Hydraulic pressure on jubilee

T L

Member
Where do I check the hydraulic pressure on a jubilee? What should the pressure be and when?
 
I think you have to put a tee in the output side of the pump and plumb your gauge into that tee. I seem to recall seeing folks recommend a 3000 psi gauge and around 2500 psi pressure from the pump but I could be mistaken.
 
(quoted from post at 20:58:48 03/01/17) I think you have to put a tee in the output side of the pump and plumb your gauge into that tee. I seem to recall seeing folks recommend a 3000 psi gauge and around 2500 psi pressure from the pump but I could be mistaken.
o, but I'll try to straighten you out tomorrow.
 

2000 PSI. Provided you don't have a remote valve on your tractor, there is an accessory plate on your lift cover. This will be under the front of the seat. There's a pipe plug in that plate. Plumb a 3000 PSI gauge into that port. Then tie down the the three point arms and place the system on demand to read pressure output.
 
not even close!

You'd be hard pressed to T out of a jube pump.

Larry got it correct. Gauge in accy cover under seat, chain lift arms down, raise 3pt, then up rpm to rated speed.
 
Thanks for all the information. I had put the gauge there and didn't see any pressure, yet the arms go up and down fine. I will chain the arms down and see what pressure I have. The problem I am having is the arms go to what ever position I lift the lever to but when it reaches that level it slowly goes down an inch or so and then goes back up to the position. It seems like a valve is not working correctly. I have rebuilt the pump and gone through the lift cover with every available information I could find.If I shut the tractor off and put pressure on the arms they go down and I have looked in the filler hole and there isn't any oil coming from the cylinder or gasket area.
 
Had you provided that use full info earlier, we coil have answered straight out.

Lifting, then leakdown, then circuit regeneration. The lag in leak to regen is usually slop/play in the linkages.

The reason you saw little pressure when you had the gauge there before, is you didn't chain the lift arms, thus very low pressure was needed to lift them, like 60 maybee.. And on a 3000 psi gauge, 60 is almost no needle movement.
 
Thanks for the reply. You are right about me not knowing about chaining the arms, I would have never thought of that. There is a lot about this tractor I am not sure of. I just purchased it and it has a piston pump and new pressure lines on it as well. When you say slop or play in the linkages, where are these located. I changed the pins in the top cover and inspected everything according to a chart I found on the internet?
 
Everything under the hydraulic cover seems to be in great shape.I purchased the ford hydraulic repair dvd and watched it several times. That was very helpful. How would I check leak down in the pressure circuit?
 
Did you make the correct measured adjustments to the linkage?

Various places that could leak. Lift piston, check valve, various orings on the cyl to cover , etc
 
Yes I made all the adjustments and replaced all o-rings, gaskets, and piston leather and seal. How do you check the check valve?
 
" How would I check leak down in the pressure circuit?"
Well, no need to check for leak down, as you have already verified that it exists. "If I shut the tractor off and put pressure on the arms they go down and...."

...now you just need to isolate as to where. Only you have access to the machine, I'm not there.
 
(quoted from post at 05:16:55 03/03/17) " How would I check leak down in the pressure circuit?"
Well, no need to check for leak down, as you have already verified that it exists. "If I shut the tractor off and put pressure on the arms they go down and...."

...now you just need to isolate as to where. Only you have access to the machine, I'm not there.
ome places to examine:
 
I have looked into the fill cap hole with a flashlight and have someone push the arms down there is no oil coming from the cylinder or gasket area. I think it must be a valve. How can I figure out which one?
 
jmor posted the diagram for you to see the pressure leak paths. If nothing I coming out cyl mouth, check valve is next area, then control valve.
 
Thanks for the advice. It is in the teens here in NY tonight so it will be a few days before I go back into my shop.Is there a way to check the check valve and control valve or do I need to replace them 1 at a time until the problem is found.
 
Isolate leak first, then replace parts.

A leak big enough to drop the lift will be leaking a few ounces of oil, IE the volume of the lift cyl
 
Observation. Which albeit is harder, with the cover on.

I've ran a hundred series on a stand, top cover only, with a drain pan, and a tapped fitting in the hyd port on the underside of the top cover. With a NAA, YOU HAVE THE BACKPREDSURE VALVE TO DEAL WITH.

Could run it on air and look for foaming/ feel for air.
 
Thanks, I will pull the cover back off and try that. I appreciate your help. I have been working on this for several weeks.
 
Thanks JMOR for the diagram, it is very helpful in trying to understand the system.
 

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