Started cleaning up the spool valves and secondary relief valves today. We had pulled the entire bank off the machine and I disassembled it today and started cleanup. Fortunately, all the spools look to be in great shape. There is a little corrosion on each spool above where the seal sets, just below the control rod hookup. I'll probably just hit that area lightly with 600 grit to clean them up. the secondary relief valves however, are a different story. They are a mess. Evidently some one has used locktite on all the adjustment screws, because it's impossible to remove the nuts. 2 of the relief valve assys I haven't gotten apart yet, soaking them in Kroil. Missing orings on the load check plug in every valve. So full of gunk, don't know how they'll clean up. Work on it again tomorrow, I'll post some pix when I get everything cleaned up.
TheOldMan, Looking forward to seeing your pics and hear what you have to do to straighten that out. Hang in there, sounds like you are doing it right! Dave
TheOldMan, when you get your cleaning tank there is a little trick I found works good for cleaning out valve bodies and things with holes throughout them. First, make a small restrictor to slow down the pump pressure on the cleaning tank. Then get some small rubber tubing or that clear stuff they use on fish tanks and attach it to the end of the flexible line spout. Makes it pretty handy to push the small tubing down into the valve body holes and flush gunk out. Also keeps it from shooting out another hole and getting a face full. I use diesel for the cleaning fluid but there are better cleaners out there I'm sure.
TheOldMan - yep ... what Dave said. Love those pics you put up.
TheOldMan, I was thinking of your comment about the locktite on the check adjusting screws. I assume you know that low level heat will make most locktite release? I hate to assume... If you do please ignore me. Doesn't take much, usually 400'F or so, not red hot. I use old style mineral spirits in my cleaning tank. Lessens the smell in my shop. HTH Dave
Well, I didn't get the new cleaning tank. My son had it, and said he'd bring it to me, but it was all the way backin his storage shed, and hard to get to, so he brought back the old one I gave him about ten years ago. What goes around comes around, i guess. he did bring me about 7 gallons of cleaning fluid. Spent the day rewiring everything, pump lights etc. all had gone bad. I'm aware that locktite softens with heat, but I'm glad you replied, I'd probably had those little buggers red hot. Haven't started on them yet, but hey're pretty small, about the size of a dime, with what looks like a long set screw through them. Maybe I'll donate a well used pair of vise grips to the heating process. Look at them tomorow.
Got the setscrew adjusters out of all the secondarys today. Here's what I found. Under the locknut, there's a washer with a flat on the inside. The socket head screw they use has a flat about 3/4 down it's length from the inside. i assume that the reason for this washer is, that being on the outside of the keeper and the flat not extending all the way, it is impossible to screw the adjustment so far that the screw ends up inside. On this machine, every adjuster (but one) was run down tight against the washer, as far as it would go, stopped by the lack of further flat on the screw, then locktited. In order to get them loose, I clamped an allen wrench in the vise, with the long arm pointing up, and set the assy down on the allen wrench, then heated with a propane torch. Cooled, then grasped the outside of the keeper with a pair of vise grips and was able to unscrew the nut. The washer, however, was glued to the keeper with the locktite, and had to be twisted to remove.
Sounds like a mess! The locktite will come loose better when hot... I am trying to envision the operation with the allen in the vise, you trying to hold the assembly and heat the bolt, etc. That had to be a challenge! Dave
One of the odd things I have learned while working on this valve bank, is that there is a "different" o-ring on the plug in the load check and relief assys. #14 on page 350 of the parts manual (P/N G33686). This o-ring is made of a white looking material, and Case wants $3.18 ea for them. GWS said they were all missing from his valves, and I found one and a half total and there should be 16. Anybody know what this thing is made of, why does it deteriorate, why does it cost so much, and can it be replaced with a regular oring? I'm surprised someone hasn't come up with an o-ring kit for the valves. So far, I'm up to 80 rings, approx $130, and still counting!
TheOldMan, I found this: G33686 5331-00-556-8288 O-Ring Material: Rubber polyurethane Cross-Sectional Height: 0.067 inches minimum and 0.073 inches maximum Center Hole Diameter: 0.609 inches minimum and 0.619 inches maximum On this site: http://fsg-53-hardware-commercial.parttarget.com/o-rings-G311951-2_G-375-B-120-AA-A.html I have no idea if it accurate... I have used their information before with success though. HTH, Dave
I ran into a Case mechanic from Trekkor Tractor in Orlando, working on one of the local guys 580L, and he was very helpful. I just ordered a whole list to replace everything. from them. Very nice folks to deal with. Parts man said all these o'rings came in quantity lots, but he would break them up, so if anybody out there is working on this valve, he probably has all of them in stock after next week.
The white orings are a special for Case. They are alot harder than 90 duro, able to be purchased anywhere. I have been out to machines that have not long been repaired by hydraulic shops that have used common orings & they disappear alot faster than those white ones. I only like to use genuine orings in valves - cause if you mismatch size or duro - all the work you have done, will be for nothing, as it will need re-doing straight away...... $130 is chicken feed for your genuine parts to date - a Case dozer control valve, full reseal, will leave you with little change out of $1000 for parts only - ouch!
What that means is that the orings come in packets of 5 or 10 - don't be fooled into thinking they are doing you a big favour - they should stock those anyhow.
I hope I've ordered it all, been over the list several times. I don't think any Case dealer is going to give you a price break, but I agree after all the labor involved in this, I'm certainly not going to second guess on the o-rings. Two of the adjusting screws for the secondarys were broken off, they are 1/4-20 x 3/4" ball end set screws with a flat about 3/4 of the way up. Case wanted 9.20 ea for them. Ordered a pkg of ten 1 1/4 ball end set screws from Mcmaster Carr for 6.88. I assume that the flat w/ the special washer is to keep from screwing them all the way in. I figure if you buy a little longer screw, there's no chance of doing that. I may locktite them again after I get them set. Let the next guy fight them off again. The top fitting (hose connection) on the boom valve has an insert in it they call a restrictor. Looks like a standard o-ring boss fitting with the inside diameter drilled out to allow inserting the restrictor. The 37* end of this fitting is dinged about halfway down the flare on the inside. I don't know if we did this removing the valve bank, or if it was done previous. You can see the sealing area ring on the flare from previous use, and the ding is all inside this ring. The ding is smooth so that would not effect sealing, the question is, does the fitting seal on the outside edge or the inside edge of the fitting? Case says this is a special fitting and "contact dealer for pricing". I wonder if I cleaned the are good with brake cleaner and used some JB weld if it would work, or am I taking a chance of a hunk of JB weld ending up in that valve?
There is a repair method for JIC fittings that are damaged - a thin metal ring which clips onto the male flare, which basically gives you a new sealing area. - they work well. http://www.flaretite.com/flaretite.php
Everything is slowly coming together to start re-assy of the valve bank. Still waiting on the o-rings to arrive. This all started because the bucket was underpowered (possibly the whole backhoe assembly). I really haven't found anything to attribute this to. The missing special o'rings on the secondarys was about all. Would this lack of hydraylic power normally be attributed to leakage past a spool? All the spools look bright and shiny, see no obvious wear spots on them. I understand that each of these spools and thier cylinders are ground to fit at manufacture. Wouldn"t there be an obvious tell-tale mark on the spool if it were bypassing? I'm almost afraid to mike anything, could probably do more harm than good, and I have no idea what the tolerances should be. I guess my question is, is there anything I should be looking at prior to re-assy?
I'm not by any means qualified to give an expert reply but I would think possibly the secondary reliefs or the inlet pressure relief valve may be dumping pressure to soon. I know from reading the manual that they are there to protect the cylinder rods from being bent. If some parts of the hoe have good pressure then it can be tracked down to the specific valve. If the hole backhoe is weak then I would go for the common point (inlet relief valve or back to the loader relief).
The things you have found will all affect digging power - oring at power beyond; orings at load checks; main relief valve with low pressure. Spools give very little problem in a control valve ever - the amount of leakage that would ever occur there would only cause a slight creep in the hyraulics, while holding something under load, they will not affect speed or power in any way (unless not fully open) Put the valves together with new seals, check & adjust the secondary reliefs pressures with a hand pump, & address the main relief valve problem with a new poppet & seat, adjust relief to spec if possible - you should be amazed at the difference.
TheOldMan, you stated earlier you had bought a porta-power like pump to test the secondary reliefs? I would really like to see some pics of that setup when you get it going! Dave
I ordered the fittings necessary (as per service manual) to connect the pump to the valve bank. When I get it together, and if it works, I'll post pix and specs.
Here are a few pix of the backhoe load bank work in progress. The port-a-power setup seems to work ok, kind of a pain making sure the resevoir doesn't run out, it's pretty small. I'm about stumped on these secondary relief valves. Page 4002-3 of the service manual outlines the pressure settings for these, and it ranges from 700psi to 2400psi So far, I haven't been able to get the gauge above 1500 on any of them. This is after installation of all new o-rings and seals. Everything was cleaned thoroughly prior to re-assembly. Specs call for oil temp for adjustment to be 70-80 degrees, and the oil is not that warm, but it appears to me that at a cooler temp, the oil would be thicker, and pressure adjustment range should go higher. Is this correct? As you can probably tell, I've got a heat lamp on the valve at the moment, letting it heat up, and intend to warm the oil before I try again. Also, when I reach the pressure on the gauge where you can see the valve open, if you let it set, the pressue drops back to 0 pretty quickly. I'm applying pressure at the work port immediately adjacent to the valve being adjusted. Anybody help me on this?
Oil temp is not your issue - I have only ever adjusted the valves at ambient temp. ( not in snow!) I'm assuming you have resealed the load check valves as well? These need to be 100% to get pressure. I would have thought a hand pump like yours would do the job - but I have never used one like that to be able to say for sure. It is possible the pump just does not have enough oil flow to be able to work the reliefs effectively ......... You say they leak back to zero pretty quickly - that does not seem right as they usually hold a little pressure - will they hold any pressure at all ? If you dead head the pump will it hold pressure?
Yeah - the first thing I did was dead head the pump, and pumped up to 5000psi and it held. I left the heat lamp on for four hours, and the valve was warm enough that you didn't want to leave your hand on it. The oil in the chambers at that time was warm. Yes, I replaced all of the o-rings in both sides of all the valves. You can see the valves release, and by adjusting the allen screw, can rais that point up to around 1500psi, but that's all. I just opened one of them up, and everything looks good. There is a ring worn around the face of the relief valve poppet, but nothing you can feel with a finger nail, more like jus a dull ring. They leak back almost immdiately to 0. Is there any chance you have to engage the spool valve to set these?
The spools must remain in the neutral position while checking or the oil will just transfer from A port to B port. I didn't understand if you replaced the white orings on the load check valves pictured below ( pic shows a later model oring configeration) These orings need to be in place to build pressure.
It's just hard for me to believe that all 8 of these valve assys are defective. they were pretty gunked up when I took them apart. Does anybody out there have any more ideas? Is thier a common denominator that could affect all 8 assys? The relief valve kit is pretty expensive, and the only parts included that haven't been changed are the poppet valve and valve body that contains the seat. I hate to spend the money and find out that's not my problem. There must be something I'm missing.
I'm trying to help you, but I can't if you don't answer my questions ......
Yes, I did replace the white o-rings. I don't know how that section of the valve works, that plunger is attached by an extremely light spring. I thought maybe that spring was just to hold thngs together during assy. The load check poppet that is attached by that spring has some slight galling on the face of all 8 of them, but didn't look like anything beyond normal wear to me. I'm questioning if this pump I'm using is developing enough volume. I've seen wobble pumps for emergincy deploymet of aircraft landing gear that look a lot like the one pictured in svc manual. Do you have to keep a continuous flow through the valve while setting it, or do you just pump it up to where it relieves?
Ok, another name for these valves is port reliefs - all 8 are isolated from each other. So there is nothing that is common to all of them. I have checked individual sandwich sections many times & they will leak some oil as you build pressure. So my guess, would be as I stated earlier, that the problem is a lack of oil flow from the hand pump. The wobble pump you are describing sounds similar to what I use (below) These pumps are double acting, pumping on up & down motion. While testing a valve constant pumping action is required to overcome the leakage happening at the port. It could also be adjusted on a test bench - the type that your very friendly hydraulic supply/repair company would have....
Thanks airman. I'll contact the hydraulics place as soon as they open.
Backto the drawing board! Local hydraulic shop wants $100/valve to adjust on flow bench. They suggested that I remount the valve bank and rig 2 gauges, one to each work port on each valve, engage the spool and adjust the relief that way. I may have to do that unless I can get access to a better hand pump.
Looks like the way to go here is to remount the controls and see if I can set them on the tractor. I found a thread on these (what are these set screws) that gives me a pretty good idea of how to do it. Airman, in that thread, you explained the difference in settings between full flow and hand pump. You were discussing 580B specs. In the C svc manual, pg 4002-3, it calls for full flow setting @ 1000 +or- 75psi. It makes no differentiation for the boom A port, which is set at 700 for hand pump. Would the proper procedure be to set them all @ 1000 under full flow? Here's how i forsee doing this, please advise if I'm wrong. Re-install valve and connect only oil supply and return, with all A & B ports capped off except the spool under test. Both ports would have a gauge connected. With the engine running, throw spool one direction and adjust that valve for 1000 psi, then throw spool the opposite direction and adjust the other valve for 1000psi. Move gauges to next set of ports and set that one. Sounds easy, but I'll bet it's not.
I have never used the 'full flow method' to test the secondaries, reason being, I have always had a hand pump. The pressure settings would have to all be different (as per the hand pump settings) but the fact that the manual does not give the pressure settings for 'full flow' indicates to me that it is not really recommended. Note that you need 10GPM to do the test - without a flowmeter it is a guess - what RPM do you do the adjustment at??? Boom A port moves from 700PSI (hand pump) to 1000PSI (flow) - maybe because of the low pressure setting the higher flow of oil makes a difference for this one port?? Do you set the other valves at same as hand pump pressure?? - not sure, at a guess I would say yes. Another problem - if your main relief still wont go over 2050PSI you may not get enough system pressure to check them..... I recommend finding a hand pump, I like the tried & prooven method - but you have been game enough to do what you have already done, when many would have given up, give the 'full flow method a go, it will only cost you your time & well, it might work ......... it's your call.
I would love to locate a handpump I could beg borrow or steal for a day. The valve bank is setting on the bench, and if there is a problem it has to be much easier to address there than with the bank in the machine, but haven't had any luck finding one. You've got me thinking now about what the other reliefs should be set at. I was assuming that because the 1000 psi setting was in the center of the column, it was meant to encompass all the settings, but it surely makes more sense that because the Boom A port is the only one lower using the hand pump method, the 1000 psi thing would apply to it only, and the others would get set to the hand value.Going back to the (what are these set screw) thread, it appears that this is the case. As you know, I had a problem with the main relief valve in the loader (pwr beyond) When I get this valve bank re-installed and capped off so I can operate the pump, I'm going back to that problem and solve it before i go any further. In the event that I do have to replace the secondary relief valves, there is an updated kit (G109449) that replaces them. Is there a similiar updated kit for the primary relief valve?
Thought I'd upload some more pix. set the backhoe valve bank back in along with the mounting plate. Much easier job than I thought. I've been dreading this since I pulled it all out. I think it went in easier than it came out. Now all I've go to do is make all those hose fit back in the right place, right after I set the secondary reliefs. We color coded all the hoses with tie wraps, so shouldn"t bee too bad. PO installed some new hoses to the valve bank, and I guess he thought if you made each one 6" longer it would fit better. That makes it tough.
Making progress!!! Got the control tower installed and adjusted. All of the work ports are capped off except stabilizer valve. Checking for leaks, stabilizers seemed to have more power than I remembered. Installed the pressure gauge on the power beyond section of the loader valve, and I now have 2200psi vs. the 1100 I had prior to working on the backhoe valves. Still can't adjust it above 2200, but I can hear the main relief valve bypassing with the bucket rolled all the way back. Never heard that before. This weekend I'll replace the power beyond o-rings and see if that does anything. I replaced it, but out of a universal kit, don't know if that was the right one or not. I have the right one in stock, so that's the next step. I would love to be able to dig without rebuilding the main relief. Wish me luck.
That's good news TheOldMan! Glad to hear
Good luck
OK. Replaced the pb o-rings and nothing changed. Holding the throttle wide open, the bucket curled back, pressure gauge connected to the 1/4" plug on the pb section of the loader valve, I can get a maximum psi of 2150-2200. Backing the set screw adjustment out about halfway the pressure begins to drop, but seems to have no effect above that point. I am cycling the valve between each adjustment. I think I have 2 choices here, leave the adjustment near the closed end and set the secondarys on the bh load bank to a point a little below the primary and see what happens, or go ahead and pull the primary relief apart and see if I can find anything wrong. I've tested the pump with a flow meter, and it is good. My first inclination is to adjust the secondarys a little and put it back together, but I've got all the work ports on the bh capped off, and if I remove them and re-connect all the hoses and still have to get into the primary, I'll have all this to do over again. Looking for suggestions. I've gone so far with this thing, I hate to leave it half cocked now!
I had started a new thread, revealing my obvious mistake. Airman advised I should document everything under the same thread for continuity. I agree, so here goes. I pulled the loader valve off the machine to work on the main relief valve. When I got it cleaned up, and laying on the bench in the same orientation as the picture in the parts manul, it was pretty obvious that I had been adjusting the wrong valve. I was adjusting the secondary relief for the loader. Not much wonder that I couldn't get the pressure up to snuff. I had pulled the controls off too, as they were very sloppy and needed rebuilding. So we re-installed the loader valve (now nice and clean) and I rblt the controls. The worst wear was in the pins. It appears that the links are pretty hard. I found some plated 5/16 pins to replace the worn originals. Seems the plated ones are just a couple of thousands bigger. Had to polish the holes just a little with a 5/16 drill bit, and everything fit pretty tight. I replace the 1/2" shaft with some electric motor shaft cutoffs I had lying around. The 5/8 shaft that is part of the control handle was in pretty good shape, pretty hard, I think. I carefully bored the cast fitting that goes on it with a 3/4 bit, and installed 4-1/2"x1/2" bronze bushings from Mcmaster Carr end to end, one of them drilled for the grease zerk. Not tight enough to qualify as a press fit, but since they are captive on both ends, they can't get out of there. Had to use a little valve grinding compound on that shaft to make everything fit, but after cleaning off the grit and greasing, it is pretty tight, and I'm quite satisfied. I had previously replaced 1/2" shaft and pins in the backhoe controls with equal sucess. Once I had the controls replaced, and having previously hard capped all of the work ports on the backhoe valve, we warmed up the oil, and the main relief valve pressure was adjusted vey easily to 2500psi.
Thought I'd better break this into parts so it doesn't read like a book. The main relief pressure must be adjusted higher than operation pressure to insure that the secondarys don't open each time a valve is selected. I rigged 2 pressure gauges, on on Port A & one on Port B, and while the wife held the control handle in the proper position, with the throttle wide open, I checked the pressure on each one, and adjusted as per the svc manual under full flow. You can't adjust with the pressure applied, have to adjust then check then adjust etc. The only one that didn't come into spec, was the boom A port, was supposed to be 1000psi, couldn't get it below 1400 backed all the way out. Re-installed all the backhoe hoses, readjusted main relief to 2300psi,and went to dig. What a difference. Acts like a backhoe. Dug about 10 minutes and blew a dipper hose, knew it looked bad, but had to try. So new hose is installed, but it's quitting time. I'll feed it some more hydraulic fluid and try again this weekend. Hydraulic oil refining may be a better investment than gold!
All that new found pressure will surely sort out any weak / problem hoses. I am a little concerned about the fact that you could not get correct pressure at Boom A port. The adjustments are "full flow" method not "full RPM" method. They are supposed to be at 10GPM ...... Full RPM would mean you have adjusted at approx 24GPM - at a guess, to adjust at 10GPM, I would have thought to adjust at about 1000RPM - without a flowmeter it is only a guess.
Thanks airman, hadn't thought of that. I'm gonna try it for a while, if I experience too many p[roblems, I'll probably have to back up. I've got that boom A valve backed all the way out, so don't think that will be a problem. I adjusted them at full throttle, so would 10gpm/1000rpm have been lesser psi? If that's the case, I probably have them all adjusted too low? What do you think?
Hey Old Man, If you can't get below 1400 on your A port, is there a chance that it is the wrong port relief cartrige. Most of those have a pressure range, if your A port is made for a higer range, the internal spring may just have bottomed out at 1400. could be the wrong spring in there too even though it is the right part number, assemblers have been known to make mistakes.
I don't have any idea. As i disassembled the valve bank, I placed each secondary relief in a labeled plastic bag, rblt them one at a time, and insured they went back in the same hole. Someone else had been into that valve bank before, because the bodys were numbered with a ***** punch. Case has a replacement valve kit (G109449) that is an updated version, but they make no indication that they are not all the same.
Hooray - Hooray -Hooray. (I would have said hallelujah, but I didn't know how to spell it). Just got the first pine stump out of the ground. The old C dug like a good girl. Found afew more problems, but nothing earth shattering. I bought this 11/20/11, so today is 4 month anniversary and it finally digs. I never said I was fast.
I'm thinking the higher flow of oil, holds the valves open longer. It may just be a problem on the boom A port because of the low setting. Seeing as how your handpump could not give enough flow to give correct pressure, with the other higher pressure settings - the flow of oil certainly has an effect with the spring tension in the valves. I reckon your valves may be adjusted a little too high - but I can't say for certain, as I've never adjusted them using the "full flow" 10 GPM method before ...... Main thing is that you have adjusted boom A alot lower than B port. That will stop the boom cylinder rods bending........:yup Like you say - see how she goes - good to hear positive results from your hard work :thumbsup
I don't know how close I am to the recommended settings, but if I was going to bend anything, I would have done it today. I decided i was going to see what it would do, and I worked it hard. I've got to go back and set the secondary on the loader valve, because with the tractor up on the outriggers and the bucket, the bucket leaks down.
Thought I'd add one more post to this. The valve bank all seems to be working very well, and certainly has a lot more digging power than it ever had before. I am experienceing one problem.. The 4 secondary releif valves that point up on the valve bank have evidently held water on top of them at some time, and are pretty rusty. I had cleaned them up as best i could prior to reassy, but now they are starting to leak, one by one, around the adjusting screw. So far I have pulled 2 of them, and the rust, although not down in the barrell extends down as far as the c clip. Evidently when installing them, the oring on the piston is damaged going past this rust. Each one that has leaked has a sliver of oring on top of the piston. Probably going to have to figure out how to remove the rust and smooth that area out without damaging the rest of the barrell or replace all 4.
TheOldMan, if you are still here on this thread. From what you wrote in the thread it looks like the backhoe valve system can be adjusted without the hand pump method? Also, where did you find the caps that you used to block off the ports on the valve. I am thinking there are caps that will just hold fluid under no pressure and others that will hold pressure? Also, where did you find a flow meter?
Here is a picture of the check valve plug with an o'ring attached. This is for a Case 480C 26BK-H 1976-1980, Plug G33084 and O'ring G33686 (white O'ring feels pretty hard). Trying to solve hydraulic drifting or ghosting when under pressure, when disassembled I found no O'rings on the check valves all 12 are missing. Will update once back on machine.
update once installed all new o rings. Drifting was gone and machine dug strong with no more issues. Other than the head gasket went which was a straight forward repair