JD 410 backhoe, brass flakes in stroke control housing

[texascadillac42]

I have a straight JD 410 backhoe I am working on for my neighbor and am having hydraulic trouble with it. All functions work but are weak and slow.

I have replaced the tranny sump filter, as well as both cartridge hydraulic filters. I have checked the trans filter relief valve, as well as the pressure control valve on right side of trans.

Pressure gauge off of the right side of the hydraulic pump shows 2000 psi with the stroke control adjustment run all the way in. This is with the main pump deadheaded, the pressure readings are the same with the pump plumbed into the system normally.

I checked reverser pressure at the test port on the lower rear portion of the reverser valve on right side of transmission and have 155psi.

The hydraulic pump has been rebuilt by a shop I have used many times with zero issue.

After checking pressures and running stroke adjustment screw in, I pulled the filter (next to stroke control) out of the stroke control housing and found lots of brass flakes on it. The brass flakes had the crankcase outlet valve somewhat bound up. I also removed the stroke control valve and found it to have brass in it as well.

Does this brass indicate that the newly rebuilt hydraulic pump is failing, or was improperly built? Or is it possible to have brass coming from somewhere before the hydraulic pump?

My pump shop tells me that there are zero brass components in the hydraulic pump so the brass must be coming from before.....

Thank you very much for any help you can provide.

 

[lantraxco]

To my knowledge that's correct, nothing but steel and iron in the hydraulic pump, so your brass must be coming from elsewhere.

The transmission and hydraulic filters should be catching the brass, but it kinda depends on where it's coming from.

 

[wrwtexan]

Only two places I know of where brass can come from that I know of in them; brake linings (brass strands in fiber linings) and maybe a differential ring gear side thrust pin.

 

[texascadillac42]

Well I'm glad to hear the shop isn't lying to me. I cleaned everything in the stroke control housing and reassembled it with no change in pressures.

1900-2000psi at idle with no functions being operated. 1450-1600psi when running functions with no load on them. This is with the stroke control screwed all the way in. I am going to replace the stroke control valve as Im told that any kind of wear in the seat area of the stroke control valve will cause low standby pressure. I will update this after changing the valve. Hopefully this will allow the proper standby pressure of 2350psi.

Thanks for the help!