Hydraulic lift problem - 806

We have an 806 with a front end loader. Because we use three separate hydraulic controls for various functions on the loader, my brother rigged a triple set of valves on the right fender which are supplied from the right auxiliary hydraulic ports. To use this, we put a block of wood under the outer control valve lever (located next to the seat, right side) to lock it in the "up" position so the right auxiliary hydraulic ports are always pumping fluid. This has worked for years, but now we have a problem.

Some of the time the loader will lift very slowly, or not at all until you rev the engine up to fairly high speed. Even then it lifts very slowly. Seems as if we are leaking fluid through or around some check valve or unloader valve. If you put the auxiliary valve in the "down" position (thereby driving everything in reverse) it will raise the bucket at the normal rate in both of "up" or "down" position on our triple valve.

I thought it might be the control valve itself that runs the auxiliary port, but when I switched the lines to the rear hydraulic ports, (which are controlled by the inner control valve handle) we get the same results.

I have GSS-1344 manual and a parts manual, which describes the hydraulic control system, but am not sure exactly which of the check valves or unloader valves would be the cause, nor exactly where to look (other than under the seat.)

Any suggestions on this problem would be greatly appreciated

Frank

I ran into this a couple of years ago and it just drove me nuts until we figured it out.

If it works okay with the lever in the down position and the oil flow is reversed, really don"t think the problem is with your tractor.

Check the lines that feed your loader"s control valve and make sure the pressure hose hasn"t popped out of it"s socket.

If not and the connector is in place as it should be, then the pressure hose has collapsed inside itself and is shutting off the oil flow when the lever is in the "lift" position with the oil flowing that particular direction.

Allan

To prove Allan's theory, switch the hoses around at the hydraulic remote.

If the loader now runs slow with the lever in the down position, and fine with it in the up position, the hose has collapsed.

I have already replaced the hoses from the auxiliary ports to the three-valve assembly on the fender, so I know that is not the problem.

And if the hose to the lift cylinders themselves were collapsing, I would still see the same problem no matter how I hooked things up.

The only place I can see where it could occur is in the valving somewhere on the tractor.

Frank

if you are using Pioneer tips on the hoses and coupling into the IH tips on the tractor the problem may be with the couplers. the IH couplers have a cone with a flat pin type end and the Pioneer ends use a ball. When they start to get worn the flattened tip slides off to the side of the ball when coupled and that allows the ball to partially close. That causes a restriction in one direction but the ball will be opened by hydraulic flow in the other direction. If you can push the cone with pin off to the side as you push in on it, that most likely is your problem.

Very interesting..... I'm not near the tractor right now, but will try to find out if we have a ball (Pioneer) or IH type of couplers on the tractor. I do know the hose couplers have a ball end, though. Didn't even realize there was a difference. I will let you know.

If you are useing the out side lever, check the roll pin on the linkage behind the cover in front of the seat. The pin will partially shear or work out and not open the valve fully.

All the connectors on the tractor and hoses are Pioneer (round ball), so that is not the problem.

Being that we have rerouted the hydraulics through different ports on the tractor and replaced the hoses, what else could cause the problem other than a check valve or unloader valve leaking?

(quoted from post at 00:55:43 11/09/10) All the connectors on the tractor and hoses are Pioneer (round ball), so that is not the problem.

Being that we have rerouted the hydraulics through different ports on the tractor and replaced the hoses, what else could cause the problem other than a check valve or unloader valve leaking?

Click to expand...

It is still possible that it is a coupler on the hose. If the ball travels too far it will allow the ball in the other part of the coupler to close. Swap the ends on the hoses and see if the problem now occurs in the opposite direction.

Have maybe those upper steel lines out to the couplers been replaced with hose(s) sometime in the past?

Still say that this is a restriction issue somewhere on the downstream side.

Allan

I'll be back at the ranch this weekend and will look into all the suggestions. I think I will also get a 0-3000 psi gauge and check out some pressures where I can.

Frank

I was thinking about you the other day when I was up in Scottsbluff at an auction. How are you doing?