-------------------------------------------------------------------------------- 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.
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.
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
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
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
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.
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
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.
Lets see what you find first, sometimes I can make myself look darn stupid with no effort at all. Mel.
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.
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.
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.
Funny, reading your first post I think you said just the opposite. :beatsme
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
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.
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
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.
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.
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?
The scenerio that boltthrower is describing is classic, have seen it many times, However another scenerio that is possible is that the packing can be blown and the Hydro leveling cylinder can be providing enough lift to help the lift cylinders pick it some as when the loader is rolled clear back if the cancelling linkage is not working the HL cyl will provide a significant amount of lift. Now, follow this closely and think about it as it is absolutely true. If the loader is lifted in any manner and the packing is blown or even the bolt out, the loader will stay up after leaking down a couple inches even with the piston separated from the rod. The reason for this is that after the pressure equalizes across the blown packing the cylinders become simple displacement cylinders, the larger volume of oil leaking by the packing from the butt end cannot go anywhere and the displacement of the rod makes the volume of the head end smaller which makes it unable to accept the larger volume of oil from the butt end thus pressure builds on both sides because the return port is blocked as well as the pressure port with the spool centered. If a gage were inserted in both sides of the cylinder the pressure would be equal. In this case the loader will lower if you pull the lever into the lift position with the engine shut off as you have broken the hydraulic lock by providing a return via the head end of the cyl being open to return and the oil coming by the blown packing will allow the loader to lower as butt end oil leaks away to the open head end. Is this clear as mud, In my 46 year career I have seen this more times than I care to, most recently on a 60XT in our rental fleet. Please any one repost if this is confusing and I will see if I can clear it up, Sorry about the long post. Sincerely Mel
http://www.hydraulicsupermarket.com/technical.html Here's an interesting link that helps explain what you're talking about melben. You're right on the money with your explination... good job. This is another interesting property of hydraulic cylinders that most people might not realize... pressure intensification in hydraulic cylinders ... You might already be familiar with this web site... some good reading any way. OCR
Mel, thank you very much for the effort you put into that last post. Surprisingly enough..I did follow it (mostly). It makes perfect sense to me, I had wondered if somehow the Hydro leveling cylinder might be the key. I haven't had the hoe very long but I think it wasn't leveling the bucket as it was supposed to. When I was first thinking that maybe this was a factor, I looked at where the hydro cylinder connects/pivots at the loader frame. I thought the fact that it connected directly below the loader pivot point would limit this cylinders ability to offer any loader lift assistance, looked like it would just push against the pivot point rather than push the frame up. But this seems to be the most likely scenario. The only thing that wasn't adding up for me though was when you said: "In this case the loader will lower if you pull the lever into the lift position with the engine shut off as you have broken the hydraulic lock by providing a return via the head end of the cyl being open to return and the oil coming by the blown packing will allow the loader to lower as butt end oil leaks away to the open head end." The difference is that the engine wasn't shut off when I pulled the lever into lift position....then I realized the loader would still drop even with the motor running IF the packing(s) is blown. Also, I was thinking that the odds are probably against packing in both cylinders failing together but, I had noticed since I got the hoe that every time I raised the loader, the left arm seemed to rise a little before the right side. Maybe the right side packing has been blown? I didn't think so because it seemed to have plenty of uplift power. I made a set of forks for the bucket and it was no problem to carry a stack of trees. Oh yeh, now it comes out, no wonder his loader is broken he's carrying stacks of trees around! Can you recommend where I should buy the seals and spanner wrench. And is there a universal spanner that would fit all the cylinders on my 580b? It's great to have some place to go to ask these questions, really appreciate everyone's help. ...Frank
Thanks OCR. wow I went to that site and it'll be quite helpful. I bookmarked it. And I agree, Mel's explanation was excellent. Frank
We are an authorized Case dealer and we keep an adjustable spanner at the parts counter to rent as a courtesy to our customers. Maybe your local dealer does the same. We as a dealer have had opportunity to try other brands of packing kits than Case and we seem to have better luck with OEM packing kits and do not bother with off brands Case is constantly improving the seals and bearings. In your note you said you had your motor running, no difference to the return side of the circuit except a few lbs of backpressure maybe , your explanation should have answered your own question when you tried to raise the loader the loader went down. We have been talking about packing but don't forget the broken or backed out bolt as our other poster said it is the most likely scenerio, the packing references were for illustration. The unit would probably lift to some extent if the piston was securely fastened to the rod. I have seen what he described many time where the piston would seal against the rod end and the cylinder would work that stroke then quit again. mel
You're more than welcome Frank. Looks like you're doing a good job at trouble shooting your problem. Hydraulics are not as simple as would seem, at first glance. You statement about both packings being in failure mode is a good rationalization, and you are correct about the odds, one would not normally expect that to be the case (no pun)... You have a parallel circut... so only one packing failure should cause the symptoms...ie, what happens in one cylinder, will cause an effect in the other. The oil in the good cylinder will transfer to the bad one, and let the loader down. I had to do some head scratching on that, and I could be wrong. Mel definitely knows what he's talking about, so if I'm wrong... he can probably correct me. Interesting problem here... you're doing good. OCR
Ocr, I think you have a perfect understanding of it, with both work ports closed, the unequal volume butt to rod end make a transfer of oil impossible if it is going in the big to small volume direction so the SYSTEM as a complete entity becomes a simple displacement cylinder, the fact that one cylinder may be perfect means nothing. NOW, if the rod is being extended(rod being pulled out)by external forces a void can be pulled allowing the cylinder to have a area of perfect vacuum inside itselfdue to lack of the unequal volume effect!!!. Isn't hydraulics neat. I was going to write more but I've already covered it in my previous post and I'm a hunt and Peck-er so if you are at all in doubt reread. the system cannot go clear down as long as oil is trapped by the workports.
Write more: So am I... and a terrible speller... and it takes me seemingly forever to type out a post, but it's an interesting topic... so have at it... :thumbsup OCR PS: Some of the members might be happy to know that... :lmao
OCR, Stay in here with me , your input has made my job much easier. Mel
Thanks guys. I was thinking about it some more last night after my post. I realized that all the symptoms that i have would just as easily occur with just one of the two cylinders failing. As you said it's a parallel circuit. If a 'bypass' is occurring either from the packing or detached piston, then all oil in that circuit should flow through the void back to the valve. Good advice on the seals and spanner wrench, thanks. I'm thinking...with another 1/2 dozen or so cylinders, I'll probably buy a spanner. I'll let you know what I find. Probably a week or so before I can get back to it. Frank
Stupid question After reading this thread from the beginning, I can't find any mention of a linkage problem. Did you verify that the lift spool is moving the full amount it should when you move the lever? Or better yet just disconnect the linkage at the spool and move it physically yourself (engine running of course) and see what happens? Maybe were all overanalyzing this. Its hard to troubleshoot when you cant put your hands on the machine.
Nothing stupid 'bout that question bolt thrower. I don't think there is a problem with the linkage but I will try that...disconnect the linkage move the spool fully. I do know that it has full travel in the down direction because it will move all the way to the float detents. The linkage looks OK and the amount of travel feels the same at the lever, but I'll check it. Thanks, Frank
You were right 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." bolt thrower, I finally had some time to get back to my project and I did what you suggested. I disconnected both rod ends and pulled on each...one rod pulled out completely (without the piston). I was planning on leaving the lines connected and the cylinders mounted. I had read an earlier post that said I could replace seals and packing by keeping the cylinder tilted upward and pulling the rod and piston assembly out. Does anyone have a suggestion on how I can get the disconnected piston and bolt out of the cylinder? This is a 580b and it has the split piston. Thanks, Frank
Glad you found it , it or blown packing were the possibilities. I have done many of these, dismount the cylinder barrel after removing the gland. Get a good block of hard wood and bounce the barrel down on the open end. It will come out, just takes a bit. Mel
Thanks Mel. You've just saved me some grief. I was trying to come up with something that I could put in the cylinder, through the piston and either hook it or some kind of expanding end. I'm going to replace the seals and packing in both while I'm in there. Should I use loc-tite on the bolt to reattach the piston? Thanks, Frank
Yes, thoroughly clean all parts with brakeclean, use loctite cleaner/primer, follow directions and use 271 loctite and tighten. Mel
580B control loader valve If you cannot fix I do have a good used Valve for your 580B backhoe loader Parker . my e mail is [email protected] thank you.
I finally was able to get back to it and finish up. So, the problem was the bolt connecting the piston to the rod worked loose and became wedged down in the bottom of the cylinder. The bolt end had been jammed into the cylinder wall. The hardest part was getting a heavy hook and chain around the bolt so I could pop it out of there. The bolt put a slight dimple in the cylinder and a small raised burr. I turned a wooden plug on the lathe just slightly smaller than the cylinder diameter. I drilled through the plug and fastened it to the end of a length of thread-all. I fastened a narrow piece of 400 grit paper around the plug and bottomed that in the cylinder and spun it with a drill. After 5 or 6 paper changes, the burr was gone and the walls weren't scratched. I put it back together, changed the other lift cylinder seals and it is working fine. Thanks for all the help, Frank