800 hydraulic pump confusion....problem?

[Centerline]

I bought an 850 about 2 years ago and the hydraulics have been hit and miss as to when and if it starts to work.... but when it worked, it seemed to work fine without any noticeable issues...
Ive never had reason to try using the draft control, but the draft lever was definitely wrong, as it would go up vertically, and down parallel with the gasket, but not downward.....
its supposed to go downward for draft control and horizontal for position control.....

the last few times I ran the tractor, using the FEL, the 3pt lift hasnt functioned at all, but just useless iron swinging around back there......

so 2 weeks ago I tore it apart and checked things out and ordered all the parts I needed....

the pivot pin was worn severely so I replaced it (someone had swapped the pin end for end some years ago, as the hidden end in the lever was worn also)...

the piston seal had been replaced, but the leather back up ring appeared to be original and was hard and crispy and worn thru... or possibly had been sheared off as the piston was inserted into the cylinder...

im thinking that someone without knowledge or a book to go by had removed the cover and taken it apart to try and fix it by making adjustments, as the main spring yoke was tightened up about as much as it would go, and the turnbuckle was adjusted to try and get it to work better with the worn out pin, as it was quite far out of adjustment, both the [i:503bb2caf3]draft[/i:503bb2caf3] and the [i:503bb2caf3]position[/i:503bb2caf3] settings...

I got the cover assembly all back together with new parts and before replacing the cover, I took the pump off and pressure tested the lines to 60lbs, and which have no leaks at this time....

I took the VANE pump apart for inspection and found the shaft seal had worn a groove in the shaft, so I replaced the shaft, seal and bearing.... and cleaned the flow control valve. the vanes are moving freely in the rotor and were out against the walls of the cam ring.... there is no noticeable wear on the rotor, vanes, cam ring or end caps....

after getting the adjustments all correct and the tractor back together, the pump refuses to prime, even at max throttle...
there is no oil flow at all... Ive had the pump off and back on 5 times so far, trying different things, double checking my work and trying to locate the problem...

so im here looking for input from those who have had similar issues on why it wont prime up.... all the orings are new and of the correct size.

AND the confusing part...
when I took the pump off the tractor, I marked it with a paint marker so that I could get it back together in the same way it came apart...
the ARROW on the cam ring was pointing up in the direction that the pump turns, BUT the book shows it pointing downward in the opposite direction of the rotation.... I have tried switching the cam ring, but still no prime... which is the proper way for the arrow point? and where else to look for the air leak that is preventing it from priming.
thanks for any help you may be able to offer....

This post was edited by Centerline on 09/29/2023 at 06:54 pm.

 

[Hemmjo]

I have the piston type pump, so this is just question/suggestion. My pump has a port to bleed air out f the pump. I have had to use that two times. One when I had a hydraulic leak, and sucked air into the pump. It would not prime after that until I removed the plug. Second time I had to remove the the pump to access the oil pressure fitting behind it. Had to remove the plug then also.

Does yours have a port to bleed air?

 

[JMOR]

(quoted from post at 21:51:31 09/29/23) I bought an 850 about 2 years ago and the hydraulics have been hit and miss as to when and if it starts to work.... but when it worked, it seemed to work fine without any noticeable issues...
Ive never had reason to try using the draft control, but the draft lever was definitely wrong, as it would go up vertically, and down parallel with the gasket, but not downward.....
its supposed to go downward for draft control and horizontal for position control.....

the last few times I ran the tractor, using the FEL, the 3pt lift hasnt functioned at all, but just useless iron swinging around back there......

so 2 weeks ago I tore it apart and checked things out and ordered all the parts I needed....

the pivot pin was worn severely so I replaced it (someone had swapped the pin end for end some years ago, as the hidden end in the lever was worn also)...

the piston seal had been replaced, but the leather back up ring appeared to be original and was hard and crispy and worn thru... or possibly had been sheared off as the piston was inserted into the cylinder...

im thinking that someone without knowledge or a book to go by had removed the cover and taken it apart to try and fix it by making adjustments, as the main spring yoke was tightened up about as much as it would go, and the turnbuckle was adjusted to try and get it to work better with the worn out pin, as it was quite far out of adjustment, both the [i:dab04087ce]draft[/i:dab04087ce] and the [i:dab04087ce]position[/i:dab04087ce] settings...

I got the cover assembly all back together with new parts and before replacing the cover, I took the pump off and pressure tested the lines to 60lbs, and which have no leaks at this time....

I took the VANE pump apart for inspection and found the shaft seal had worn a groove in the shaft, so I replaced the shaft, seal and bearing.... and cleaned the flow control valve. the vanes are moving freely in the rotor and were out against the walls of the cam ring.... there is no noticeable wear on the rotor, vanes, cam ring or end caps....

after getting the adjustments all correct and the tractor back together, the pump refuses to prime, even at max throttle...
there is no oil flow at all... Ive had the pump off and back on 5 times so far, trying different things, double checking my work and trying to locate the problem...

so im here looking for input from those who have had similar issues on why it wont prime up.... all the orings are new and of the correct size.

AND the confusing part...
when I took the pump off the tractor, I marked it with a paint marker so that I could get it back together in the same way it came apart...
the ARROW on the cam ring was pointing up in the direction that the pump turns, BUT the book shows it pointing downward in the opposite direction of the rotation.... I have tried switching the cam ring, but still no prime... which is the proper way for the arrow point? and where else to look for the air leak that is preventing it from priming.
thanks for any help you may be able to offer....

This post was edited by Centerline on 09/29/2023 at 06:54 pm.

o bleed plug on vane pump.. Some have success by applying compressed air into sump via the fill port to force fluid into pump.

 

[Gene in Mi]

When I rebuilt the vane pump on my Jubilee I had the same trouble priming the pump.
Pressurizing the chamber through the dipstick hole did not work.

I finally got it by looseninging the suction line at the pump while applying air at the dipstick until I knew I had fluid to the pump. (Engine off) Then I loosened the pressure line at the pump and started the engine while applying air. Success!

The arrow on the cartridge MUST match pump rotation.

 

[Centerline]

UPDATE......

I finally got the pump to prime....

what I found is that the oil setting in the pressure tube would not allow the air in the pump to displace it... which, I took the pump off and blew the oil out of the pressure tube and when i reinstalled the pump, it took immediately....

this priming issue may never be a problem again, but due to the trouble I went thru, I decided to INSTALL a BLEED screw....

I got the smallest diameter brake bleed screw from napa, and the tap needed for it, and then drilled PARTWAY into the mounting flange of the manifold (in the recess between the mounting stud holes), aiming towards the pressure tube, and then tapped the hole for the bleeder..... then, after insuring the bleeder fit nicely, I drilled a small hole thru the bottom of the tapped hole into the pressure side of the manifold.... then installed the bleed screw... it seems to work well, but wont know for sure until next time I have a problem....
the manifold flange is the only reasonable place for a bleed screw in the system near the pump, and the ONLY part of the manifold that is thick enough to allow the installation of a bleed screw......

for anyone reading this that may ever have the hydraulics stop working, or hydraulics that only work sometimes, the problem will most likely be found in the flow bypass valve in the cylinder casting... the one hidden under the cover right next to the control valve
the shuttle/spool sticks due to contaminate build up, and not allow the pressure to build in the cylinder....

this NEEDS to be removed and the bore polished to remove any minor corrosion or debris that may hinder the free movement of the spool... it needs to shift [i:65caf53816]easy[/i:65caf53816] in the bore to work properly.......
AND, for those who may care about replacing the seal on the spool, it takes a SPECIAL sized oring from ford/new holland, which may or may not be the same as a QUAD RING.... but my local hydraulic shop couldnt come up with an oring to fit, but they found that a $1.65 QUAD ring fits perfectly....

as to the direction that the arrow on the pump ring, the GENUINE ford manual is WRONG, as the arrow must point UP in the direction that the pump shaft spins.. NOT down as shown in the ford shop manual.....


its all back together and working better than it has since ive owned it....
now that it works dependably every time, AND will hold my 60" brush mower suspended for at least 4 days without dropping more than a 3" during that time.....

This post was edited by Centerline on 10/05/2023 at 10:21 am.