Backhoe Problem with BH4560 backhoe hydraulics

rossibob · May 23, 2005

Well, I got out on the tractor on Sun. The backhoe was working very well to start. After about an hour I noticed that I had fluid coming from the two swing arm cylinders that I had just rebuilt. It may only be coming from one and just crossing over to the other through the hose that runs between them. ??? Soon after i noticed that the main lift for the backhoe kept sagging. I would have to keep pressure on the lift handle to keep it up. If I wanted to move the tractor, I had to put the transport locking pin in to keep it from dropping to the ground. I don't know if the problem is in the valve or in the cylinder. Any thoughts??? Rossi Bob

GaryE · May 25, 2005

Bob,

If the swing pistons are leaking, something did not get sealed properly. You may also have a valve problem, but what you are describing is a leakycylinder.

I think you need to look at those pistons again. Make sure the seals and orings did not get damaged during installation. And make sure there is no dirt inside.

Good luck.

Gary
On the beach in Ft. Lauderdale! /forums/images/graemlins/crazy.gif

rossibob · May 25, 2005

Thanks for the reply. I will pull down the cylinders and see whats up with them. Concerning the second problem with the lift arm not holding, I am leaning towards the fact that I might have a valve that is sticking or needs to be replaced up near the controls. /forums/images/graemlins/confused.gif

GaryE · May 25, 2005

Bob,

It is a real possibility you have a valve problem, but it could also be a seal problem. It maybe bypassing internally. I think since the swing pistons were leaking, it is possible the others might be also. That is the case with mine. I am not sure there is an easy test for checking a valve versus the piston, maybe others can offer some suggestions, but once you get the hang of it, resealing the pistions really is a easy task. /forums/images/graemlins/smile.gif

Gary.....

Only 15 days till I can leave the beach /forums/images/graemlins/confused.gif

rossibob · May 28, 2005

Went out just to try the backhoe today. It worked great for about 45 minutes. Then the boom started to sag on me again. From this I surmise that my problem is a cylinder seal. I would guess that when the seals get hot, they don't hold the fluid properly. Does anyone agree??? Thanks

GaryE · May 28, 2005

Not to mention the fluid will also thin out a bit when hot. I think it is reseal time. I plan on doing the rest of mine wether they need it ir not when I get back home.

Good luck,

Gary

Still on the beach /forums/images/graemlins/frown.gif

bugstruck · May 29, 2005

My take is to stop the cylinder leaks first. Hard to blame a boom drop on a valve, when a hydraulic circuit is bleeding. Once the blood stops, then maybe the valve can be considered as the culprit, not sooner. At least not in my limited world. /forums/images/graemlins/grin.gif

rossibob · May 29, 2005

Thanks guys!!! The seals are on order. Bummer Monday is a holiday. I guess I will have to find some other work to do. I better not say that to loud my wife is near by and I'm sure she could find some not so fun work for me to do. /forums/images/graemlins/grin.gifOff to the great outdoors and away from the laundry room and kitchen if you know what I mean. /forums/images/graemlins/wink.gif

rossibob · Jun 7, 2005

Well, I got the new cylinder kit in and got it mounted. Today I got out and had a great time digging stumps. Once again, after about an hour the boom started to slowly drop. Now I must asume the problem is in the control valve. They know me by first name at my Kubota dealer parts counter. I must say that they like the fact I come in knowing the all the part numbers I need. My wife says that she is now a tractor widow. /forums/images/graemlins/smirk.gif

KubotaTrax · Jun 8, 2005

The arm control valve has a check ball to keep pressure on the cylinder when the valve in neutral. Locate the valve in question and in the front of the valve it will have a port that looks like it is plugged. Take the plug out and be careful not to drop the spring that holds the check ball in place. You may find you have a weak spring or trash in the seal area.
Did this make any cents /forums/images/graemlins/confused.gif?? hehe. My mind is weak but my back is strong.
Hope this helps.
/forums/images/graemlins/smile.gif