wood chipper hydraulics help

[davedj1]

I have a friend that has an older Badger wood chipper, the in feed rollers suddenly stopped having any power to turn them, they turn real slow and stop easily. He, without my involvement, went and got a new pump and, what I believe to be, a flow divider with relief valve to power the two hydraulic motors that turn the in feed rollers. He put them in and still has the same issue.
I am thinking first off we should put a pressure gauge coming out of the control valve(runs the rollers forward and back) going to the motors.
Secondly is it possible that one of the motors went bad and the other one was doing all the work and now that one just went bad?
I'm assuming the new pump is doing it's job so it has to be something downstream
Could the control valve need to be rebuilt?
Any help and/or advice greatly appreciated.
thanks,
dave

 

[J_J]

If you install a hyd gage in the valve, and put a load on the motors, you will see the presure developed by the load. You can isolate the motors to check each one.

If they are 3000 psi motors and you put max load on them, the gage should read about 3000 psi or whatever the relief valve is set.

 

[davedj1]

Thanks JJ, I knew you would be along to help.
What are the chances of the directional control valve leaking by?
I believe (after some searching) the new block valve is a priority flow divider as it does have some sort of relief in it.

 

[J_J]

If your valve is an open center valve, fluid will be flowing through the valve all the time.

The purpose of the spools is to redirect the fluid to wherever.

The spools are a precision fit and if they leak, that means that they are probably worn.

If the relief valve should happen to be stuck open, it can bleed you fluid to tank.

You can test all of this. using a hyd gage.

Is there a feed trigger for the rollers , or are they running all the time the engine is running.

Some flow dividers have a primary circuit in that it will have the same flow all the time, and the other circuit will have what is left over from the source.

So in a situation like that, say you have 10 GPM's, and the primary gets 5 GPM's that leaves 5 for the other circuit.

If your engine is running less than max, the other circuit may only hace 2 to 3 GPM's, but even at that, the hyd motors should run.

First check your flow in GPM's.

Check the pressure.

If your pump is weak there may not be enough fluid for the hyd motors for the rollers.

If you put a gage in a tee at the IN port of the valve, you will see the pressure from any hyd work being done..