LA402 Valve problem

[LDB]

I recently purchased a 2003 B7800 with a LA402 FEL; and 600 hrs on it. I have an intermittent problem with the loader control valve. When I got the tractor everything worked fine. The tractor is in a storage facility in northern WI, and I was up there last week to move some snow and the valve would not move into the "bucket dump" position.

After some "not so gentle persuasion" everything worked fine. I worked it fir about 6 hours; left it sit outside overnight ( around 5 F) started it the next morning and everything was good.

Was the spool just stuck or do I have a bigger problem?

 

[Bulldog]

It wouldn't surprise me that you have some moisture in the lower part of the control valve. Some are bad about this. It's usually as simple as removing the lower caps from the valve and then a good clean up and lube job. Just be careful when you take them off and pay close attention how everything comes apart. Lots of small parts can fall out but it's not a hard job to tackle.

 

[SpudHauler]

BullDog, by good lube do you mean with hydraulic fluid? Because I've seen lots of seals and o-rings shrivel up and de-form when sprayed with WD and other lubricants. Costly and time consuming error to fix when that happens.

 

[Bulldog]

When my brother and I did his loader we used penetrating spray grease. His was rusted up some so we used Kroil on it first to help break the rust loose ans then we used the grease. If you are curious of the brand it was Zep 2000 penetrating grease. The only trouble after that was it was so slick that the float would stay locked any longer. If you wanted to float the bucket it had to be held in by hand.

 

[LDB]

Where can I get a diagram and parts breakdown for this valve? I have the operators manual, but it does not list parts or have any diagrams. I also have the parts manual for the tractor, but it does not list the loader parts.

 

[Babyfat]

do you have a 3 spool ( caps different length) or a 4 spool (caps same length)?

 

[LDB]

The tractor is about 400 miles north of me at the moment; but from memory, there are 2 "double acting" spools. The spool on the left (viewed from the operators position) raises and lowers the loader. The one on the right, loads and dumps the bucket. The operators manual lists it as:

Control Valve > 4 position control valve type > one detent float position; two stage bucket dump; power beyond circuit.

If it helps, only one speed for "bucket dump" appears to be working.

Thanks!

 

[LDB]

I was in the storage facility where the tractor is over the weekend, and can add the following: It is a 4 spool valve (both caps are the same length, assuming that I am looking at the caps). It has been fairly cold -4 to around +10 F for the lows. The tractor is inside, but the area is unheated. When I started it I had the same problem the bucket dump did not function, and this time the loader down was VERY slow, and "Float" was nonexistent. I freed the "dump position" and exercised the hydraulics and everything came around.

Where can I get a diagram and or a rebuild kit for this valve? I would hate to have to replace the valve; the price is around $700.00 !

 

[Babyfat]

Which valve does your look like? both are 4 spool valves

 

[LDB]

Which valve does your look like? both are 4 spool valves

The one on the right. Are rebuild kits available? How difficult is it to rebuild?

 

[Babyfat]

They have a seal kit around $30.00, prolly not to bad to do haven't had to do one though.

The one we had to do need everything under the caps and for them kits they are around $110.00 each (red/yellow highlight).

 

[LDB]

I have the rebuild kit for the valve, and I am heading north to go through the valve on Thursday night. Any tips? Suggestions?

The parts look pretty straightforward. From what I can gather from examining the parts in the kit and the diagrams; it's basically take the cover off, replace a couple of O rings and nylon washer and reassemble. The detent sub-assembly is pre-installed in the cover.

Am I missing something; or am I over complicating a simple job?

 

[Bulldog]

When we did my brothers loader it was pretty simple. Just take it apart slowly and a drop cloth the catch any small parts that could come out might not hurt. Good luck with it and let us know how it works out.