Case 580B Weak boom rams

[KevinF]

I have a 580b that I just finished doing the R&P on. I had never used the backhoe prior to Saturday.



Upon doing some digging, I concluded the boom rams seem very weak. I don't know if maybe this is because they have been retrofitted (see photo, they are not OEM, but do look to be the same size) or if the controls are bypassing some fluid. The loader has good pressure. Digging seems to work well by using the bucket and the stick, but then if I extend boom and stick out to put the dirt out off the the side, the machine has a hard time lifting the boom again to draw it in. Doing anything simultaneously like moving the boom and the stick in at the same time results in the boom falling. A little disappointing, hopefully the fix isn't too terrible.

For those of you who know the controls better, does this sound like a control valve issue? Sorry I do not know all the correct nomenclature for these parts.

The reason the boom rams were retrofitted is because one had a dent in the outside of the cylinder.

 

[melben]

If I had a Case of that vintage if it equipped with the Case control valve I would replace all the orings on the secondaries and check valveplugs, they were notorious for failing after age and lots of hot oil and that caused a lot of interaction between systems.

Do yourself a favor and only buy Case OEM orings as they are made of a different harder compound.

One other thing that I have seen is the control levers bottoming in their slots due to worn pins and linkages causing the spools not to be opened fully, this causes a loss of flow/pressure. I have lengthened the slots as a stopgap on some.

 

[AllDodge]

No case dude here but you said the pressure is good but everything the hoe is doing tells me that it is not. What hydraulic pressures are you getting?

 

[KevinF]

I haven't got a gauge on it yet, I may only surmise that the pressure is okay because it has no trouble quickly lifting a bucket full of dirt with the loader. I would like to test the pressure in the next few weeks as well.

 

[Bill Smith]

With the boom in the air straight out and no one at the controls ,Does the boom slowly drop .That wood be my first test . I would not tie into the control valves until I have ruled out boom cylinder piston bypass .

 

[KevinF]

Okay, an update for this thread. I got a gauge on the loader valve and bumped the main relief valve up by about 150psi. It was reaching 2000 so I bumped it up around 2150-2200.

The video that I link to below was taken before adjusting the relief valve. In the video you can't see the gauge face very clearly but it reaches about 1500-1700 psi when using the boom lift and then reaches 2000 when the ram reaches the end of its stroke.


The interesting (and exciting) thing about this video is that I can make the boom lift quickly and hold its position extended straight out if I jiggle the spool a few times before lifting?? This is the first time I have actually had to manually lower the boom from the extended position like that. Usually it just falls on its own, as you can see (listen for when the pump isn't working but the boom is still falling).

This proves to me that the boom rams are okay. Is that a reasonable inference? Is this my smoking gun to target the spools for repair?

Would it maybe just be some junk stuck on the secondary relief valve in the boom circuit??

Sorry the video isn't the best, I hadn't rehearsed it. I had actually just made the realization that this is happening. I had been working the hoe for probably 2 hours before this. I was not easily able to make this happen when I went back to the machine after it had cooled down, even after working it for a half hour or better. Maybe it is only possible when it is quite warm?

Please tell me your thoughts on the situation now knowing that with some finicking I can make the boom lift about 4x as fast and have it hold its position not bad.

https://www.youtube.com/watch?v=-y0T8Y3v1YI

 

[melben]

I would start by replacing the worn parts in the wobble stick assembly, the boom spool link looks like it is not moving in relation to the lever movement, A good check would be to disconnect the spool fom the control rod and work it manually, If it still drops in true spool centered condition t hen you have a hydraulic issue. With the linkage disconnected there should be no easy spool movement at center position. If there is I would remove the lower cap on the spool and look at the spring. I would also seriously look at that top shaft and bolt where the lever fastens but I beleive the spool is not being brought back to its center position, BUT that is not done by the lever it is a control valve function to keep the lever centered. The play at that upper bolt at the lever is causing the boom spool to not be stroked far enough to provide good flow through the spool.

Mel

 

[Operator4100]

Hey, like the other guy was saying, check the linkage first make sure the boom spool is going back to center, I think you have an issue with the boom valve body section, the engine shouldn't (strain) while booming down until you touch the ground and try to lift the back of the tractor somewhat, a cracked spool section will make them do all kinds of crazy things, let us know what you come up with, DW

 

[KevinF]

Thanks guys.

Is it possible that it is the boom lockout feature causing me troubles? It is a valve put in the boom hydraulic circuit and when activated it is supposed to restrict flow so that the boom cannot be lowered until ~3100psi (for more lifting capacity using the boom). There are no lables on the lever so I don't know if it is in the open or lock position but I have never noticed a difference in function between either position either!

I might try to bypass this boom lockout circuit to remove some variables from the situation.

Interesting note also about the engine straining when lowering the boom. I hadn't thought about that but it makes sense. Should be just like the stick when lowering aided by gravity. Cracked spool section.. Hopefully not!!

 

[Operator4100]

Good morning, yes the boom lock out is a variable that that needs checked out, a nice feature to have thou, try to plumb hoses around that to eliminate that possibility, DW

 

[KevinF]

Hi. I guess I haven't updated this in a while. I should do that so people with similar troubles can follow the troubleshooting process I took.

I bypassed the boom ram lockout and the problem persisted. I bypassed it by having a short run of hose made and capping the boom lockout hard lines.
Before:

After:


One day I was running the machine pretty hard and I noticed that if I jiggled the spool valve up and down I could actually make the boom lift with full power with no problem and it would stand straight out with no sag at all. More jiggling would cause the problem to revert back to the old no power, droopy situation. Here is that video if anyone is interested.
https://www.google.ca/url?sa=t&rct=...=dGRqo0bqAQH0Pan-f3h0Pg&bvm=bv.89947451,d.eXY

I ordered the o rings to rebuild the spool valves from TractorStuff and finally got around to pulling the control valve assembly on the weekend.

I took lots of pictures because I found the process hadn't been all that well documented on here before. My machine has the Case Cessna Valves with twin stick controls. The exploded diagrams are all available on casece.com in the parts store. The backhoe diagrams are all under the attachments folders, not under the tractor directories.

Here is the valve body I have. It is noted that the 580b service manual I have details the rebuild of the commercial valve, not the case valve, so I was only able to use it as a general reference.


Pull the aluminum caps off and pull the tie rods out. Unscrew and remove all the secondary relief valves. I kept everything in order and placed it on the bench as if the hoses were facing me and the valve block was right side up in the tractor.


These little things in the bottom of the picture are held in by their o-ring.


A 3/8 bolt with a little grinding is used to pull them out.

 

[KevinF]

Picks are mostly used to remove and replace the o-rings. A precision screwdriver was needed to be used as a chisel to lift these wipers out.


Replacing o-rings


Clean the SRV


This is a dissassembled relief valve. The process to get it apart can be a little bit of a pain and time consuming. I am finding that I am cleaning them first and sometimes need to use a socket with vice grips to turn the lock nut while holding the set screw with an allen key through the middle. The set screw uses a 1/8" allen key. Once the set screw is loose, remove the set screw. I am counting turns when removing the set screw. Then I found a screw with the same thread to push the cap out after removing the internal snapring. After that I use another socket to tap down on the piston which is sometimes a little stuck since water can get in past the snapring. After the piston is broken free you need to get it out.. Sometimes tapping with a brass punch through the tip of the relief valve works but don't shoot the piston and spring across your shop. Sometimes it can be worked out with a screwdriver. After it is apart, remove and clean everything and replace o-rings. Soak everything in hydraulic fluid for reassembly and be careful with the oring on the piston. Sometimes it is very tough to get back in as well. I sheared an o-ring twice doing it..

Upon reassembly, screw in the set screw the same number of turns. One RV is different (boom up) as it has a lower relief pressure and a restrictor dowel (I believe that is the intended purpose, it is outlined in the service manual) inside the spring. Make sure the plate under the snapring isn't spinning with the set screw when you screw it back in.. It will still be necessary to check/reset your relief pressures when done and running again.


This is as far as I am right now. I am hoping that changing all these o-rings and cleaning the secondary relief valves fixes my droopy lazy boom.

 

[KevinF]

I didn't realize I had already posted the video to this thread. It is the same video as I posted in post 6. Apologies.
Kevin

One day I was running the machine pretty hard and I noticed that if I jiggled the spool valve up and down I could actually make the boom lift with full power with no problem and it would stand straight out with no sag at all. More jiggling would cause the problem to revert back to the old no power, droopy situation. Here is that video if anyone is interested. . . .

 

[KevinF]

Got it back together. Works much much better. The boom is still a little droopy but it is actually usable now. I hope at least part of the remaining droopiness is just air in the lines as I only lifted the boom a couple of times before latching it and putting the tractor to work moving a parts car.

Even in the remaining droopiness doesn't go away, I would be happy with the way it is for a few years at least.

Here is the after video.
https://www.youtube.com/watch?v=aklrnJSYSWw

 

[AllDodge]

I see the problem,





It's not Yellow

 

[1968 Case 580CK]

Hey KevinF........Thanks for posting all those detailed pics! That really helps me as I am currently working on my 580 with the identical brake/differential set-up. I thought my differential was in crappy condition until I saw the pics of yours.....man, those teeth got a bit abused in the past. You did some amazingly great work. For me, I am not going as far as breaking the tractor in half, but am hoping I will solve the brake problems (check out some of my pics if you have time).

Hey.....since you tore into the manual tranny box, I have a question. My ole 580CK has the Hi/Lo range, and when going up grade or down grade and I lower engine rpm's, changing the amount of torque on the tranny, the Hi/Lo range sometimes pops into neutral, allowing the rig to go sailing downhill. (And not having working brakes, this is not a good feeling). You have any idea if there is a spring in the gearbox that holds the Hi/Lo in gear? There must be something to keep the gears from popping into neutral.

I also am about to attempt to rebuild the backhoe control box, as you did. All the advice you gave is excellent. I hope I can be as detail-oriented as you were.

Thanks.
dwight

 

[KevinF]

Hey 68 Case, sorry for the late reply, I get so busy with work and then I was away getting married, honeymooning, now back out on a construction site..

My machine does not have hi/lo and I am not familiar with them. Typically if a transmission or range box is popping out of gear it is a wear issue. Shifters do have detents in them and that should be all it takes to keep it in gear. The changing torque/switching from drive to coast side of the gears is changing the way the load is applied on the shaft on which the gears ride.. Your shaft may have excessive endplay due to a worn thrust surface or bearing. Not having been inside one, I can't help you any more than that! While not ideal, a well placed cam tie down down strap may save your butt.. It is better than free wheeling downhill in a 68 Case, that is for sure!

 

[1968 Case 580CK]

KevinF......hey, and congrats on all your recent activities....married, honeymooning, etc. I have been doing a seperate thread on how to repair the Hi/Lo range issue. Turns out it was a worn out Woodruff Key that was preventing a complete throw-action in the Hi/Low shaft. I took a ton of pics and detailed the process for whomever else may have to tackle it......talk about an extremely difficult gear cover to remove and reinstall, its a real head-banger if you dont know exactly what to do.

Just a quick pic of the Hi/Lo back together, and the fresh paint catching up on the rusty areas:

 

[melben]

The shift cap has detent balls and springs that engage those slots in the shift spools, the balls are in a drilling above the rail in the main cap casting. You may be able to add some tension to the spring to add additional spring tension.

I don't want to put a wet blanket over the shaft play deal but the detent ball locates the shift fork and collar in position and when the ball snaps in its groove the rail should stay put and the ball and spring will keep it there unless some pressure from gear or collar wear is overcoming the ball's holding capability. I hope you can correct it but if the gear and collar are worn you may have a difficult time holding it. Check the detent notches for wear on the Hi/Lo shift rail.

This was an issue (slipping out of Low range Lot ) when these machines were in their prime and I have had to split and replace worn parts to correct that very issue. Lo range slipout under down hill travel was the normal complaint.

 

[1968 Case 580CK]

The shift cap has detent balls and springs that engage those slots in the shift spools, the balls are in a drilling above the rail in the main cap casting. You may be able to add some tension to the spring to add additional spring tension.

I don't want to put a wet blanket over the shaft play deal but the detent ball locates the shift fork and collar in position and when the ball snaps in its groove the rail should stay put and the ball and spring will keep it there unless some pressure from gear or collar wear is overcoming the ball's holding capability. I hope you can correct it but if the gear and collar are worn you may have a difficult time holding it. Check the detent notches for wear on the Hi/Lo shift rail.

This was an issue (slipping out of Low range Lot ) when these machines were in their prime and I have had to split and replace worn parts to correct that very issue. Lo range slipout under down hill travel was the normal complaint.

Melben......Hello again, and thanks for the comments here. Regarding the Hi/Lo Range "shift cap".....the springs and balls seemed fine. Due to the wear in the small Woodruff Key, the Hi/Lo shift lever would travel 1-2" before the inside rail would begin to rotate. This applied in both directions.....going from Hi to Lo, or from Lo to Hi. So, it did not travel quite far enough to allow the balls to engage the slots. It was like only pushing the Hi/Lo lever part way. After I get all the new hydraulic hoses on, and some re-assembling, I will give her a try and see if there is still any popping-out of gear......keeping my fingers/toes crossed that this new woodruff key solved the problem. (I will update the thread once I am sure as to the outcome).

Interesting to hear that this was a common problem on these early 580s.