Loader Control Problem

[RDrancher]

Can you install a gauge in the curl or uncurl hose to see if you are getting any pressure at that point. If it sounds like you are going over relief it would point towards the flow path is being restricted or blocked in the curl / tilt function.

You bring up an interesting point. I have to wonder what happened to the missing second detent ball. Did we lose it when we took apart the valve...or since the piston overtraveled past the balls...is it stuck in there some where? It seems suspicious that the cylinders would act up at the same time that the valve did.

 

[RDrancher]

I'll add one more thing to the mix.

The overtravel to the joystick started after my former employee ran the tractor for a few days. My wife was delivering my lunch and noticed him "yanking on" the joystick "like a gorilla." He broke two 3pt sway arms and several other things over the course of a couple months, so I had to let him go.

Is it possible that the detent ball fractured? I know that a complete ball won't fit through the valve opening because I accidently dropped one in there while I was putting it back together.

 

[J_J]

In order for the valve to go into bypass, pressure is being developed somewhere, either in the QD's or the cyl.

If it were the cyl, the shaft would be trying to move.

Did you shift the hoses from the lift to the curl?

If the load checks are acting up, you will get some weird situations.

As I said many times, use a hyd gage to monitor and help trouble shoot the hyd system.

Did someone remove the spool from the valve and inspect, clean?

Did they hook the valve up and test it?

If not, you should have not paid anything.

 

[RDrancher]

JJ, I haven't done any checks other than trying to get it to work on the job. I finished today, so I have the long weekend to try to figure it out. I'll try to explain better what's happening.

Bucket in the air from 1/4" off the ground up to mid-height+ and it will un-curl. I think the weight of the bucket is assisting.

Bucket flat on the ground, or bucket curled all the way back at full loader arm height
Move the joystick to the right and nothing happens - Sounds like if you were to hold the bucket in curl with the cylinders collapsed all the way (bypass?)

Try to use the bucket cutting edge to pull back a loose pile - Bucket flops over the pile like when there is no pressure.

The joystick "overtravel" went from being an annoyance to not working at all in just a couple of days. As I explained before, the cup on the bottom of the valve that limits piston travel had loosened up. I'm an operator not a hydraulics guy, so any help you can give will be greatly appreciated!

 

[J_J]

Do you know what valve you have such as manufacturer, and model number.

Did the float and detent work like they should from new?

If the valve has regen, it only works when the lever is moved.

You should be able to lock the bucket at any angle and then use float or presure down to back drag.

There could be parts missing.

The curl part of the valve is inside the spool, and the spring centering section and float is outside the spool.

If someone has been swapping parts, it would be hard to come up with answers.

Do you happen to have a manual on the valve?

Does your valve look like the one that jinman posted

 

[RDrancher]

I appreciated the response JJ.

The valve is the exact one jinman posted.

Float and detent worked fine when new. In fact, all loader / bucket functions worked fine until the joystick / spool over traveled a couple of days ago.

I don't use float, but using anything more than bucket weight pressure down to back drag and the bucket will try to curl.

The only thing missing when I took it apart (looking at jinman's photo) was one detent ball. That could have gone missing when Ii took it apart on the tailgate of the truck.

No parts have been swapped. I helped the service manager at my dealer put it back together with a new ball to replace the missing one. We removed the cap on the loader lift side just to check and both look the same. My service department had never had this particular valve apart since they'd never had a problem with one. I didn't leave it there to be thoroughly checked since I needed to get back on the job.

Sorry, no manual. All of the manuals for everything I own were stolen in a briefcase out of my truck.

I used the bucket to move gravel yesterday and today. I have to angle the bucket down a little going into the pile, or it curls right up by itself. I figured it would get better, but it didn't. Maybe jinman will read this and point me to the suction hose.

 

[J_J]

Look in the hyd tank to verify any air bubbles.

Can you remove the lever or cables from the valve and push and pull the spool.

When you push the lever to the right, can you see the spool move?

It should move in and out about 1/2 to 3/4 in.

 

[jinman]

Maybe jinman will read this and point me to the suction hose.

John, I'm not sure what you mean by "suction hose" in reference to your loader. Either hose to the bucket can be pressure or suction depending on whether you are curling or dumping. Do you mean which hose has pressure when you are backdragging and holding the bucket lip down with pressure against the pile (joystick to the right)? I don't know what the color code is for the dust covers. I just hand trace the lines when troubleshooting.

 

[J_J]

I may have suggested that the suction hose might be the source of the air in the hyd system.

 

[jinman]

I may have suggested that the suction hose might be the source of the air in the hyd system.

The main line does have a suction pipe that can draw air at the filter or a "T" going to the HST transmission, but I think John's lift function works normally for his FEL. I also believe his 3PH works normally because he hasn't mentioned that as a problem. It just sounds to me like his loader control spool is not sealing properly or he might have a cylinder leak. With the evidence of his having a helper who was abusive to the joystick, there may just be internal damage in the valve.