I'm new here, so bear with me. I have some problems similar to a person back in 2009. I have a 1977 MF 1135 with a 122 (I think) Perkins Diesel. Which I have used and abused for about 15 years farming, logging, snow removal, and about anything else I can think of doing with it. About a year and a half ago, the steering started freezing up in real cold weather. I could relieve the pressure off the front tires with the bucket and it would steer again for awhile. Nothing I tried seemed to fix it. Then this early spring, late winter, the brakes stopped working. I could fill the brake cylinder up by hand and it would work awhile and then quit. I figured seals. About then, I started getting an intermittent squeal in the hydraulic pump. Thought it was belt for awhile. Bucket works fine. After reading the trouble shooting guide for the however many time I noticed the priority valve was what they had in common. I changed oil in the transmission, and cleaned the screen, and replaced the hydraulic filter. Then I pulled the priority valve off the tractor. I tried blowing air thru it. None went thru to the brakes, PTO, or something else, not sure what. There was a restriction to the steering, but the return line to the reservoir in the transmission was wide open. I cleaned it as best I could. There is a sort of nut in the center of the valve with holes in it allowing oil to go to the different places. It will probably take a special too to turn it. And one adjusting either needle valve, or ball valve. I took it to a shop where they have hydraulic specialist and he called me this morning. He couldn't get any info about rebuilding it either, but agreed with me it probably had pieces of something caught in it blocking a passage and restricting others. He also said it needed adjusted when it went back in the tractor. Some information on this valve, preferably with pictures, as I can be sort of dense,would be appreciated. This tractors been leaking hydraulics since I had it so it gets it's oil changed often, as it drains itself thru hoses and fittings. The screen in the transmission wasn't very bad, but the filter was pretty full of thick dark sludge. Thank you for your help.
Bill
Bill