I have a 580B, circa 1975, and the hydraulic system has become weak. Stabilizers won't lift tractor, but will hold it up if I lift with the boom and extend them. Other functions (dipper, bucket) don't have much power. I suspect the main relief valve, but I don't even know where it is located. My rig has the Cessna valve assembly. Any ideas?
Welcome to HEF @Sudnurge The main relief valve is located at the loader control valve. The parts listing only shows a Parker valve, so I'm guessing you have a Cessna backhoe control valve. I have included a pic of the 2 spool & 3 spool types. - can you confirm this is correct? The main reliefs are marked with the red circles & the power beyond fitting is in green. The power beyond should be checked as this sends pressure to the backhoe valve & if the internal orings are blown the backhoe will have significantly less pressure than the loader. You should really only attempt adjusting the main relief with the use of a test gauge - or you can cause more expense with damage to components.
How is the front loader functioning is it slow also?
Thanks for the help. The front loader seems to be working ok. When I max out one of the backhoe functions, e.g. The dipper, I can hear what sounds like a relief valve singing, although the stalled function has not produced expected force.
The loader valve set is the two-spool picture you sent airman.
More than likely the power beyond oring is bad. I believe Altman circled it in green. The hyd. line going back to backhoe is attached to it. Remove line then fitting and replace all orings.
Power beyond o-ring was bad. Replaced and no change to power issue. Removed relief valve to check for debris but did not tinker with adjustment. O-ring on relief looked ok so I left it. Reassembled and still have weak backhoe.
When you bottom out a backhoe function does another function try to work?
Check the hydraulic pump output pressure. Should be 2200 psi at the main relief valve. You did change the hydraulic filter didn't you ??
Filter has been replaced. Waiting for delivery of a gauge set to check pressures. Cannot see another function trying to engage when I max one out. This issue came up rather quickly vs a gradual loss of power. Seems to be a fairly consistent amount of power still present, i.e. the stabilizer only lifts the tractor about an inch - not completely off the ground - each time.
I use an oxygen gauge, the ones that are used on a cutting torch regulator. I use a grease gun hose on it and hd pipe fittings. The gauge never ever be used for oxygen again.
Can anyone recollect whether or nor the internal o-ring on the power beyond valve is supposed to have a backup ring? When I took off the old one, it did not, but I have seen plastic rings completely disentegrate in other places, i.e. load check poppets.
Following. I have similar symptoms and will be tackling this soon. Repacked every cylinder on the machine except the hydra leveling, basically 100% of the fluid has been changed including what’s in the cylinders, new filter, no luck. Certain backhoe functions lack some power but not all. I do get a small amount of ghosting if I hit the different controls just right but it’s rare. Hoping it’s the main relief or power beyond. Taking out the backhoe control valve doesn’t seem very fun.
Pressure with a function (stabilizer) bottomed out is around 1200 psi at the test port on loader valve. Reading no pressure at all with no function(s) engaged. Tweaked main relief valve to try and increase pressure but no change. I'm guessing pump at this point. Any other ideas? Brand name is Danfoss. Are there other manufacturers pumps that will replace it?
https://www.ebay.com/sch/i.html?_from=R40&_nkw=Case+580B+hydraulic+pump&_sacat=0&_sop=16
You shouldn't discount that you may have a problem with the main relief valve. I have seen similar symptoms in the past, with adjustments not making any difference to pressure. Those valves would have issues with worn poppets & seats - these were able to be replaced as a spare part. Unfortunately, you need to replace the valve to be sure it was the problem & not the pump. The pump should be flow tested to confirm it's efficiency - this may be easier to do than replacing the valve...... or swapping one from another machine. It would be a shame to buy a new pump & fit it & then still have the same problem.
I removed the relief valve and disassembled it to check for debris or a broken spring, etc. and could not see a problem. The needle had a shiny ring around it where it contacts the seat, but no deformity. Had a job to do with the hoe, so I started digging at reduced power, but within a few minutes, the thing started losing more power until after a half hour, it was too weak to lift an empty bucket. I went ahead and ordered a pump. Hoping that's the problem.
When you install new pump be sure and back off main relief valve before starting machine. The new pump could be damaged if main relief was adjusted to increase pressure with old pump.
Got the new pump; installed it and backed the relief valve off per Coy's advice, and got it working. Set the relief at 2100 psi, and she's back to life! Thanks for all the good info, Coy, Tinkerer, and Alrman. Glad I joined up with you guys.
Glad everything worked out and you are going again.
Now I have run into another issue. The main relief valve is erratic. There appears to be a score on the poppet where it contacts the seat and I don't think it is uniform around the poppet, so sometimes it seats sufficiently and if it rotates during operation, it seems to bypass. This is of course conjecture, but the system pressure sits at 1100 to 1200 psi, then if I hold a motion maxed out, it will stay there and then start pulsating and then suddenly jump to whatever pressure is dialed in on the relief. Does anyone have an idea where I can get a rebuild kit for the relief valve, or a new one? Or even a used one I might be able to have machined if needed?
The loader control valve drawing above (many thanks to Alrman)shows the type of relief valve I have.
sudnurge, I have a 480B that is the same symptoms. It is weak in all functions. I put a new pump on it about 20 hrs ago. after reading this, I am going to check the orings this weekend. what did you separate to insert the pressure gauge? did you get yours fixed?
Welcome to HEF Case480 ! sudnurge hasn't been on HEF since last September. You won't likely get a response from him here. You can try starting a conversation (PM) with him. HEF will send a notification in an email to him.
Thanks for your query 480b. My rig hasn't had full power for a while. I disassembled the main relief valve and replaced all orings and the relief valve pilot poppet. Took out the power beyond valve and inspected it for cracks and put new orings in it. Rebuilt all secondaries and load checks throughout the system. It will hold around 1100 to 1200 psi with a motion engaged and bottomed out. If I hold the motion (I use the right hand stabilizer in the fully retracted position) for a few minutes, the pressure will begin to pulse very high, but will surge repetitively and not stay high. I have the relief valve set to where the surges won't go over 2500 psi, but it's almost like there's a continuous fluid bypass somewhere in the system and even tho it's bypassing, the pump can catch up with after a while, but not enuf fluid volume to maintain adequate pressure. The port I use for the pressure gauge is on the outboard side of the loader control valve assembly.
ok. I have the same port. i got a gauge today. I am going to try to post some pictures of the relieve valve. tell me what you think. I only see one oring. thank you for responding. Like Tinker said, it was a long shot, but you answered!
What is your pressure at the loader control valve using the loader bucket rollback function?
Check your pressure at loader control valve using the loader rollback function and see what you have and then check the backhoe function using the stabilizer.
see what you think?
Coy, I have not put a gauge on it. I can do that this evening. All hydraulics are weak. gets worse as i use it. Will pick a scoop of dirt in FEL up about 2'. i dug a hole with the hoe last week, it would not hardly pick the hoe up out of the hole after about 20 min. I replaced the pump in September of 19. it has about 20 hours on it.
The valve you showed doesn't look like the main relief valve, it looks more like a circuit relief valve. Also see if you can find the model and serial number tag on loader frame.
I guess the 480 and 580 relief valves are different - near the top of this thread, Alrman included some diagrams of the 2 and 3 spool loader valves. The arrangement on the 2-spool drawing is what I have on my 580b. The relief valve is in the section immediately to the right of the outboard spool, and has several components that must be accessed from both the front and back of the loader control valve block. There are two separate springs - one inside the pilot cartridge, (the first component that comes out from the rear side) and a main relief spring further inside the relief valve cavity. If either of these springs is broken, the relief valve will not allow the system to load pressure. There are a few orings in the assembly that have to seal as well. Attached is an exploded view of the relief valve like the one on my 580b. Hope this helps.
Coy, I will get the number off the loader. Probably tomorrow. Sudnurge, that control body looks similar, but not the same. The valve in the pictures came from that spot you and arman posted. There was no access on the back side. I am going to out it all back together, then put a gauge on it. That will maybe direct us somewhere else. Thank you for the input!
Is it this one ? https://partstore.casece.com/us/par...0dc1c32&sl=EN¤cy=#epc::mr52735ar1064596
Yes. Are thinking maybe spring #14 broken?
Coy in response to your question at 27 above, (I'm assuming it was directed to me), I'm sure I have tested pressure with every function maxxed out and get the same results, but just to be sure, when the weather dries out here, I'll go out and get a reading on the loader rollback. If I get different results, what will that tell me?
That will tell you that your problem is between the loader valve and backhoe valve. I would check your quick couplers on hoses going to bh valve.
Coy ; If he gets the same results with bucket rolled back do you think he may need to replace the hydraulic pump ?
I was thinking he replaced it already but if it was replaced and the main relief was not reset then it could have damaged the pump. A flowmeter is really the only way to test the pump without disassembling it.
It is a new pump, but I had backed all the way off the relief valve before I cranked it. One of you guys gave me a heads up to be sure and do that. No quick connects on the supply line from loader valve to backhoe controls. Tried the rollback both directions, same result - as I slowly engage the control valve with the motion bottomed out, the pressure climbs to around 12 or 1300 psi, and just lets go - all the way to near zero psi and then starts that surging. Same as it does with the downstream backhoe hydraulics.
I took the valve out the backside. Poppet, spring, and valve body. Everything looked good to me. I reassembled both valve bodies. Started it up. Let it warm up 10 min, with pressure gauge in port of loader valve. Started curling, and holding the FEL bucket in backward position. 1200psi. Over and over. Then, like something broke free in there while holding the curled buckled, motor labored hard, 2400psi. I let off, pulled outrigger all the way up and held, 2400psi. Took it for a test dig. I have owned the hoe 2 years. Never before would it pick the entire back end clear of the ground. It does now! The hoe itself is stronger than ever before. Is 2400psi too much? Did I accidently turn some pressure up? I guess one of those valves was stuck, and by me disassembling, it freed up. What do you guys think?
I think I read somewhere that the operating pressure should be around 2200 psi, but I'm not sure and while 2400 probably won't damage anything, it might reduce the life of your hoses. But that is just speculation on my part. Glad to hear your pressure is back!
From the service manual. 2200 psi + or - 25 psi at the main relief valve, full throttle.
Tinker, 2200 is what i thought too. I would just assume turn it down to within specks. I dont have a need for power/over faster wear. it is just on the farm. can you tell me where that pressure control is? thank you for everyone's help.
Case, you inspired me with your success story; the weather was nice yesterday (after a nasty night of thunderstorms) so I plucked up the courage to tackle my old rig again. Pulled the relief valve apart one more time, polished everything, cleaned and reassembled it and it started off with the usual low pressure and surging, but I started playing with the bucket lift because the spool didn't look like it was returning to proper center, and viola! Darn thing started working perfect! Relief valve was a bit high, so I tweaked it down to 2200 and I guess that bucket lift spindle out of position was allowing the fluid bypass, preventing the pump from being able to generate adequate pressure. If your relief valve is adjustable, the adjustment should be item 2 on the drawing Tinkerer sent you. But on the parts list accompanying the drawing, it says 1500 psi spring in the relief valve. Not sure what that means, but It could be your valve may not be adjustable, and it may require different springs to obtain different pressures. Anybody?
Case, you inspired me with your success story; the weather was nice yesterday (after a nasty night of thunderstorms) so I plucked up the courage to tackle my old rig again. Pulled the relief valve apart one more time, polished everything, cleaned and reassembled it and it started off with the usual low pressure and surging, but I started playing with the bucket lift because the spool didn't look like it was returning to proper center, and viola! Darn thing started working perfect! Relief valve was a bit high, so I tweaked it down to 2200 and I guess that bucket lift spindle was allowing the fluid bypass, preventing the pump from being able to generate adequate pressure.
Sorry for double post - not quite sure how that happened...
isnt it nice when they all the sudden start working! Just a Customer Service note. Back in September I bout a new pump from Brokentractor.com. Last Monday i sent him an email explaining my problem. very confident it was the pump, and I was hoping i would have maybe a 6 month warranty. This was at 4:30PM. At 4:40, my phone is ringing. It was Ken, he wanted to go over a few things to check. I had already done those. He said he was going to check with another guy in the shop in the morning, and call me back. 8:25am, he calls me back. they believe it is the pump. He said I will get you a new one in the mail today. he also printed off a UPS slip to ship the old one back to him. he said no hurry, just did not want me waiting on a new pump. All this to say, Customer Service like this is hard to find. I have not paid a dollar for the new pump. I am shipping his new pump back to him.
my relief valve does not seem to be adjustable. I mean by that, there is not a set set to lock into any one position. it appears, tighten until oring is snug, end. Is this correct? If you have an adjustable one, would you post a picture. does it look like mine in post 36?
Attached is a pic of the relief valve adjustment on my 580b. No yours doesn't look like its adjustable, but I don't know. Maybe Coy or Tinkerer can help you there, but since the parts list for your relief specifically calls out a 1500 psi spring, it looks to me like there may be different springs for different pressures. Could also mean that 1500 psi is the minimum pressure your relief valve will allow. There's a guy named Dale Weissman in Indiana who runs an equipment salvage business, Tractorstuff, sells new parts and has contacts who help him locate parts. He is as knowledgeable on these backhoes and their hydraulics as anybody I've dealt with. And he seems to really want to help you, rather than just try to sell you something. You might also give him a call, as the pressure you're running seems a bit high.
update. I have used the hoe about 3 different times now. each time, the first time of the day, when i set the outriggers down, 1100 psi. I have to hold the lever forward for about 5 seconds, then something opens up all the sudden, the motor loads up, 2400 psi, and full power to all the hydraulics for the rest of the working period. my guess is, one of those springs is bad, or one of those poppet valves is sticking. thoughts?
Have a case poclain 788 1997 that loses all power after about 20 30 min running time spend 5 grand on ignorant specialists stealing my money instead of fixing it, nobody talked about any valves only the usual pump is bad, spend 20 grand to fix it bs talk
You probably want to start a thread in the excavator section so we can help you better, no use in tagging on to this one. Please include the S/N and type of hydraulic pump because there was a change over later on.
Just information in the future that someone might be reading this. The problem seems to be fixed at this point. It has been the pump causing problems the whole time. I have now put 3 pumps on. we think we got it fixed now. the O rings inside the pumps were just dissolving away. finally the pump manufactured offered a recall on that run of pumps. they sent me new Orings. i put them in, and no more problems.
My advice to anyone having pump issues is don't cheap out on the pump...Was having all the same issues with a 580C and purchased new ebay pump for $369 bucks, worked great for about a month then starting losing pressure, repeated all the same steps, power beyond, pressure relief, rebuilt backhoe control, loader control, etc...Where's the pressure going???? Installed a new front seal in the oem Cessna pump and installed just to test system, turns out that cheap ebay pump was not such a good deal...Ordered a pump from the dealer,at the time Coleman equipment that was still in business, cost about $600 and haven't had an issue since...
That is the only one for the system
Check post #2 of this thread. Pretty self explanatory, pictures and everything. Are you inquiring about 580C? What are your issues? With the machine I mean.