Jubilee Hydraulic system seems to have no Pressure

Jimr

New User
I have a Piston style pump. I have bled the pump using a hose attached to the pump bleeder port and dumped in into the transmission fill hole. Ran the bleed for several minutes. The 3 point lifts but putting my foot on it stops the lift and I get no lift at the end loader at all. The 3 point lift oscillates some when raised. My question is how can I tell if my problem is the pump which seems to be pumping volume but not sure how much, or the Pressure relief valve or the safety valve. If the pressure relief valve or safety valve is stuck open what kind of pressure readings should I get at the pump bleeder port?
 
Maybe someone else will chime in. Someone said to chain the arms down at the end to get a pressure reading at the pump. Make SURE you dont have the lift lever up too far when checking. I believe that pump should put at least 2000 psi, I'd have to check my manual.
 
I hope you misspoke. The bleed hose should be dumping in to the hydraulic fill hole, under the set, right side. Once all air is out of the system, install a gauge in the pump bleed hole, chain the lift arms, down, raise the three point lever up and check the reading on the gauge. Should be close to 2000 lbs, at least 1500. If not, pull the PTO shifter cover, six bolts, and have a look inside for leaks. Maybe report back with findings and further information.
 
(quoted from post at 08:48:32 08/17/17) I hope you misspoke. The bleed hose should be dumping in to the hydraulic fill hole, under the set, right side. Once all air is out of the system, install a gauge in the pump bleed hole, chain the lift arms, down, raise the three point lever up and check the reading on the gauge. Should be close to 2000 lbs, at least 1500. If not, pull the PTO shifter cover, six bolts, and have a look inside for leaks. Maybe report back with findings and further information.

With the pto cover off i get a steady stream of fluid down just inside the cover running about centered on the cover hole. Maybe a 3/16 or 1/4" stream
 

I have a similar problem. My lift works (jumpy) after bleeding the pump but after it sits awhile it won't work until I bleed the pump again.

I also have a leak (dripping) from the control valve retainer plate. The oil seems to be coming out of the hole in the center of the plate and also some from around the control valve where it enters the back plate.

Anyone know what this may imply?

Thanks
 
A small/slow drip at either of those two places (control valve shaft or hole behind unloader valve) may not be of concern, as there are no seals on either, just close fit metal spool to bore.
 
Apparently it is time to replace the o ring and back up washer on the piston in the cylinder and /or replace the gasket between the lift chest and the cylinder assembly.
 
(quoted from post at 05:17:39 08/18/17) Apparently it is time to replace the o ring and back up washer on the piston in the cylinder and /or replace the gasket between the lift chest and the cylinder assembly.

Was this in reply to me or to JMOR?

Yes I had miss spoke earlier when I said I bleed it into the transmission.

I have remove the Safety Relief Valve and it looked like some one had been trying to make it work before me. I have ordered a new one. I didn't see any turbulence of the oil in the reservoir so I assume the pressure relief valve is holding alright. But still wondering if the small steady stream of oil running down inside the case right inside the PTO cover hole is normal or could that be coming from the bad safety relief valve?

Lastly what type of fluid replaces the A type the book calls for. I'm thinking it is replaced by Dextron. Will a universal Transmission multi purpose transmission fluid work alright?
 
Lastly what type of fluid replaces the A type the book calls for. I'm thinking it is replaced by Dextron. Will a universal Transmission multi purpose transmission fluid work alright?

That old specification has been superseded a few times over the years. The current spec is the Ford/New Holland M2C134D spec. Any UTF that says on the label that it meets that spec will be fine.
 
(quoted from post at 13:33:09 08/17/17) A small/slow drip at either of those two places (control valve shaft or hole behind unloader valve) may not be of concern, as there are no seals on either, just close fit metal spool to bore.

Should oil always be flowing from the back pressure valve no matter what position the lift is?
 
(quoted from post at 11:13:44 08/18/17)
(quoted from post at 13:33:09 08/17/17) A small/slow drip at either of those two places (control valve shaft or hole behind unloader valve) may not be of concern, as there are no seals on either, just close fit metal spool to bore.

Should oil always be flowing from the back pressure valve no matter what position the lift is?
ertainly not a "flow", but maybe a drip. Flow in hold, lower, but no flow in lift.
 
(quoted from post at 10:47:02 08/18/17)
(quoted from post at 11:13:44 08/18/17)
(quoted from post at 13:33:09 08/17/17) A small/slow drip at either of those two places (control valve shaft or hole behind unloader valve) may not be of concern, as there are no seals on either, just close fit metal spool to bore.

Should oil always be flowing from the back pressure valve no matter what position the lift is?
ertainly not a "flow", but maybe a drip. Flow in hold, lower, but no flow in lift.

Ok, I put a gauge in the pump outlet. When lifting a bush hog the pressure went to about 1200 psi. Right at the end of lifting it read about 1400 psi then went back to 1200 and stayed there while the lift was in the raises position.

When lowering the lift the pressure dropped to 0 psi until it reached a preset point then it increased to about 800 psi to hold the weight at that position.

At the lowered position of course it went to 0.

Is this normal except for the pressure reading should be higher?

I am trying to figure out how the hydraulics operate (oil flow/valves) during each phase of lowering and raising.

When the tractor is first started with the lift in the lowered position the pump is sending oil through what valves? I have read the pressure is about 45 psi in the back pressure valve. Should this pressure stay at this when the tractor is shut off and remain until it is restarted to keep the pump primed or does the pump have to pull the oil from the sump to prime itself again. Seems to me if the latter is the case then there will be air in the suction line from oil draining back to thr sump.

I probably have this wrong. Can someone tell or direct me to a where I can find out how and where the oil flow at each cycle of the lifting, hold and lowering of the lift?

Thanks
Cgun
 
(quoted from post at 22:52:50 08/19/17)
(quoted from post at 10:47:02 08/18/17)
(quoted from post at 11:13:44 08/18/17)
(quoted from post at 13:33:09 08/17/17) A small/slow drip at either of those two places (control valve shaft or hole behind unloader valve) may not be of concern, as there are no seals on either, just close fit metal spool to bore.

Should oil always be flowing from the back pressure valve no matter what position the lift is?
ertainly not a "flow", but maybe a drip. Flow in hold, lower, but no flow in lift.

Ok, I put a gauge in the pump outlet. When lifting a bush hog the pressure went to about 1200 psi. Right at the end of lifting it read about 1400 psi then went back to 1200 and stayed there while the lift was in the raises position.

When lowering the lift the pressure dropped to 0 psi until it reached a preset point then it increased to about 800 psi to hold the weight at that position.

At the lowered position of course it went to 0.

Is this normal except for the pressure reading should be higher?

I am trying to figure out how the hydraulics operate (oil flow/valves) during each phase of lowering and raising.

When the tractor is first started with the lift in the lowered position the pump is sending oil through what valves? I have read the pressure is about 45 psi in the back pressure valve. Should this pressure stay at this when the tractor is shut off and remain until it is restarted to keep the pump primed or does the pump have to pull the oil from the sump to prime itself again. Seems to me if the latter is the case then there will be air in the suction line from oil draining back to thr sump.

I probably have this wrong. Can someone tell or direct me to a where I can find out how and where the oil flow at each cycle of the lifting, hold and lowering of the lift?

Thanks
Cgun
ill try to post diagrams Sun eve, but not home now
 
(quoted from post at 00:41:34 08/20/17)
(quoted from post at 22:52:50 08/19/17)
(quoted from post at 10:47:02 08/18/17)
(quoted from post at 11:13:44 08/18/17)
(quoted from post at 13:33:09 08/17/17) A small/slow drip at either of those two places (control valve shaft or hole behind unloader valve) may not be of concern, as there are no seals on either, just close fit metal spool to bore.

Should oil always be flowing from the back pressure valve no matter what position the lift is?
ertainly not a "flow", but maybe a drip. Flow in hold, lower, but no flow in lift.

Ok, I put a gauge in the pump outlet. When lifting a bush hog the pressure went to about 1200 psi. Right at the end of lifting it read about 1400 psi then went back to 1200 and stayed there while the lift was in the raises position.

When lowering the lift the pressure dropped to 0 psi until it reached a preset point then it increased to about 800 psi to hold the weight at that position.

At the lowered position of course it went to 0.

Is this normal except for the pressure reading should be higher?

I am trying to figure out how the hydraulics operate (oil flow/valves) during each phase of lowering and raising.

When the tractor is first started with the lift in the lowered position the pump is sending oil through what valves? I have read the pressure is about 45 psi in the back pressure valve. Should this pressure stay at this when the tractor is shut off and remain until it is restarted to keep the pump primed or does the pump have to pull the oil from the sump to prime itself again. Seems to me if the latter is the case then there will be air in the suction line from oil draining back to thr sump.

I probably have this wrong. Can someone tell or direct me to a where I can find out how and where the oil flow at each cycle of the lifting, hold and lowering of the lift?

Thanks
Cgun
ill try to post diagrams Sun eve, but not home now
2285.jpg
 

Thanks for diagrams.

How does the pump stay primed when the tractor is turned off?
If it doesn't then how does it prime when tractor is started?

Thanks
Cgun
 
Cgun,
Think of a straw in a drink. If you put your finger on the end and pull it out, the liquid remains at the same level. (just like when the tractor is off)

Now put a needle hole in the straw. If you pull hard enough, you can get the liquid up. as soon as you stop, the fluid flows back into the container. This is like if there is an air leak anywhere in the system.

Does that make it any clearer. I hope so.

Keith
 
Yes, I understand that principle. So the leak would be in the suction section of the system. Which could be the suction line from sump to pump inlet or in the pump seal.

Cgun
 
I have the Hydraulics working now. I understand I can only use the end loader when I have the 3 point arms chained down. My question is, the loader only works if the lift control is raised to lift the 3 point. Is this correct?
The service manual says to not to hold the control lever in the lift position for more than 10 seconds with the arms chained down as it might damage the pump. So am I doing something wrong or do I operate the end loader with the control lever in the lift position?
 

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