851 hydraulic woes

overfordy

New User
Hi all,

Lets start with what i have done. I took a couple of years rebuilding this tractor the hydraulic system has been empty the whole time and the pump was removed. Finally got her put back together rebuilt motor and all runs great. But when it was first started after rebuild the lift arms went up and stayed there no matter where the control lever was at can't even push them down when the control lever is in the down position. I removed the lift cover from the tractor and down they went. i inspected everything looked fine put it back together now they wont go up. Pretty sure my pump is primed took out the plug and fluid would pump out of it. took off the little square cover on top of the lift plate to see if i get pressure at the inlet port. With the tractor running I can stop the flow with my finger. Is my pump bad or might it be something else.

Thanks
 
Type in the search bar Ford hydraulic lift problem, it will pull up old posts. Its not good to leave them sitting around with NO oil as water condensation will rust a lot of stuff but water goes to the bottom of the sump. As long as it has oil in it the water will be covered and it cant oxidize anything without air. Any further condensation stays in the sump.
 
How did the lift work before you began the overhaul?

Your symptoms are typical of a sticky unloader valve. As the tractor has been laid up for some time, you may just need to cycle the lift to get it moving again.

If lift won't go down, move the Position Control lever to Draft and the arms should drop.

What type of hydraulic oil are you using?
 
If you actually took the ~3x3" accessory plate off and covered the pump output with your thumb and could stop flow, then there is a pump or prime, or piping problem. No unloader, control, etc. valve between that point and the pump.
 
Thanks for the replies. I took the plug out of the pump and poured fluid into it turned the engine over and it squirted fluid out so I assumed it was primed and I could stop the flow with my thumb under the 3x3 plate output pipe.
 
(quoted from post at 12:17:16 02/21/18) Thanks for the replies. I took the plug out of the pump and poured fluid into it turned the engine over and it squirted fluid out so I assumed it was primed and I could stop the flow with my thumb under the 3x3 plate output pipe.

After the tractor is running, loosen the plug in the pump but do not remove it, and see if fluid comes out, and if so are there any air bubbles in the fluid. If there are air bubbles, leave it loose until the air bubbles are gone and then tighten it up.
 
OK I loosened the plug on top of pump ran it until no air bubbles. The lift arms went up and are stuck in that position
the case is full of fluid after the engine runs for about 30 seconds I get a loud rattle the pump is full of air again bleed off the air rattle goes away 30 seconds later rattle comes back lift arms still stuck will not come down.
 

OK I loosened the plug on top of pump ran it until no air bubbles. The lift arms went up and are stuck in that position
the case is full of fluid after the engine runs for about 30 seconds I get a loud rattle the pump is full of air again bleed off the air rattle goes away 30 seconds later rattle comes back lift arms still stuck will not come down.
 
(quoted from post at 18:03:29 02/21/18)
OK I loosened the plug on top of pump ran it until no air bubbles. The lift arms went up and are stuck in that position
the case is full of fluid after the engine runs for about 30 seconds I get a loud rattle the pump is full of air again bleed off the air rattle goes away 30 seconds later rattle comes back lift arms still stuck will not come down.
emove plug in top of accessory plate & if arms drop, then it is a hydraulic problem, if not it is mechanical problem. Be prepared for oil bath.
 

Remove plug in top of accessory plate

Question, is that were you check hydraulic pressure (not that it has anything to do with his issue just asking)...
 
(quoted from post at 04:09:03 02/22/18)
(quoted from post at 18:03:29 02/21/18)
OK I loosened the plug on top of pump ran it until no air bubbles. The lift arms went up and are stuck in that position
the case is full of fluid after the engine runs for about 30 seconds I get a loud rattle the pump is full of air again bleed off the air rattle goes away 30 seconds later rattle comes back lift arms still stuck will not come down.
emove plug in top of accessory plate & if arms drop, then it is a hydraulic problem, if not it is mechanical problem. Be prepared for oil bath.

I would put a spicket/drain valve on it no way I like getting oil on me if I can help it... I do have priorities and one of'em is working clean.. If I could only train my help to work clean...
 
I have taken that plug out and it did not relieve the pressure holding up the arms. The only way the arms go down is if i totally remove the lift cover then i can push the arms down forcing out the fluid probably through the inlet port.
 
(quoted from post at 23:09:07 02/21/18) I have taken that plug out and it did not relieve the pressure holding up the arms. The only way the arms go down is if i totally remove the lift cover then i can push the arms down forcing out the fluid probably through the inlet port.
n that case, I would suspect that by removing the cover, that you are removing a "mechanical lock up", as the only thing between that accessory plate plug and the lift cylinder is a "pipe" (really passages in the plate & castings). You could apply pressure to that plug & cause lift......the path is that direct.
 

Have you taken the fill plug out and looked at the linkage and looked to see if the linkage is moving the control valve in and out as it should with the quadrant/lift control leaver... Remove fill plug under seat the linkage/control valve is EZ to see....
 
Had some good luck today I got it to work. took the lift cover off to inspect the control valve could not see good enough through the fill hole. the valve ram was stuck in the lift position, took off the retaining plate and worked it out, cleaned it and the cylinder put it back together and it moved freely. Put the lift cover back on started her up bled the air out and it works. though it kinda pulsates on the way up. Is this normal?

Thanks
 
(quoted from post at 19:40:37 02/22/18) Had some good luck today I got it to work. took the lift cover off to inspect the control valve could not see good enough through the fill hole. the valve ram was stuck in the lift position, took off the retaining plate and worked it out, cleaned it and the cylinder put it back together and it moved freely. Put the lift cover back on started her up bled the air out and it works. though it kinda pulsates on the way up. Is this normal?

Thanks
lad you got it working! However, this part still makes no sense, "I have taken that plug out and it did not relieve the pressure holding up the arms.". Such is life, I guess.
 

it kinda pulsates on the way up. Is this normal?

No if it works good leave it B... The last one i worked on did that with no load on the arms, it was barely noticeable with a normal load on the lift...

My personal opinion if you want to chase it the lift cover will have to come back off you will need to dissemble the lift cover replace seals and adjust... The lift cover has ware items I go get them first...
 
(quoted from post at 05:56:35 02/23/18)
(quoted from post at 19:40:37 02/22/18) Had some good luck today I got it to work. took the lift cover off to inspect the control valve could not see good enough through the fill hole. the valve ram was stuck in the lift position, took off the retaining plate and worked it out, cleaned it and the cylinder put it back together and it moved freely. Put the lift cover back on started her up bled the air out and it works. though it kinda pulsates on the way up. Is this normal?

Thanks
lad you got it working! However, this part still makes no sense, "I have taken that plug out and it did not relieve the pressure holding up the arms.". Such is life, I guess.

I don't think that's the way you live life,,, If confronted with that issue I don't think you would just give up,,,, Your question deserves a answer...
 
(quoted from post at 21:18:01 02/22/18)
(quoted from post at 05:56:35 02/23/18)
(quoted from post at 19:40:37 02/22/18) Had some good luck today I got it to work. took the lift cover off to inspect the control valve could not see good enough through the fill hole. the valve ram was stuck in the lift position, took off the retaining plate and worked it out, cleaned it and the cylinder put it back together and it moved freely. Put the lift cover back on started her up bled the air out and it works. though it kinda pulsates on the way up. Is this normal?

Thanks
lad you got it working! However, this part still makes no sense, "I have taken that plug out and it did not relieve the pressure holding up the arms.". Such is life, I guess.

I don't think that's the way you live life,,, If confronted with that issue I don't think you would just give up,,,, Your question deserves a answer...
f I were dealing with that tractor, you can be sure I would dig out the answer.!
 

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