Coy Lancaster
Senior Member
Have you tried adjusting the relief valve?
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Case 580sl Do these pressure readings mean I need a new pump?
- Thread starter Doug580l
- Start date
Doug580l
Senior Member
That sounds like a pretty complicated job, at least for me. Sure hope the new relief valve solves it.
Doug580l
Senior Member
No I haven't. Should I? Not knowing much about it, I was worried that I make things worse. The pressure does get up close to 3000 psi for a second or so when I dead head a cylinder. Then it quickly drops and holds at between 1750 and 2000 psi. Another thing that I noticed after cleaning the relief valve is that before cleaning it, at dead head the pressure would slowly drop from about 2000 psi to 1000 psi over 5 or 6 seconds sometimes. Now it drops and holds in about a second or so.
Coy Lancaster
Senior Member
Adjusting pressure is easily done by loosening the jam nut and turn allien screw in until pressure is correct.
If you get 3,000 PSI for a full second, then I wouldn't turn up the relief valve, you might get more trouble. That sounds like it's sticking, or operating slow. I'd replace the relief valve, or take the old one apart some more to see if anything is bent, broken, or gummed up with garbage. Nothing to lose if your alternative is to buy a new one anyway. Just mark the position of the nut and put it back the same way on assembly.
Your next step would be a flow test on the pump, or replace it instead of testing.
Your next step would be a flow test on the pump, or replace it instead of testing.
Tones
Senior Member
- Joined
- Mar 15, 2009
- Messages
- 3,083
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- Ex land clearing contractor, part-time retired
Doug, I was a bit hesitant at the start as it was a job i'd never done before but I had no other option. 2 main things are to have a very clean work space and a good memory. ;-)
Doug580l
Senior Member
That's what I was thinking. I have the new one ordered so hopefully that ends up being the problem. I have no way of doing a flow test so I might end up having to buy a new pump. The dealer wants over $1300.00 for one. What do you think about an aftermarket one like they have on ebay for about $750 or so?
Doug580l
Senior Member
The clean work space is doable, the good memory hasn't been around for several years.
If I do it, I will take lots and lots of pictures as I disassemble it.Doug580l
Senior Member
Thanks.
Coy Lancaster
Senior Member
You're welcome
Doug580l
Senior Member
Put the new relief valve in and it's about the same as the other one. When the fluid is still cold, it will get up to about 2800 psi.
With the fluid warm, not necessarily hot these are the readings I got. Loader bucket curled. Goes to and holds at about 1500 psi. Backhoe bucket curled, goes to approx. 2000 psi and over about 10 seconds drops and then holds at about 1000 psi. What now? New pump?
With the fluid warm, not necessarily hot these are the readings I got. Loader bucket curled. Goes to and holds at about 1500 psi. Backhoe bucket curled, goes to approx. 2000 psi and over about 10 seconds drops and then holds at about 1000 psi. What now? New pump?
That pressure dropping is funny. With the engine cold, try the backhoe bucket curled for ten seconds and shut off the engine with the bucket curl held still, then jump off and take the temps of the hydraulic pump, loader valve, and backhoe valve. That might show you the smoking gun, hopefully not literally.
The pressure reacting differently makes me think the loader valve is leaking worse, but I don't know how the "power beyond" is set up to make the loader and backhoe valves work together. That is the key at this point. Unless the pump is hot and the valves are both stone cold with that test, then it's the pump, but how do you explain the pressure difference?
Without doing a flow pressure test directly off the pump, we're guessing.
The pressure reacting differently makes me think the loader valve is leaking worse, but I don't know how the "power beyond" is set up to make the loader and backhoe valves work together. That is the key at this point. Unless the pump is hot and the valves are both stone cold with that test, then it's the pump, but how do you explain the pressure difference?
Without doing a flow pressure test directly off the pump, we're guessing.
Tones
Senior Member
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- Ex land clearing contractor, part-time retired
+1
The last sentence of Delmer's post is exactly what you should be doing or all you are doing is guessing and that cost's big buck's for no result. Isolate the pump and test. If it's good then move onto the control bank and pressure test every port. AND DON"T TOUCH ANY PRESSURE RELIEF VALVES until you now what the problem is and where.
The last sentence of Delmer's post is exactly what you should be doing or all you are doing is guessing and that cost's big buck's for no result. Isolate the pump and test. If it's good then move onto the control bank and pressure test every port. AND DON"T TOUCH ANY PRESSURE RELIEF VALVES until you now what the problem is and where.
Is the pump a gear type? If so, there's a simple way to confirm if it's any good. Dead head the pump outlet and attach a high range pressure gauge. Very briefly crank the engine (disable it from starting). If the pump is good it will immediately peg the gauge.
This doesn't apply if it's a piston pump.
This doesn't apply if it's a piston pump.
Coy Lancaster
Senior Member
The best way to find out is have a tech come out and preform a flowmeter test. This will take out all guess work cause all we'er doing here is poking a finger at problem.
Doug580l
Senior Member
Just performed the test that you suggested.
Pump. Temp before. 78 After 107
Loader valve. before 72 after 87 inlet valve and 77 outlet valve
BH valve before 74 after 74
Doug580l
Senior Member
I'm sure you are right. I will contact the dealer and see how much it will cost. Unfortunately I am over 60 miles form the dealer so it won't be cheap. I was being cheap when I bought the machine. It was about 90 miles from the dealer and I didn't want to pay what they wanted. Paying the price now.
Doug580l
Senior Member
Yes, it is a gear pump. So, if I remove the pipe coming from the outlet side of the pump at the inlet of the loader valve and cap it off, then I take the pressure reading at the test port?
Tinkerer
Senior Member
Wait until you install the new relief valve you have coming. You already said there was difference after you reinstalled it.When you have it out, crank the engine a couple of revolutions so anything lodged in the passage-way can be flushed out. Have you changed the hydraulic oil filter and inspected the pressure relief valve ? It is in the hydraulic tank.
I would advise you to do that while waiting for the new relief valve.
Last edited:
Doug580l
Senior Member
I did put the new relief valve in today and it is about the same as the old one. I'll take it off and crank the engine a little as you suggested.
I did change the hydraulic fluid and filter. How do i get to the relief valve in the tank? I looked at the parts book and don't see a relief valve being in the tank.