Finding point of failure - diverter valve or FEL control valve

[Bob Rooks]

I had a LW-6 Chinese backhoe that I tried using synthetic hydraulic oil in. The oil actually turned black and literally dissolved the seals, but not totally. There was still some black goo around the pistons, and the nylon wiper rings were still there.

 

[ljplum12]

That's odd. Were they damaged and your buddy just took the seals off for the picture?

I have never seen a cylinder completely missing the seals. If a seal started to deteriorate and come apart in chunks, I would have thought you would have had issues long before the seal was completely gone. Plugging up small passages in the valve and quick couplers. So gotta wonder where all that seal material is now floating around in the hydraulics, or if the filter caught it?

I've done a flush and changed the filter, so hopefully if there was any debris it's gone now.

 

[ljplum12]

I've got another update and another issue. The second piston was about as bad as the first, the seals were completely gone. Someone on here's advice helped a lot in removing the gland nut, and this time I used a pipe wrench but didn't remove the cylinder first. It came off much easier. I went ahead and ordered all new pistons and glands with the seals all installed. That unfortunately cost me $100/cylinder instead of $40/cylinder, but I didn't have to worry about messing up the seals trying to put them in.

When I got it all back together, I still have no lift. Bucket curl works. Since I have faith that it's not the cylinders at this point, so I swapped the line for lift and bucket curl on the spool valve. With the lines swapped, the lift works, and the curl doesn't. So, it's gotta be the spool! I took it apart again to see if I could determine the issue, and everything looks fine to my untrained eye. My question is, if I'm looking for the failure mechanism in a spool valve, what am I looking for? As far as I can tell there are no seals or o-rings in the spool itself that could go bad. I checked all the various plugs and ports to see if anything was clogged and see nothing.

 

[Bavarian]

Pull the spool from the section that works. Compare both very close.
MAYBE somebody played around before you and put things together backwards.

 

[freetrapper]

Just a thought have you called Koyker Mfg. and talked to them? When I had problems with my loader and though it was the spool valve I called them talked to their parts and service people they told me what the problem was and sent me the parts I needed. Their number is 1 800 456 1107 give them a call.

 

[ljplum12]

I've called and e-mailed Koyker a few times now and haven't gotten through or gotten responses from their actual service department.

Pull the spool from the section that works. Compare both very close.
MAYBE somebody played around before you and put things together backwards.

It's possible I put things back together incorrectly. This spool has a float position on it and the second one doesn't, so I can't really compare directly. I have the mechanical drawing for the valve, and based on it I think everything is right. If it's not right, I can't tell just by looking at it.

 

[Bavarian]

Did you solve the problem?

Now we know that the spools can't be switched. But I thought maybe somebody turned parts around and put left to right, front to back.