on the spring itself. It is removed to adjust that. Then it is adjusted with the large round retaining nut that also holds the boot in place to no end play. If the retaining nut is too loose or too tight you will have end play. There is a set screw thru the lift cover housing that keeps nut in place. Adjustment is made with draft lever down (if I remember right). There is a rod inside control spring section that can give you the wrong adjustment if in wrong place. With spring out you can see the rod, it should move in and out a little if the levers are working properly. But in this case you probably will have issues with that while still on tractor. When you have cover off and upside down you can see how the linkage works. Get the control spring nut broke loose while still on tractor, then you can take it out while its upside down. You will have a little more room that way. The MF kit does have a bent wrench that comes in handy for breaking it loose. Sometimes the nut is a little stuck after 50 years. But some penetrating oil should take care of that. I have before had to cut some out with torch, but thats worse case. Check condition of cylinder wall, should not be scored. There is a seal on the piston. There is also a small oring between cyl and lift cover. That one used to always stay there til the one time I put one back together and it leaked there. That one is more disassembly to get to, but worth it. Does this model have press. control? Do not use use silicone to mount lift cover back on. Use a gasket or flange sealer like Locktite 515 or 518.

bryanp66 · Jun 28, 2014

I am not sure if it has pressure control. How can you tell? Are the quadrants different?

Shenandoah · Jun 28, 2014

bryanp66 said:
If there is any sludge in the case after it is drained what is the best way to clean it out? Flush it with diesel?

They'll be sludge in the case, you can bank on it.

When I cleaned out my MF 135 I reached in through the PTO lever cover hole and scooped out what I could with some rags. There was a lot of goop that won't wash out with diesel unless agitated. You can feel around inside and target the areas where the case reinforcement ribs create nooks for the goop, like where the case splits. A shop vac with a small inverted funnel shaped hose tip may help as well if you can rig one up.

After I cleaned the goop out of my case, at least everything I could reach, which was substantial, I put diesel in a Hudson sprayer and hosed the inside of the case letting it drip out into a catch tub overnight. I sprayed through the fill hole as well as the PTO lever cover hole. Then I went back in with a few more rags just to see if any hard particles fell into the nooks and crannies after the spray wash. It's like panning for gold, those heavy elements don't flush out by themselves.

MFIHCAT · Jun 29, 2014

It should say on the position. Agcopartsbook.com shows what the difference is visually. Just login as guest. With press control you might not be able to remove standpipe thru the top, just remove the small standpipe cover before removing lift cover.

bryanp66 · Jun 29, 2014

I am almost certain that it doesn't have pressure control. When I bought the tractor, it had aftermarket hydraulic controls on the lift cover. It made it very hard to get on and off the tractor, so I replaced it with a factory standpipe cover. I could move the standpipe, so I am thinking it doesn't have it. The decals on the quadrant are almost worn off. I use the AGCO parts as a reference for part numbers to cross to aftermarket. Great resource! I'm glad you mentioned the lift cylinder because I planned to give it a good look while it is apart. Even if the cylinder isn't scored, would it be a good idea to replace the piston and rings anyway? My tractor is a '72 with 2400 hours on it. I would like to take care of everything that might be marginal while it is apart. Like you said, no use painting a tractor that isn't right.

MFIHCAT · Jun 30, 2014

It would not hurt at all to replace piston rings, but if you need piston you more than likely need the cyl also. Did it have the TS300 selector valve mounted on it. Those did not work all that well anyway. You are only getting about 3gpm out of the 3pt pump anyway, not enough to run aux hyd, unless you have time to sit and watch the cylinders crawl in and out. Some models also had a two or three spool control valve mounted on lift cover. There were a lot of different options on the MF135. Dont forget new orings/backup rings on standpipe and standpipe plate. Orings are cheap, usually. The service manual will show you how master control spring comes apart. It wont fly apart, but there is a little roll pin that needs to be removed.

redman135 · Jun 30, 2014

Hello bryanp66, before you start stripping things down, have a close look at the position control lever, it will have a small bolt with a spring and flat washer (friction to stop lever vibrating up or down on its own ) on it running in a slot on the quadrant. Compare this with the draft control lever friction spring. You will see a small flat washer against the slot. It wears out on the position control lever and the spring can get into the slot and "wedge" making for a stiff lever.
On my 135 I replaced the worn out washer and end of problem. Hopefully this fixes your problem.

bryanp66 · Jun 30, 2014

Thanks for throwing that out there Redman. I took a look at it, but that's not the problem. If I could only be that lucky

redman135 said:
Hello bryanp66, before you start stripping things down, have a close look at the position control lever, it will have a small bolt with a spring and flat washer (friction to stop lever vibrating up or down on its own ) on it running in a slot on the quadrant. Compare this with the draft control lever friction spring. You will see a small flat washer against the slot. It wears out on the position control lever and the spring can get into the slot and "wedge" making for a stiff lever.
On my 135 I replaced the worn out washer and end of problem. Hopefully this fixes your problem.

bryanp66 · Jun 30, 2014

MFIHCAT said:
It would not hurt at all to replace piston rings, but if you need piston you more than likely need the cyl also. Did it have the TS300 selector valve mounted on it. Those did not work all that well anyway. You are only getting about 3gpm out of the 3pt pump anyway, not enough to run aux hyd, unless you have time to sit and watch the cylinders crawl in and out. Some models also had a two or three spool control valve mounted on lift cover. There were a lot of different options on the MF135. Dont forget new orings/backup rings on standpipe and standpipe plate. Orings are cheap, usually. The service manual will show you how master control spring comes apart. It wont fly apart, but there is a little roll pin that needs to be removed.

I'm not sure of the model of the selector. It wasn't something I needed and it really got in the way of getting on and off. I have new o rings and backup rings on the list so far. Does it get a backup ring on the standpipe plate or just on the pump end of the standpipe? I can't remember offhand, but it looks like it gets an oring and backup ring on both ends on the agco parts page