Loader Valve

[jgbanshee]

I have a Cross 2-spool valve with power beyond that I fit to my tractor loader. When I raise the loader up into the air all the way the valve makes a squeal noise and I could feel it in the joystick. Why is this? The original valve (w/o PB) just made the noise of the engine going under load. What might be the problem?

 

[Farmerford]

If your loader valve has a pressure relief valve set lower than the system relief it is probably the loader valve relief valve opening to bypass hydraulic fluid when the loader cylinders extend fully and fluid can no longer flow into them.

 

[kennyd]

I agree with FF, it sound like the relief valve.

 

[jgbanshee]

I only have two reliefs in my system. One in the loader valve and one in the backhoe valve. The loader relief is set at 2400 PSI and the backhoe was preset at 2550 PSI. The backhoe relief is not adjustable. Should the loader relief be set higher?

 

[RonMar]

You changed valves, what are the GPM flow specs of the two valves? If the old valve was rated for a larger GPM, the safety in it may have been quieter as it was flowing less fluid to maintain pressure. If it is the safety making the noise, it should also make the same noise when you fully extend/retract the bucket dump cylinders and open the safety that way.

You said you put in the new valve with PB? How is it plummed compared to the old vlave without PB? So you are running a line somewhere from the PB port on the new valve, and the return line used on the original valve is plummed to the new valves return port?

 

[jgbanshee]

I am not sure of the flow rating for the oringal valve but according to the specs on the machine the flow is 26GPM. The new valve is rated for 30 GPM. The noise only happened when the lift cylinders were fully extended.

I have the Pump>>IN>>OUT>>Reservoir, PB>>IN>>OUT>>Reservoir

 

[RonMar]

I am not sure of the flow rating for the oringal valve but according to the specs on the machine the flow is 26GPM. The new valve is rated for 30 GPM. The noise only happened when the lift cylinders were fully extended.

I have the Pump>>IN>>OUT>>Reservoir, PB>>IN>>OUT>>Reservoir

Interesting... If it is the safety making noise, it should do it any time you continue to hold the valve with the cylinders fully extended(loader full up/full down, bucket full dump/full rollback) or when you try and exceed the loaders lift capacity.

I don't quite understand the last sentance. You should come from the pump to the valve "inlet" port. The work ports of course go to/from the cylinders. The Return port should have an unrestricted low pressure path back to the resovoir with the only possible restriction on the line being a return line filter. The PB port should go to the next valve's "in" port.

 

[john_bud]

I only have two reliefs in my system. One in the loader valve and one in the backhoe valve. The loader relief is set at 2400 PSI and the backhoe was preset at 2550 PSI. The backhoe relief is not adjustable. Should the loader relief be set higher?

The backhoe relief will never (or seldom) ever operate. Why? In order to reach the 2550 at the BH, the pressure at the other end of the supply (PB) line has to be about 2600-2650 to allow for line loss. For a balanced system you should probably put the loader relief at 2650-2700 psi.

You do need to be aware of what that will do to the rest of the system. If possible - find out the real system pressure that Ford set them too. The dealer should be able help - assuming they have a good mech on duty.


The change in settings will not affect the sound. It's the relief operating. Different ones have different sounds. No biggie. After what you've been thru hearing it must be a sweet sound to your ears!
jb