Farmall 460 overheating hydraulic oil

My 460 hydraulics work fine when the tractor is cold. After an hour of use my feet get hot and you can tell the hydraulic oil is getting too hot. My fast hitch then starts to drop and raise then drop and raise just a little bit. Then it gets harder and harder to lift implements with the hydraulics,like a wheel harrow. Again when I first start off everything works great and the hydraulics will lift anything, but then after an hour or so it just stops working and the foot plate gets really hot. Ideas? Anything worth trying before replacing the pump? Ive checked the valves and theres no rust in them, I am thinking maybe the adjustment for the fast hitch?

I would not think it was the pump, but a problem caused by lack of recirculation.

has to be oil running over the relief valve , as that will cause heat.

be certain the controls are centered when in the hold position. If it has single or double acting switches on the valve ends, make certain they are set all the way. Check the pilot pressure valve and tiny screen to assure it is clean. Jim

Sounds typical for a system staying on demand . Like others suggested, make sure your single and double action setting on the aux valves are lined up, no bent or broken roll pins. If that checks out you will need to take the four bolt cover off regulator, relief valve assembly. Note, heavy spring under cover for relief valve so take out two corner bolts and put longer ones in to avoid things flying apart. You will find a screwdriver head orfice with screen . Depending on how many times it has been repaired over the years, the original had a roll pin through the orfice holding a check ball in place. This check ball bounces back and forth and closes the orfice down. As this is a hardend seat they are difficult to re drill to proper size but can be done. It is only .031 so you need wire gauge drills to do so. Screen most likely is collapsed and plugged, you can cut off bottom to clean and wrap it back up again if it is not broken. Now for the fun part. Sometimes you have to make the hole in orfice slightly larger to compensate for the wear on the lands in the control valves, mostly the hitch valve is the problem. I usually go for about .040 to start with, as if you go too large your system will not pressure up when you use the valves. But first off, clean orfice, throw away the ball, and try that with original size. You will need a new gasket and also replace the o-ring on regulator piston and polish it up nicely.

On my 560D, if the fasthich height control levler is set too high, or low, on the quadrant, you can hear the pump strain. I then back it off until I no longer hear the pump strain. So maybe your linkage, like mine, is out of adjustment? Just a thought. Deadheading the pump constantly will definitely cause alot of heat.

I am going to check out the relief valve assembly today and hopefully Ill find something there. I first need to locate the relief valve assembly haha. I have the technical book so hopefully that will give me the name for it, I"m assuming its the valve assembly below the dash.... Also my fast hitch does not bottom out and strain but it does top out and strain but even when its not in that position it eventually starts heating up and dropping.

You could also have worn rings on the lift cylinder(by-passing) and the position control is fighting to maintain set position. Then the oil gets too hot to work correctly and lets the load drop.

I need to tear into my 504 3 point because it "hiccups" and gets worse as the oil warms up. Any internal leakage will cause heat. When I'm mowing with my 504 in the summer, my oil temp has gotten to 200 degrees. I know it is because the rings are leaking, cuasing heat.

I may be off base here, but it sounds good. 8)

CT

Hey I also have a 504 that does the same thing haha.
But that one isnt bad enough that I worry about it.
But let me know what you find because Im sure at
some point Ill be fixing that haha. Anyway I didnt
get to the valve today, hopefully tomorrow thanks
again for all the help everyone. I love this tractor
but it can really be a pain sometimes and this is no
exception.

Hey Pete23 did you say to throw away the ball? Are you saying its not going to make a difference? Sadly it rained here all day so I couldnt work on the tractor today, weather looks the same for tomorrow. I may just tarp it to get it done, but let me know about that ball so I know what to do with it. Thanks for everything!

Yup, throw away the ball. Just for clarity, it is the ball in the orfice screen I am talking about an is very small, like 1/8 inch. There is another larger ball farther down in the valve under the piston but you need that one. IH thought this little ball in orfice was needed when then layed that valve assembly on it's side where in the earlier tractors the valves stood up and down. It was just another pain in the drain. Just make sure the orficer hole is at least .031, it should be stamped that size on it.

Well I was able to open up the valve and cleaned it out. The screen was a little gunky but not too bad, but it could have been plugging up those small holes at the end of the screen. I also cleaned up the inside of the piston chamber as best that I could but I could not for the life of me get the part with the ball in it to come out. I made a small spanner wrench to unscrew the ball valve but I couldn’t get it to unscrew! I bent the tool which was hardened steel, but it didn’t budge. I did push on the ball and oil came out and I cleaned it all with carb cleaner and the ball seemed to be doing its job and holding even the thin carb cleaner behind it. It wasn’t rusty so I put it back together. As soon as it stops raining for more then 1 day I will be able to try it out in the field and see if its working right now. I also adjusted the draft control which was set wrong and causing the 2pt hitch to be pressurized when it was all the way up. But I know I wasn’t running it all the way up when the problem occurred. At least it’s cleaned up and adjusted right, Ill let you know if it keeps happening.