Loader Valve Test Port Location

[Thumbs Up Farm]

J-J
I assume by QD you mean Quick Disconnect? If so, there are none in this system. The loader boom will drop quickly without loading the pump if I push the lever all the way forward, into the boom float position, which is what I have been doing. When I do controlled/slow lower it loads the pump, not dead head, but definitely forcing fluid through the relief.

I believe the bucket curl is caused by leaking spool seal o-ring. I already have the kit for repair.

Not sure if I can activate the relief with the curl circuit. I will have to try that.

As to the other options of replacing the valve, I have certainly considered that, and looked at several options. That will be my last resort as I will have considerable cost and fabrication to get the tank return, which now dumps directly through the valve square area, into the built in tank.

I am willing to risk some time and price of a few O-rings to try and save this valve. Besides, I am gaining a lot of knowledge in the process.

 

[J_J]

Just using the loader lift, should not cause the relief to activate unless the bucket is over loaded.

You might try removing the cyl pins from the lift cyl and see if the cyls act normally, gong into relief at the specified pressure.

I would suggest to install a hyd gage and check the relief setting.

It will let you monitor and trouble shoot the hyd system.

If the relief is low, just raising about a half load might cause the relief valve to open. Relief valve might need cleaning.

In general, if the relief valve will activate at the specified pressure, that is a good indication of the hyd systems health.

 

[Thumbs Up Farm]

The lift control ONLY causes the relief to activate when it is being lowered. No problem lifting loads. No strain whatsoever. This thing has enough power to stand the tractor on its nose while lifting, even with rear tires full of methynol and extra weight added to the rear. But, when I lower the lift it cause the pump/engine to load.

The loader control has a float position, with no down pressure, when the control lever is pushed all the way forward. In this position, the pump/engine is not loaded when lowering. It would seem that hydraulic DOWN pressure is somehow meeting against a blockage, either in the form of opposing pressure in the spool, a relief valve being stuck, or something else ?? Referring to the picture again, the spool #3 is the loader spool. Can you speculate as to what the issue may be with the valve in this circuit?

I definitely need to check the relief setting. Do you think the other plug 74? (rear one, beside loader spool) is the one I should use to check relief pressure? I will need to move the lever bracket over to gain access to that plug but should not be a problem. I will also see if I can get the curl circuit to activate the relief valve this afternoon.

Thanks again for you help, at least I am learning a few things.

 

[J_J]

Did you switch curl and lift hoses to see if the problem switched?

You could even switch A work hose port to B work port hose.

Do you have a hyd gage n the hyd system?

If so, what is the pressure when lowering, and at what point does the relief valve activate?

You should have an open path from the rod side cyl port to tank.

Can you raise the loader arms and then tilt the bucket full down.

Now, lower the arms all the way and see if you can lift the front wheels off the ground.

You don't normally see a test port for each spool, but try any of the plugs for pressure.

If there is a spring and ball under the plug, don't use it for testing.

 

[Thumbs Up Farm]

Thanks J_J for the questions here are the answers;

No,I haven't switched the hoses. I will see if I can do that. May be issues with hoses, lines, fittings, etc. But that will definetly narrow the problem to the valve
No, I don't have a gage in the system anywhere. Don't even have a gage right now, ordered one a few days ago should be in any day.
Yes, I can raise the loader arms and tilt bucket full down. Been doing this all week loading gravel on a dump truck
Yes, I can lower the arms and lift the front wheels off the ground. Although on the way down, the engine pump will be loaded.

Thanks again,

 

[wdchyd]

A bucket that will not hold probably has some bad seals..

more than likely in your cyl (s).....as mentioned above, replacing seals in valve will not fix the problem of creep-down (if it is indeed your trouble)

 

[Thumbs Up Farm]

OK, just got back from experimenting with tractor/loader. These are questions/issues that J-J pointed out.

Here is what I learned:

1.)The auto level feature of this valve works!! Wish I had known that when I was stacking round bales:ashamed: Useful feature of this valve that I didn't even know it had.:thumbsup:
2.)The bucket curl WILL cause the relief valve to work when moved to either maximum position.
3.)I switched the hoses on the valve from lift to bucket and vice versa. The problem(s) followed the spools not the cylinders. Meaning that the lift now bleeds down instead of the bucket, and the bucket now causes the engine/pump to load in one direction instead of the lift.
4.) The engine/pump loading is less severe at lower RPMs and/or slower cylinder movement speed.

So,

Is the bleed-down caused by worn o-ring on that particular spool?
What about the engine/pump loading issue, incorrect relief, bad seals/o-rings, springs, trash?????

 

[wdchyd]

Is the bleed-down caused by worn o-ring on that particular spool?

No.....This has been said before here......If you have wear creep/down on a spool then you NEED a new valve

The orings only keep the oil from dribbling to the ground, if the valve is not holding a load due to wear/tear then your clearances between the valve spool and cast iron housing are excessive....Time for a new valve.

Not everything is fixed with just an oring

 

[J_J]

Your valve has a lot more parts than a regular valve, so if you are going to take it a part and inspect ,clean, replace parts, make a video so you can put everything back together again.

Check out the load checks. They sometimes cause weird troubles.

To replace that valve, is probably big bucks. Just ask your dealer what a replacement would cost.

 

[Thumbs Up Farm]

OK, thanks guys.

I guess I was hoping for the best with the valve O-rings, cleaning, reconditioning. I did notice that the pump loading issue seemed to be better after my expermintations, maybe using the auto level feature, that hadn't been used as long as I have had the tractor at least, dislodged a stuck relief or something.

The bleed down is not too severe at this time and I have been living with it for as long as I have had the tractor. I have talked to the dealer about this before. I don't recall the costs, but it was excessive. I had already looked at replacing this valve with a joystick type valve. Prince makes one that would work in this system for around $300-$350. I will have to fabricate mounting and the tank return port connection since this valve dumps directly back into the tank through the mount and the prince one does not.

Any thoughts on joystick replacement valve(s)?

For now, I am just going to install the PB fittings (once I determine the pressure), clean it up, put in the O-rings I have(which can be done in place looking at Big deans info), since it does leak a little, and continue on my merry way. If the valve issues become unbearable, then I will probably replace the whole thing with the Prince joystick valve.