734B control valve

[oracle_of_ferndale]

Control valve on 743B is leaking. I can see (with a borescope) that it is not leaking from any of the line connections. Where might it be leaking from? Are there seals in the control valve that could fail and cause a leak? Not looking forward to removing / reinstalling this part again. Need to get it right this time. Appreciate any suggestions.

 

[SkidRoe]

It sounds like the spool seals have failed, not an uncommon occurrence. Replacing them is not a horrible job, once the cab is flipped up. The seal kit is available form Bobcat, and is pretty reasonably priced.
HTH - SR

 

[oracle_of_ferndale]

It sounds like the spool seals have failed, not an uncommon occurrence. Replacing them is not a horrible job, once the cab is flipped up. The seal kit is available form Bobcat, and is pretty reasonably priced.
HTH - SR

Thanks SR. I found the 3-page dissertation on topic started by billrbg - very helpful. Unfortunately, I had already removed the control valve while the site was down. I ordered the seals and will replace them when they arrive. Can anyone tell me if a shop would be able to test the control valve before I reinstall it? Thanks.

 

[Tazza]

Thanks SR. I found the 3-page dissertation on topic started by billrbg - very helpful. Unfortunately, I had already removed the control valve while the site was down. I ordered the seals and will replace them when they arrive. Can anyone tell me if a shop would be able to test the control valve before I reinstall it? Thanks.

I guess a shop could do it, but they would charge you....
Just be careful doing it, when you slide the spools back in, rotate them and make sure it's all oiled up. The spool does have sharp edges, you don't want to cut the seals up.
Many people have re-sealed a control block without needing it to be tested afterwards, hopefully your repair will go smoothly and it will be leak free.