Kubota BH90 backhoe problem

[tvman]

Hey all, finally joined this site and I am hoping to get some advice from the experts.

A couple days ago I was using the L4330 using the loader to lift some rocks into a trailer. While dumping the last rock, the tractor started tilting to the front right.

I quickly lowered the bucket onto the trailer to stabilize the tractor. Needless to say the pucker factor was pretty high.

Anyway I assumed the right front tire had gone down and the left rear tire was at least 10" off the ground, however the tire wasn't flat. What I discovered was that the left stabilizer on the backhoe had extended on it's own.

Tried raising the stabilizer but the lever wouldn't move however it would go the opposite direction and extend the stabilizer even more.

Shut off the tractor and started tapping the valve with a hammer and finally was able to release pressure .

Question is why this valve would activate on it's own.

 

[J_J]

Usually a spool valve has centering springs, that keep the spool centered.

If part of the spring is weak or broken, the spool will let some pump flow into the cyl.

There might be some debris in the spool bore to prevent centering, such as rubber , metal, etc.

 

[tvman]

Thanks JJ, I am in the process of removing the complete valve assy. I also noticed that the boom valve is leaking on the top seal. Probably wouldn't hurt to reseal everything while it's apart. Your thoughts.

 

[J_J]

If the valve has o-rings, go ahead and replace them, but a lot of valve do not have o-rings.

 

[tvman]

If the valve has o-rings, go ahead and replace them, but a lot of valve do not have o-rings.

JJ, as a follow up. I went ahead and replaced the whole valve assy. It was pretty salty but the parts guy cut me some slack.

The cost to replace the spool assembly was over 800.00 so now I have an extra valve assembly. I took the old stabilizer valve apart and everything looked good to me except the 2 o-rings looked like they had been smashed. Nothing broken or bent however.

I think I will now order all the o-rings and wipers and repack the old valve assembly. Thanks for your help!