Ford 841 - Hydraulic Pump Overheating

Hi everyone. Ill get right to it.
I have a Ford Powermaster 841 Diesel. The rear lift arms were not lifting all the way. I removed the lift cylinder assembly and performed the following adjustments: first the main control spring adjustment, then the constant draft (.395-.397), and then position control (.448-.450). I made sure to have the lift stop in place when adjusting the upper range of the control lever.
I Put it all back together and now, the rear lift arms lift to the top.
I noticed that when I tested the lift travel of the arms at idle that when the lift hits the top, a slight load can be heard being put on the engine. My first thought was, This thing is still trying to build more pressure, even after its in the full lift position.
Now Heres the problem. After about an hour of using the tractor, I noted fluid starting to leak. The rear lift arms were left in the full up position while I was working, as I was loading and hauling dirt with the bucket and not using the rear attachment. When i got off to inspect, It was hydraulic fluid coming from the hydraulic pump. The pump was so Hot that I couldnt touch it, and the gasket had blown out on the tail end of the pump, as well as the o ring now beginning to leak from the other end of the pump body. The system essentially is now overheating from what I suspect is either a result from something I did wrong with the adjustment, or a faulty pressure relief valve?
I dont know if the hydraulic pump was getting hot before I made the adjustments, but Im assuming not this hot if it was. Hopefully someone can help me out, because Im not certain.
Gasket kit is on the way, but I know it will blow again if I dont correct the problem. Thanks!

Hearing a load on the engine and hydraulics getting hot sounds like you have hydraulic oil dead heading somewhere in your system. What powers your front loader? Do you have a separate front pump, or does the tractor internal hydraulics power your loader?

The load on the engine is only noted once the rear lift arms reach full travel (to the top). As if the system is not releasing pressure once full lift is achieved, and its still trying to pump more pressure into the lift piston. It's definitely the rear lift cylinder and the load being put on the pump, which also explains why the heat in the pump. When the lever for the rear lift arms is put to the lower position, there's no extra engine load, only once the rear lift has reached the top. What valve is responsible for releasing system pressure once the rear has achieved full lift?

Sorry,for some reason I can't edit my last post to include:

The front loader is driven off of its own pump off of the front pulley. That system is working fine.
The rear is technically working too, but whatever the reason the fluid is not flowing freely after the lift arms are all the way up, is causing the restriction that is overheating the fluid. I'm just not sure if its a miss adjustment or a malfunctioning valve as to why its still trying to build pressure on the rear lift, after it has achieved full lift.

I am no expert on US Ford tractors but know a bit about their British cousins. In
the lifts there is something called a "knock-off pin", in the picture it is marked
with a red line. This catches the edge of the piston as it reaches the fully raised
position and moves the control valve and linkage into neutral. If you need to use,
say, constant pumping, you take the control lever beyond the top stop on the lever
quadrant which allows the lift to bypass this function.

It is possible to, incorrectly, adjust the internal linkage to allow this to happen
without going beyond the top quadrant stop.

(quoted from post at 13:11:06 12/09/20)
<img src="https://www.yesterdaystractors.com/cvphotos/cvphoto66332.jpg">

I am no expert on US Ford tractors but know a bit about their British cousins. In
the lifts there is something called a "knock-off pin", in the picture it is marked
with a red line. This catches the edge of the piston as it reaches the fully raised
position and moves the control valve and linkage into neutral. If you need to use,
say, constant pumping, you take the control lever beyond the top stop on the lever
quadrant which allows the lift to bypass this function.

It is possible to, incorrectly, adjust the internal linkage to allow this to happen
without going beyond the top quadrant stop.

Click to expand...

Very interesting! Ok, looks like I'm diving back in to check this again. Thank you for the feedback. I do know that I had seen a pin sticking out on my unit as well.

The problem is in the adjustment. It's still trying to lift while the piston is at full travel. The pressure relief valve should be squealing as it let's that pressure off. That's high pressure fluid through a small exit, quickly overheats the oil. Really hard on the engine and camshaft gears. I have one that does that, for now I put a level arm stop ot the top so it won't go to that squeal point. I have also adjusted one where the arms don't quite go all the way down. I don't know what to tell you to adjust but you might be able to adjust the turnbuckle on the control valve through the pto handle cover. That's what i'm going to try when I get around to it. Post back here when you get it fixed. Someone else might have the same problem.

(quoted from post at 00:58:36 12/10/20) The problem is in the adjustment. It's still trying to lift while the piston is at full travel. The pressure relief valve should be squealing as it let's that pressure off. That's high pressure fluid through a small exit, quickly overheats the oil. Really hard on the engine and camshaft gears. I have one that does that, for now I put a level arm stop ot the top so it won't go to that squeal point. I have also adjusted one where the arms don't quite go all the way down. I don't know what to tell you to adjust but you might be able to adjust the turnbuckle on the control valve through the pto handle cover. That's what i'm going to try when I get around to it. Post back here when you get it fixed. Someone else might have the same problem.

Click to expand...

This is exactly my thoughts and what I'm sure is happening, thank you for putting it into better words and explaining it this way. Mine isnt making any squealing noise, so I'm thinking that it might be Just past the point of "too far adjusted" and maybe not full blown pressurizing the relief valve, but enough to be overheating over time. I'm not exactly sure what it is that I adjusted too far because I literally adjusted the rod gaps by the book and to exact specs. I'll probably open it back up and check the relationship of the pin that was mentioned. I'll definitely update this thread as we work thru it. Unfortunately the gasket kit wont be here for a week or so, and in the meantime as soon as I fire the unit up, oil is spraying out of the pump at a tremendous rate. Testing will have to wait, haha.

If its squealing then it's not very loud. At idle you can stick a big screwdriver or pipe to your ear and place it at the bottom of the tranny where the pressure relief valve is located. It could also be bypassing at the blowoff valve under the rectangle shaped 4 hole plate where remotes mount to. As long as you ran it it might have trashed the blowoff valve. I always thought it a little strange that they would put it there but it actually screws into the cylinder there.

Hi all,

Checking in as I finally had time to dive back in on the 841's three point lift system.
Turns out Majorman nailed it! I pulled off my side plate for my PTO lever, stuck my little scope camera up there while the three point was in full lift position, and sure enough there was a small gap between the piston and the pin that kicks the arm. It was out of adjustment for sure. I'm really baffled on this one because I had set the gaps on the rod according to the book and also watched a few youtube vidoes on procedures to be sure that I had set the lift arms in the proper position, the draft/position selector on the proper setting, and the lift lever in the proper position while making the necessary adjustments. I went back thru the whole thing and tweeked a few adjustments to where the piston kicks the valve just before the lift arms hit full travel. After doing this, The gaps for the valve body piston aren't exactly what specifications in the book calls for, but the hydraulic system is happy now and working as it should without heating up.
Thank you again to all that chimed in!!!

(quoted from post at 23:29:59 01/30/21)
Hi all,

Checking in as I finally had time to dive back in on the 841's three point lift system.
Turns out Majorman nailed it! I pulled off my side plate for my PTO lever, stuck my little scope camera up there while the three point was in full lift position, and sure enough there was a small gap between the piston and the pin that kicks the arm. It was out of adjustment for sure. I'm really baffled on this one because I had set the gaps on the rod according to the book and also watched a few youtube vidoes on procedures to be sure that I had set the lift arms in the proper position, the draft/position selector on the proper setting, and the lift lever in the proper position while making the necessary adjustments. I went back thru the whole thing and tweeked a few adjustments to where the piston kicks the valve just before the lift arms hit full travel. After doing this, The gaps for the valve body piston aren't exactly what specifications in the book calls for, but the hydraulic system is happy now and working as it should without heating up.
Thank you again to all that chimed in!!!

Click to expand...

Thanks for posting back! This is good to know.