Is it difficult to rebuild 580b loader control valve

[RFrank]

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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.

 

[RFrank]

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.

 

[Phil]

I don't know if the secondary relief valves can be switched around on that valve or not. I just realized I gave away my 580CK parts book . Seals should not be a problem at any good hydraulic shop, they still sell Parker products up here. Maybe they would look it over for you. Did it start doing this all of a sudden? A loader valve section may be cracked, spools centered okay? There are a few on this forum that work at Case dealerships. Too bad you couldn't find a used valve assembly, not sure if the CK valve is the same. Phil

 

[RFrank]

Thanks Phil. It did start this all of a sudden. I was leveling some dirt and then at the end of a run it wouldn't lift. As far as I could tell the spools were centered. I was able to lift the loader if I energized the parallel circuit (or blocked the flow thru) by first starting to tilt the bucket and then moving the lever over in the direction of lift. So far, the valve looks good. I don't know how to check it internally. Frank

 

[melben]

Don't overlook blown piston packing , valve problems were so rare that I would not have expected you to find anything there. if you indeed do not find anything put it back on, heat the oil in the system with another circuit, then activate the loader lift , hold it there under lift and check both cylinders for heat at the inlet fittings. if the clinder is leaking internally it will get hotter than a skunk and you found your problem. Mel

 

[RFrank]

Thanks Mel, I'll check that. The reason that I really thought it was in the valve was because the loader wouldn't budge up or down unless I moved the lever toward bucket roll first and then sometimes I could catch a spot where the loader would lift normally.

 

[melben]

If it does turn out to be a blown packing or a piston stud broken or backed out I will try to explain why you were able to lift it as you described. mel

 

[RFrank]

Ok, thanks Mel. I will put it back together and try these things. It'll probably be about two weeks before I can get back to it. In either case, I'd still like to learn how it could still lift, if you wouldn't mind explaining.

 

[melben]

Lets see what you find first, sometimes I can make myself look darn stupid with no effort at all. Mel.

 

[RFrank]

ha ha. I know what you mean. I used to think I had all the answers, now I'm not even sure what the questions are. Frank.

 

[bolt thrower]

I'm with mel, youv'e got a piston retaining bolt or nut thats backed off all the way in one of your lift cylinders. If you pull the pins out of the lift cyl rods, and pull on the rod, I bet one will come right out of the cylinder- with no piston attached to it! Another way to check is plug the lines going to the lift cylinders and then try your power beyond functions, I bet they work.

 

[RFrank]

Before I took the valve off, all the hydraulics worked fine (power beyond and bucket roll). Except, only the bucket lift or down didn't work.
When I would try to lift bucket or push down against ground, there was no change at all to the engine rpm it would be as if the spools weren't moving, but they were. I got the sense that no fluid was being sent to the fel in either direction (everything else worked fine). I don't have a pressure gauge, after reading many threads and learning, I should have verifyed if any fluid was going out or not and at what psi.
Mel, I should have held the valve and then felt the inlet on the cylinders to see if they were warm/hot, like you suggested, but already had it apart. It seems like maybe if the fluid was going through the cylinder around a blown packing, then wouldn't I still hear a slight change in rpm from the pump strain? Frank.

 

[bolt thrower]

Before I took the valve off, all the hydraulics worked fine (power beyond and bucket roll).

Funny, reading your first post I think you said just the opposite. :beatsme

 

[RFrank]

No, it's the same as I first described it. All the hydraulics worked fine except the loader (or bucket) won't go up or down (the lift). The bucket roll or tilt had no problems nor did the backhoe or the stabilizers. I probably could have worded it a little better, sorry for the confusion. Frank

 

[bolt thrower]

Well either way my money is still on a detached piston in one of your lift cylinders. If the packing was blown you would have had a drift problem. If you disconnect the lines on one end of the lift cylinders and put oil to the other end you will know which cylinder has a problem.

 

[RFrank]

Well...I put the loader valve back together and reinstalled it. I did what you suggested.
I warmed the oil by working the hoe and dumping / rolling the bucket. I held the valve in the loader lift position for a minute (still no lift on the loader). Then I went and touched both ends of both lift cylinders and they weren't hot?

Then I put my hand around each of the return hoses and moved the valve to lift, I could feel the oil moving through (loader didn't lift though).

I loosened the return line at the end of each lift cylinder (one at a time) and the moved the valve to lift. A good amount of oil (at least an 1/8" stream) leaked at each one.

This sure seems to be what you've suggested, either blown piston(s) packing or detached piston. Next thing I'll do is rebuild the cylinders.

Something that isn't adding up for me though is that I can still get the loader to lift IF I keep foolin' with the valve by going over into bucket roll back first then feathering it back into lift. When the loader lifts, I can then let the valve go to neutral and the loader stays up (This would seem to cancel the blown piston packings or else the loader would drift down?). While the loader is being held up in neutral if I then try to move the valve directly into lift, the loader drops-quick. That still seems like something in the valve.

Would it be worthwhile to swap the loader lines on the valve to the bucket ports since it works. Also, if it matters, this is a 580b machine and it has the split pistons in the cylinders.

Where would be the best place to order the cylinder rebuild kits?

Thanks for any help...Frank

 

[IH270A]

I had a problem similar to this on my old machine , and found it to be a broken spring , on the end opposite the actuator handles on the spool .. seems it would not center up right and was causing the flow to be interupted , untill I moved it around just right ,, but I don't know about the bucket droppin suddenly , mine never did that

 

[RFrank]

I had a problem similar to this on my old machine , and found it to be a broken spring , on the end opposite the actuator handles on the spool .. seems it would not center up right and was causing the flow to be interupted , untill I moved it around just right ,, but I don't know about the bucket droppin suddenly , mine never did that

Been there...I had the spools out and they look good. I was actually surprised at how good they look (after 36 years). The spools were smoothe, no grooves, nicks or wear spots. The centering springs and seals looked good too. The two check valves (springs and poppets) looked good too.

 

[bolt thrower]

The piston has a hole in it for the bolt that fastens it to the rod. When you retract the rod the oil moves the piston away from the rod until the oil goes through the hole and back to the tank. When you extend the rod the oil pushes the piston to the rod and seals off the hole. the cylinder works correctly until you try to retract it, then the process starts again. These are classic symptoms. Your packings arent blown.

 

[RFrank]

ok bolt thrower, thanks. i'll start with what you suggested in an earlier post...remove the rod pins and pull the rod to see if it (they) are seperated from the piston.
Is there an adjustable spanner wrench available that I could use on all the cylinders?