Outrigger slowly creeps down

Alan7s · Feb 13, 2016

One outrigger on my LBH won't stay up. Takes a few days but it creeps down, and quicker when in use.
No leaks anywhere but I rebuilt the cylinder anyway. Seals were all fine and inside cyl smooth.
Back together, no change. So I thought it must be the control valve, but the hyd shop guy said
probably not. Other side is fine. Any ideas? By the way it's a Terramite T5C. Thanks

T_e_r_r_y · Feb 13, 2016

If not too much trouble, I would move the creeping outrigger cylinder to the other side. Just to see if it is the cylinder or not.
By the slow creeping down of the cylinder, air or fluid is starting to get by the seals.
I don't mean to sound callous, but did you actually check the valve yourself? Everything tight ,no cracks, levers move easily, both ways, dothey return to center by themselves.
Is there a schematic for the hydraulic system?
Could a seal have gotten worn, ruptured or torn?
Spring getting weak and not returning valve to center position?

T.J.

txdon · Feb 13, 2016

The outriggers on my BH90 Kubota also leak down - from day 1 - it's considered normal and I keep them tied together when not in use. Your machine might be different but it might also be normal.

4570Man · Feb 13, 2016

I keep a ratchet strap across the outriggers when not in operation to prevent them from leaking down.

Alan7s · Feb 13, 2016

4570Man said:
I keep a ratchet strap across the outriggers when not in operation to prevent them from leaking down.

Thanks to all for replies. TJ great idea to change the sides. The levers on the valves have good spring, return to center OK. I do have a
good schematic for the hydraulic system. I have not opened the valve to inspect; wasn't sure that was within my abilities, but having rebuilt
all the cylinders without problems, maybe I could do it. Is it possible to remove a single valve, or does the whole assembly need to come apart?

When you refer to a seal getting worn or torn, I assume there are similar seals in the valves that control the cylinders and you are referring to those?
On the other hand, if it's normal, don't want to create problems. Just concerned by the slow "let-down" on only one side while digging.

Thanks again

sea2summit · Feb 13, 2016

4570Man said:
I keep a ratchet strap across the outriggers when not in operation to prevent them from leaking down.

That^^

4570Man · Feb 13, 2016

If you lift up the back wheels of the tractor with the stabilizers does it leak down a noticeable amount in like 30 minutes? Leak down is normal on all hydraulics, but it sounds like it is happening pretty fast. My stabilizers leak down a couple inches over a couple weeks. I don't notice any leak down while in operation.

Alan7s · Feb 13, 2016

4570Man said:
If you lift up the back wheels of the tractor with the stabilizers does it leak down a noticeable amount in like 30 minutes? Leak down is normal on all hydraulics, but it sounds like it is happening pretty fast. My stabilizers leak down a couple inches over a couple weeks. I don't notice any leak down while in operation.

If it was only a matter of tying it in the up position while parked it would be no problem. But while the outriggers are in use during digging,
the tractor begins to tilt which is a constant reminder (every couple minutes) to hit the lever to raise it back up again. That seems too fast,
especially when the other side will not go down an inch in a month.

4570Man · Feb 13, 2016

There is definitely something wrong. They shouldn't leak a notable amount in the time spent digging.

IceStationZebra · Feb 14, 2016

Normally outriggers have a counterbalance valve, which is the most likely cause. Spool valves do not have positive seals and will always have some leakage. And assuming you have good CB valves, you could leave the seals out of the cylinder and it would only droop a little due to differential area. ISZ

Alan7s · Feb 14, 2016

IceStationZebra said:
Normally outriggers have a counterbalance valve, which is the most likely cause. Spool valves do not have positive seals and will always have some leakage. And assuming you have good CB valves, you could leave the seals out of the cylinder and it would only droop a little due to differential area. ISZ

Any way to check to see if the unit has counter balance valves, i.e., anything physical that one would look for?

oldnslo · Feb 14, 2016

Look at the cap end of the cylinder. Is there any hex shaped caps that don't look like bolt heads? If yes this could be the valve. There could also be a a body in-line mounted close to the cylinder. These could be counterbalance valves or a pilot operated check valve.

IceStationZebra · Feb 15, 2016

I found a parts book online and it did not show any counterbalance or PO checks at all, but the hydraulic diagrams were not very good. They would most likely be cartridge valves screwed into a block. ISZ

Alan7s · Feb 15, 2016

Soon as we get some temps above freezing, I'll switch the cylinders and see, although I'm almost positive they're OK. Looked fine when taken apart,
and all new seals made no diff at all. So if it uses cartridge valves as ISZ suggested, is that possible next cause, and can those be serviced individually?
Finally getting this fine machine with zero fluid leaks - external that is.

IceStationZebra · Feb 15, 2016

Counterbalance valves have O-rings but I believe the main sealing surface is steel-on-steel. They can also be replaced, just have to match up the cavity. But if there is no CB then you are looking at excessive spool valve leakage.

The other idea you can try is to switch the cylinders side to side (or swap hoses at the control valve) and see if the problem stays with the cylinder or the valve. And remember you have to work the air out of the cylinder.

ISZ

Alan7s · Feb 16, 2016

IceStationZebra said:
Counterbalance valves have O-rings but I believe the main sealing surface is steel-on-steel. They can also be replaced, just have to match up the cavity. But if there is no CB then you are looking at excessive spool valve leakage.

The other idea you can try is to switch the cylinders side to side (or swap hoses at the control valve) and see if the problem stays with the cylinder or the valve. And remember you have to work the air out of the cylinder.

ISZ

On my machine, there is one large block of valves with all the controls on that. A large line comes from the pump to that, and then the small lines
go to the cylinders; nothing in between. However, on this valve block, there are what look like other valves next to the ones worked by the control
handles. Could these be some sort of check valves?

Yes, even better idea to switch the hoses if I can get at them.

oldnslo · Feb 16, 2016

follow the hoses (if possible) from the cylinder to the valve bank. If there are any valves in these lines there is a good chance that they are the load holding device. Both hoses may connect to the same block.