215B Excavator - Track not working in reverse

[Jamieb34]

Hey,
Trying to help my father with his 215B excavator 9YB serial.
When going forward the machine will track fine and straight, however when reversing the left track does not turn so the machine turns to the right.
I swapped the 2 hoses on the track motors over from left motor to right motor which them moved the problem to the Right side, then i swapped them back and the problem was back on the left side so i know the issue is not in the motor or brakes themselves.
I removed the pilot hoses off the main control valve and measured the pilot pressure going to the valve when the foot levers are pressed down which was 300PSI. (The gauge was installed Instead of the valve, not inline with it)

I then removed the spool for the L/H track and inspected it and could not see anything wrong with it. Regardless i swapped the Left and right track spools, I removed the spools from the spring side since the tang side is in the guts of the machine and access is difficult so i am not sure what is in that side and have not inspected it.
I also removed what i imagine to be a relief valve that is mounted near the spring side of the track spools, it also looked fine but i still swapped the left and right side around. I havent had a chance to test since swapping spools since the hydraulic oil drained but i dont have much confidence that the issue is in the spools.

The stick cylinder also creeps very quickly, i have not had a chance to check this issue yet but am told the issue is intermittent to doubt the cylinder is bypassing,

Appreciate any help,
Cheers

 

[uffex]

Good day Jamie
Compliments you are being very thorough from what you have written you have isolated the issue to the control valve - relief valve but you have not tested the machine I suggest you treat the arm cylinder as a separate issue but this could be relative if the machine has some kind of contamination issue. You will rarely be able to see any kind of spool damage as this is pretty hard mostly the damage will be in the valve block casting (Soft stuff). One of those little cameras that fit to the phone are a good tool to have.A couple of files that may help.
Kind regards
Uffex

 

[Jamieb34]

Thanks,
When i went back to test it the next day both track are working in both directions, i guess there may have been something stuck in one of the spools or reliefs..
I also checked the Stick spool and found a large piece of metal floating in there, and swapped the relief valves but it was still creeping very fast, swapped the bucket and stick hoses around so the bucket controls move the stick and it is still creeping and the bucket is working fine so i now believe the stick cylinder is bypassing..

 

[uffex]

Good day Jamie
Attached may be of help,
Kind regards
Uffex