Stabilizer stuck down

[CMV]

Lurked here for a while but now have a specific problem that I couldn't answer by searching.

I have an 83 JD 500C backhoe. It does everything it's supposed to but has lots of minor issues as one would expect on a machine that age. One of the issues is the stabilizer cylinders leak down quickly. Overnight they'll be on the ground but while just operating the machine I'm frequently pulling them back up because they've dropped about 10" or so. Anyway, yesterday I was doing some digging & they worked just fine. Then I was moving some dirt piles and I turned around to put them back up all the way. The right one (left as you're spun around to use the backhoe controls) wouldn't move up. Pull the control & nothing. So naturally, I moved it down & that worked fine. Tinkering around & it kept moving down just fine but not up at all. So I ended up with it almost all the way down lifting the right rear tire off the ground.

I'm assuming the problem is in the valve under the control levers.

How difficult a task is it to remove & replace these? The swing valve is pretty sticky as well so would be a good time to do them all assuming they aren't crazy expensive each. But if there's something else I should check first I want to do that before randomly changing parts that I think *might* be the problem.

When I pull back on the lever to raise the stabilizer nothing happens. I don't hear the engine strain like it's trying to move & can't.

 

[whis]

cylinder could be bypassing on inside

 

[Stimw]

My wild GUESS, a piece of seal broke loose inside the cylinder and is acting like a check valve and won't let the pressure back out. ????
If it is the control valve you could loosen the hose to the cylinder letting pressure off and it will lower the tire.

 

[CMV]

My wild GUESS, a piece of seal broke loose inside the cylinder and is acting like a check valve and won't let the pressure back out. ????
If it is the control valve you could loosen the hose to the cylinder letting pressure off and it will lower the tire.

I know very little about working on hydraulics so here come some dumb questions.

If I loosen up the line coming from the bottom of the valve, is there still a lot of pressure in there? Or with the motor off & it sitting overnight (or longer) is there no pressure in the hyd lines? I expect it to loose hyd oil but will it pour out or shoot out at high pressure?

After opening a line, does anything need bled like car brakes do if you open those lines? Or will it just purge whatever air I let in on its own?

 

[Stimw]

You just want to loosen a fitting, not remove it. If there is pressure it will come out with the fitting just loose.
If the outrigger is stuck down there might be pressure on the hose if the problem is in the valve.
Always be careful with hydraulics, they will squirt fluid everywhere and things will drop if the wrong line is taken apart. Normal working pressure is about 2000 psi.
It helps to have clean buckets and rags handy, you can reuse fluid if it doesn't get dirt in it.

 

[CMV]

I'm going to keep putting the opposite outrigger all the way down daily. That should push the stuck one up a little after a few days. I don't know if putting a cinder block under it will help speed that along or if the weight would just crush the block, but will find out. I want to move it enough to move the machine to a better spot to work on it. As it sits, it's all the way at the back & bottom of my property in tall weeds. Stuff tends to break in the most inconvenient places.

When I went out today on my lunch break, it settled enough to where the rear tire was back on the ground. I don't know of that's an indication of anything that might be the problem, but it seemed to leak down on its own like it normally would. I also grounded everything else - all cylinders closed except stabilizers fully open. The hoe arm & bucket are fully extended & on the ground, front bucket flat on the ground. So if I disconnect something I shouldn't, nothing should move.

I use the machine 90% of the time as a front end loader. Would there be any harm in chaining the stabilizers in the fully 'up' position? Would keep the chrome part of the cylinders out of the weather & I wouldn't have to worry about them letting themselves down as I'm doing other work. I could see forgetting and trying to let them down while chained & maybe that would break something. How do they work on newer machines? I think any backhoe will let its buckets down if left to sit long enough. Do they all drop their stabilizers too? I know they don't drop as fast as mine, but after a few days are they still fully 'up'?

 

[whis]

won't hurt to chain them up

 

[SPYDERLK]

Lurked here for a while but now have a specific problem that I couldn't answer by searching.

I have an 83 JD 500C backhoe. It does everything it's supposed to but has lots of minor issues as one would expect on a machine that age. One of the issues is the stabilizer cylinders leak down quickly. Overnight they'll be on the ground but while just operating the machine I'm frequently pulling them back up because they've dropped about 10" or so. Anyway, yesterday I was doing some digging & they worked just fine. Then I was moving some dirt piles and I turned around to put them back up all the way. The right one (left as you're spun around to use the backhoe controls) wouldn't move up. Pull the control & nothing. So naturally, I moved it down & that worked fine. Tinkering around & it kept moving down just fine but not up at all. So I ended up with it almost all the way down lifting the right rear tire off the ground.

I'm assuming the problem is in the valve under the control levers.

How difficult a task is it to remove & replace these? The swing valve is pretty sticky as well so would be a good time to do them all assuming they aren't crazy expensive each. But if there's something else I should check first I want to do that before randomly changing parts that I think *might* be the problem.

When I pull back on the lever to raise the stabilizer nothing happens. I don't hear the engine strain like it's trying to move & can't.

Check hoses, particularly the retract hose, on that cyl. One of them may have a failing/collapsing inner liner and acting like a check valve. ... Im puzzled at "no engine strain" tho. :confused3:

 

[CMV]

I've filled out several online forms for part quotes but so far only FP Smith has responded. $400+ for a new valve. You wouldn't think something that small would cost so much....

Any ideas of where else to look for parts? When I google the part number for that valve and the swing valve all I get are places to request a quote - nothing that shows inventory in stock and a price. Tried ebay & CL with no luck also. There's got to be some places with used inventory for this sort of stuff.

 

[whis]

before I thru parts at it I would check pressure on all the valves