Last straw hydraulic problem on JD 410 backhoe

I replaced the diff housing on a JD410 backhoe. The backhoe itself came off in this process (long story).

Either way I get her running and hydraulics are good for like 20 minutes then a hose blows. Replace the hose and now no hydraulics.

What I have done so far.

Cleaned :
Hydro filter pressure release.
Tranny pressure release.
Hyrdo pressure release.
Pump filter screen
Tranny screen.

Funny thing is I can add shims to the pressure release (takes a lot) to get it to 1000 psi. With the shims that were in there before it was at 500PSI. I cannot get anymore shims in there to go higher then 1000psi. And not much more movement at 1000psi.

Backhoe pads can go up and down but slow They can lift the machine. Tilt on loader works OK but slow. Boom on loader hardly moves. Pump is about 2 years old and not many hours on it.

Hose blew when I had the backhoe off and the lines plugged. I have since been able to get backhoe attached. I assume I got the two hoses that attach to the backhoe correctly as the controls move in the correct direction.

Other then that I am at a loss and have spent more time chasing this hydro problem then replacing the rearend. Frustrating as the hydraulics worked fine before the hose blew.

Any other ideas before I bury this thing? :)

Is it possible that there is some type of airlock in the system? I mean it ran fine before I replaced the hose. I know the system will purge the air out it self..... ...but.

Thanks in advance,
Chris

I am waiting to find a time to pull the clutch control valve out and clean that out.

Chris

This afternoon I was able to make some progress. I was able to cap off the pump. I was able to do this at a connection (not a normal connection as it is a repaired pipe) on the pump output. At this point it was capped, the aculumlator and the power steering was still getting pressure from the pump. When running pressure jumped right up to 2200psi. :)

So that rules out the pump or anything related up front. Including the power steering and the acumulator. Well I assume such.

About the only thing I think I have left is the clutch control valve. It was on the lower right of the clutch unit as you look at it from the front of the machine. Nothing unusual about it.

In looking at the manual, it seems like I should be taking the complete clutch control unit out and give it a good cleaning.

Or is there a better place to look?

Thanks again,
Chris

In reference to the "cracking the line and seeing the flow". I assume I should still be doing this even after capping the line showed pressure. I might do this before I takle the clutch control valve.

The valve I refered to shimming was the pressue relief valve.

Thanks,
Chris

If that checks out, then I think I will take your advice and pull the pressure reilef valve again.

Thanks,
Chris

Thanks, I did just as you suggested and it looks like the pump is fine.

I am glady making not that you are in MA as well. :)

I only wish there was an easy way to get to the stroke control valve. I might have to take the pump out or drop the front end to get to it.

I will take the great help I got here and report back.

Thanks all

Good point. Do you think that would shut the whole machine down? I assume so now that you mentioned it.

I wish it was that easy. I spent 1.5 more time tracking this problem down then I did with the rear end. :)

Thanks again

If you are refering to the "transmission relief valve" right near the transmisson filter, I already gave that a good cleaning. Nothing really dirty about it. :(

Next.

Thanks again,
Chris

Well if i was able to shim the pressure adjust and get another 500psi out of the pump, I think it is ok.

Chris