BH75 More problems..

[grizzjeeper]

Well put the backhoe on last night, havent used it since last october. All controls work good except left stick lowering boom. It will move about half way then there is a major resistance. Boom does lower and is under pressure, just slow, like its not fully opening up. Pulled cover away from valve area and the little rod that goes into that housing doesnt go as far as the others. Up movement is fine. This back hoe has 12 hours on it. Already broken the cylender, twisted the dipperstick arm (there was a shim missing from the factory that contributed to that) and now this. Its out of warrenty and every time I want to use it it either breaks or its broken.

I was looking at ways to get the cap off the valve on the bottom but they way its put in there is like a chinese puzzle, very poor design for someone who needs to work on it. Any one have any ideas of whats wrong? I have tried the usual of purging the lines by holding the boom in the up position etc.

What next?

 

[dfkrug]

I was helping a guy in Feb who had a fairly new BH75 and his
problem was that the joystick swivel eyes in the linkages needed
lubrication. That may be it for your boom control.

 

[grizzjeeper]

No its in the valve somewhere, the linkage is fine, you can see the cylinder drop into the valve boddy and stop.

 

[dfkrug]

Looks like you will have to take out your valve stack then. I am
not personally familiar with the Kubota valve stack but based on
others I have assembled/disassembled, you will have to remove
all hoses, then take it out of the hoe console. Then you will have
4 threaded rods that hold everything together. Remove those and
the stack comes apart.

Before you do that, try this experiment: remove the 2 hoses at the
boom cylinder. This might not be easy if the upper one is shrouded
by the main boom itself. In that case remove it at the valve and
place a spare hose on the valve fitting. Run the tractor (slow) and
operate the culprit valve with the hoses in a clean bkt. If the
valve works OK (we hope), your cylinder is the problem.

Sorry to hear of all your problems with this hoe.

 

[mazurrj]

This has happend to me a number of times, lucky it was only nuts on linkage coming loose and plunger not compressing all the way because of play in the bolts. Sounds like you might have already checked that though. but make sure the nuts on all the bolts in the linkage for stack valve are tight and snug with no play.

 

[dfkrug]

I have also seen the linkages get messed up in shipping. If
the alignment of the joystick is not just right (and lubricated)
the valve feels like it is sticking.

 

[wushaw]

This has happend to me a number of times, lucky it was only nuts on linkage coming loose and plunger not compressing all the way because of play in the bolts. Sounds like you might have already checked that though. but make sure the nuts on all the bolts in the linkage for stack valve are tight and snug with no play.

I had this problem also with mine and fixed it with good NAS hardware that works and I have no more problems. I did have to ream the holes up to 1/4" for the standard hardware to fit.

 

[grizzjeeper]

Well, fixed but dont know how.. I pulled the bottom cap from valve assembly on the plunger in question. looked to see if the bolt had vibrated loose. Spring was there, nothing there. put it back together now everything works fine..??

Anyway thanks for your help guys.