580C hoe valve bank refurb

[TheOldMan]

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.

 

[dwloop]

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

 

[GWS]

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.

 

[tloft]

TheOldMan - yep ... what Dave said. Love those pics you put up.

 

[dwloop]

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

 

[TheOldMan]

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.

 

[TheOldMan]

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.

 

[dwloop]

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

 

[TheOldMan]

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!

 

[dwloop]

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

 

[TheOldMan]

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.

 

[alrman]

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!

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!

 

[alrman]

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.

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.

 

[TheOldMan]

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?

 

[alrman]

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

 

[TheOldMan]

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?

 

[GWS]

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).

 

[alrman]

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?
I guess my question is, is there anything I should be looking at prior to re-assy?

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.

 

[dwloop]

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

 

[TheOldMan]

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.