Hydraulic Rear 3-point blade

[duckngooser]

I recently purchased a 10' all hydraulic rear blade. It's used... When moving with the blade angled, it appears the hydraulic cylinder gives slowly letting the blade turn with the dirt.

Is this normal operation? Or could the cylinder be wearing out?

When I hit the control for the cylinder, I can move it back to where it was...till it starts moving again and slowly creeping back.

Thanks

 

[J_J]

Cyl appears to be leaking.

Install a hyd gage and check pressure.

Install a gate valve in the circuit, and when you set it, turn the gate valve off. If the cyl moves, the cyl is bypassing.

A good valve should lock the cyl in the last position.

Valve could also be leaking. If there is enough force on the blade, and the valve spools are worn, then the cyl could force fluid past the spool lands.

 

[MtnViewRanch]

Set the blade as you want it. Assuming that you have quick disconnects, disconnect the hoses and see if the cylinder moves. No money spent. :thumbsup: My bet is that it is the valve and not the cylinder, but then again it could be both.

Good luck and let us know how it works out.

 

[J_J]

How old is the tractor and valves you are using?

I would guess the ratio of cyl leakage to valve leakage is about 80/20, may be 90/10.

Hyd valves only see flow and pressure, whereby cyl see that plus other external forces.

 

[duckngooser]

The tractor is a massey 3660. So early 90's. I have a tb100. I might hook it on and see if it has the same issues. But first I'll try setting it and unhooking the hydraulic hoses.

When you say cylinder leakage, are you talking internal leakage? Or should I be noticing hydraulic oil leaking out of the cylinder while pulling the blade against some dirt?

Thanks for your replys.

 

[MtnViewRanch]

The tractor is a massey 3660. So early 90's. I have a tb100. I might hook it on and see if it has the same issues. But first I'll try setting it and unhooking the hydraulic hoses.

When you say cylinder leakage, are you talking internal leakage? Or should I be noticing hydraulic oil leaking out of the cylinder while pulling the blade against some dirt?

Thanks for your replys.

Both, the leak can be on the piston seals and or the cylinder seals.

JJ, agree with you as far as the cylinder taking the beating, but from what I have seen, the spool valves on these AG type tractors are not all that good and from what I have seen are the culprit a lot of the time.

 

[Chilly807]

It's also possible there's a bypass relief valve between the two sides of the cylinder, so that when blade force becomes excessive it dumps fluid from one side of the piston to the other. If the induced pressure from working the blade is too high, or the valve is set too low, it will relieve the pressure on the "high" side to the low side, causing the blade to move.

Check the hoses coming from the cylinder in question, if they come together at a small block before going to the tractor remote QC's there's a good chance you have one of these valves.

Sean

 

[duckngooser]

It was the tractor hydraulic controller. I switched the line to a different controller and had no issues.. Now I need to investigate the valve on my tractor...

Thanks for all your replies!