450C Backhoe Valves

[rufustoad]

Hi,
I am installing a thumb on my backhoe and I have "luckily" found an original backhoe control valve that I have installed inline to operate the thumb. I have put everything back together and I pressure checked the entire assembly (7 valves) to see if I have any orings leaking before I install this beast back onto the mounting plates. When I put pressure on the assy I have 1 valve that is leaking out of both ports and I believe its a full leak not like a small oring leak. The valve looks good with no scratches on the stem or in the bore that I can see. I believe this is the swing valve and I am wondering if this might be normal for this valve or if anyone knows a good way to understand why this might be leaking like this? It does have 2 re-lief valves internally but the valve next to it also appears to be the same valve and only one port is leaking on it. I cant seem to find a ton of information on this setup and was hoping someone might have experience with this setup?
I have installed this new valve directly in the center of the valve assembly and assumed that this would be acceptable as all the valve ports internally match perfectly but these 2 other valves have me boggled? No clue how to insert pics here or I would but this is an older JD backhoe valve assy.

[Jim B]

The service manual for the backhoe should have information on the valves.

One possibility is the port reliefs might be leaking. The manual should tell if there are any resealing steps for those. There is also the possibility that even though the spools and bores look good there is just enough wear between them to allow a bit of leakage.

[rufustoad]

Thanks Jim, unfortunately there is not a ton of info on this that I understand and was hoping someone on here might have a bit of experience with these valves. I have looked inside these valves and see very little wear. I believe this pressure might need to be there but would like to understand it a little better. There are no checks in the manual that I see for this.