Rear hyd pump cracked twice

[Jumpin92]

I have a 2003 tc55da with ehss . The rear hyd pump just inside the right tire has cracked the head two times now. The tractor has a mere 504 hours on it. It happens just driving around without any equipt. Running. I.e. pto or bucket. This is the second time on August 23rd. So this time I put a pressure gauge in line just outside of forward line which leads to the ehss block I believe. Since this is the line directly above the cracked area. It reads about 200 at idle and around 1000 when I rev it to 2500 rpm s . Is this normal. The dealer could only find a service bulletin on a screen downstream of my guage. I removed and cleaned it this time as I did not know about it before. What do you think? Any one.

 

[J_J]

A cracked pump is usually caused by pressure, and this high pressure is caused by deadheading something.

I would suggest putting a relief valve across the pumps OUT port and run the relief flow to tank.

Can you provide a flow path for this pump. Otherwise, what is it designed to do?

I believe your hyd system is open center, and therefore the fluid must flow at all times. Usually a valve will have a relief valve set to protect the pump against high pressure.

 

[Jumpin92]

A cracked pump is usually caused by pressure, and this high pressure is caused by deadheading something.

I would suggest putting a relief valve across the pumps OUT port and run the relief flow to tank.

Can you provide a flow path for this pump. Otherwise, what is it designed to do?

I believe your hyd system is open center, and therefore the fluid must flow at all times. Usually a valve will have a relief valve set to protect the pump against high pressure.

Sounds right. I do not know yet what this pump operates. So deadheading is possible but from what is my ? Now that I have a guage on it I will
LEarn more hopefully. Where can I find a basic relief valve. Will a relief from a pressure washer work?

 

[J_J]

Surplus Center - 1/2 NPT 30 GPM 500-1500 PSI HYD CUSHION VALVE

 

[Jumpin92]

Surplus Center - 1/2 NPT 30 GPM 500-1500 PSI HYD CUSHION VALVE

It controls the ehss and I have a schematic. I believe the relief valve is jammed partially open . The psi is low at idle and high at rpm. I must clean the relief valve will have to update when that is done.

 

[Jumpin92]

It controls the ehss and I have a schematic. I believe the relief valve is jammed partially open . The psi is low at idle and high at rpm. I must clean the relief valve will have to update when that is done.

I have got everything cleaned and done lots of troubleshooting with psi guage. The psi is high and I disassembled the relief valve and cleaned . No help. The relief is a two stage relief and no fluid would flow out of the relief hose at any rpm. So I removed the second stage of the relief and it runs at 500 max now at max rpm, oil flows out of relief finally. All is not good though, it now when warm, kicks out of gear like I stepped on the clutch . I believe the relief valve in it is relieving but the pressure is not going down on the guage I installed? Reving the engine does not help. The only thing that helps is when I shut off the engine and restart it. Then it will go about 100 ft before it kicks out again. Am going to try shimming the spring witH washers to increase the relief psi on the main relief that is left in it. Seems like a Design flaw to me.they have a service bulletin out for hyd pump failure. It blames it on a in line screen that they figure is plugging. I cleaned the screen while replacing the pump, it appeared clean though and psi is only affected by relief now.
New holland will not give any direct assistants other than to tell me to bring it to dealer. Already bought two hyd pumps at 750 each and dealer is 40 miles away. That's a large towing bill. Trying to get through it. That pillow seems lime quick fix if I could find a mounting place for it. Really would like new holland to step up. 800 number is a joke.

 

[oldnslo]

Jumpin,
What do you mean by "two stage" relief? Is this a pilot operated relief where the small pilot stage controls the main stage or a dual pressure relief where the second stage increases the working pressure on the first stage usually by adding pressure to the first stage spring chamber.

Is EHSS electric hydraulic shuttle shift? If yes I would use caution in adjusting these pressures or you can ruin these clutches.