Case 580B Main Relief Valve

Sudnurge · Sep 6, 2019

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?

Sudnurge · Sep 6, 2019

The loader control valve drawing above (many thanks to Alrman)shows the type of relief valve I have.

case480 · Feb 25, 2020

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?

Tinkerer · Feb 25, 2020

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.

Sudnurge · Feb 25, 2020

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.

case480 · Feb 25, 2020

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!

Coy Lancaster · Feb 25, 2020

Sudnurge said:
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.

What is your pressure at the loader control valve using the loader bucket rollback function?

Coy Lancaster · Feb 25, 2020

case480 said:
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!

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.

case480 · Feb 25, 2020

see what you think?

case480 · Feb 25, 2020

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.

Coy Lancaster · Feb 25, 2020

case480 said:
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.

case480 said:
see what you think?

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.

Sudnurge · Feb 26, 2020

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.

case480 · Feb 26, 2020

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!

Tinkerer · Feb 26, 2020

Is it this one ?
https://partstore.casece.com/us/par...0dc1c32&sl=EN&currency=#epc::mr52735ar1064596

case480 · Feb 26, 2020

Tinkerer said:
Is it this one ?
https://partstore.casece.com/us/par...0dc1c32&sl=EN&currency=#epc::mr52735ar1064596

View attachment 211629

Yes. Are thinking maybe spring #14 broken?

case480 · Feb 26, 2020

Sudnurge · Feb 27, 2020

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?

Coy Lancaster · Feb 27, 2020

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.

Tinkerer · Feb 27, 2020

Coy ;
If he gets the same results with bucket rolled back do you think he may need to replace the hydraulic pump ?

case480 · Feb 27, 2020

Case 580B Main Relief Valve

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