Loader Control Valve Rebuild?

[RFrank]

Hi all, this is my first post. So, I bought my first hoe...Case 580b. It needs work but overall still has some life left in it. I have the service manual.
The loader won't go up or down. All other hydraulics work fine. If I roll the bucket down and then pull the lift lever and then roll the bucket up, the lift cylinders will hold the arms up. If I then try to lift, the bucket drops. If I engage the lift spool and try to operate the backhoe, it won't, so the lift spool is stopping the power beyond flow through.
If I get the lever in just the right spot...first to the bucket roll then over into lift, the bucket will lift. Somehow it seems like the lift spool is blocking the power beyond circuit, as it should, but is not energizing the parallel passage. The tilt spool energizes parrallel passage and I can power the lift from that if I try to use both at the same time.
It looks like disassembling the loader control valve isn't too big of a job, but I don't want to if that's not where I should start. Are there rebuild kits available for these?
If anyone could offer any advice, sure could use it, thanks.

 

[JerryG]

Frank,
Two things to check.
One. Check to see if you have any quick connectors that aren't seated completely. They can look seated and not be.
Two. Check to see if all of your levers and control valves are centered. Once in a while there will be one that doesn't completely center and it will mess everything up.
Most control valves don't have a lot that can be changed or rebuilt in them. They usually consist of o-rings on the ends of the spools and maybe a change or setting of the relief valve.

 

[kennyd]

Welcome to TBN

It kind off sounds to me like a linkage problem rather than the spool valve?

 

[RFrank]

Welcome to TBN

It kind off sounds to me like a linkage problem rather than the spool valve?

Thanks, linkage was ok and there are no quick connects there. All the hydraulics worked fine (hoe, stabilizers, bucket tilt and roll) it's just the loader lift. It wasn't a gradual failure, it worked fine and then it didn't.
If I pulled the loader control over into roll back and then feathered it into lift, the loader would lift normally. But I had to find that spot. This makes me think it's not the cylinders or hoses.
I took the valve off and pulled both spools out, they hardly even show wear. I pulled the check valves, they look ok too. I'm thinking I should finish disassembling it and take it to a mchine shop and have it baked out. I am concerned about getting the o-fings and seal though. I called the large suppliers and they didn't have parts. The machine is a '72 Case 580b backhoe. The valve is a 2 spool parallel circuit made be Parker Hannifin. Model # D 45040, Manufacturers part # 03033044 Ser.# T
Any help would really be appreciated.

 

[RFrank]

Welcome to TBN

It kind off sounds to me like a linkage problem rather than the spool valve?

I took the vave off and pulled the spools and chec valves out. Everything so far looks good, hardly any signs of wear. I really though I'd see something, now I'm really lost. I think it's got to be in the valve because if I got the lever in a certain spot (bucket tilt then feather into lift) the loader would lift ok. So the lines and cylinders must be ok.

I think next step should be to finish disassembly and take the body to a machine shop to dip and clean, to be sure the passages are clear. I am a little concerned about being able to get the o-rings and seals. I called 3 large suppliers and none had these.
The machine is a 1972 Case 580b backhoe. The valve is a 2 spool parallel port made by Parker Hannifin, Model# D 45040, Manufacturer's part # 03033044, ser.#T, VDP 22 DF 38.
If anyone could offer any advise, sure would be appreciated.

 

[tlbuser]

Sounds to me like you're on the right track, but why aren't you taking it to a hydraulic shop? There has to be some tolerances on the spools and body that need to be checked (other than visual) and I would think a good hydraulic shop will be able to help.

 

[RFrank]

Trying to keep costs down. I will take it if I have to. The service manual describes the spool as "fit their respective bores with slight hand pressure and without noticable side clearance". They both have a slight drag and no side movement. It seems like I should be able to see something. All hydraulics worked well up until the loader just all of a sudden wouldn't go up or down. Seems like an immediate failure would be visible?