Case 350 - hydraulics drop from full height in less than 1 minute

[boggen]

you mentioned main relief valve was completely missing the poppet. and now you are blowing hyd lines....were is the missing piece? *shrugs*

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the blockage would be between pump, and relief valve on the valve. if blockage was after the relief valve, the relief valve would be going off. or less relief valve was not operating.

you have 4 lines
1 hyd line coming from pumps inlet (coming from hyd tank)
1 hyd line coming from pumps outlet
1 hyd line going to cylinder (cylinder end)
1 hyd line going to cylinder (rod end)

the hyd lines going to cylinder you can mix and match, and only thing that should happen is lever operates in opposite direction to extend / contract cylinder.

but the other 2 hyd lines, need to be in correct location. if you place pressure from (pumps outlet) to wrong hole on valve. pressure / hyd oil will not go were it is suppose to go. and may cause something to not operate correctly within the valve. example not allowing a one way check valve (pressure relief valve) to not to operate like it should. and actually keep the relief valve from opening up and forcing it to stay shut. which could have lead to you blowing the hyd hose.

not enough of hyd person to say what is what for the ports designations are..
BP, A, B, and other is T or C port? i know there is a reason why those letters show up on the valves vs saying inlet/outlet for pump, inlet/outlet for cylinders.

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ya i know ya already said it is almost impossible to get ports mixed up, but perhaps something above my "click" a light bulb on for ya.

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are you sure you were missing a poppet? and then started to put things in differently than what they should be? *been there done that* before.

 

[Godhungry777]

OK here's an update. I found the missing poppet. It had gone sideways and lodged itself in the rear of the block in the first port relief causing the above mentioned stalling/blockage. So I'm back to the original problem of the drop.
I lifted the bucket up about a foot and stuck it on a chock then disconnected the hoses from port A&B and plugged them. On removing the chock the bucket stayed solidly in position. So that rules out the cylinders and brings us back to the spool.
On taking the control valve around to a few places today, I'm looking at $2500 to replace it with an aftermarket sectional valve. The big expense seems to be in adding the four port reliefs and the detent float. I could get a monoblock for about half that but they don't come with port relief.

So question: How essential would you rate port relief? (I understand its role is to save the cylinders in the case of a shock to that circuit while the spool is in neutral. I'm just using it every few weeks to push dirt around on our property for a motocross track.)
While I am reasonably certain that it is a worn spool, I will follow up the possibility of the port relief on that spool not sealing properly.
If port relief is not essential, would this Prince unit from Surplus Centre do the trick (Surplus Center - 3 SPOOL 25 GPM JOYSTICK LOADER VALVE W/GRAPPLE

Still $600 plus adapters to get it here but that's a fair saving on what is available in Australia.

I'm taking a drive out to Toowoomba to go through a few tractor/rural wrecking yards tomorrow to see what might be available.

 

[J_J]

That valve should work.

Pump = 16.5 GPM, at 2200 psi.

 

[Godhungry777]

That valve should work.

Pump = 16.5 GPM, at 2200 psi.

Thanks JJ. What are your thoughts on not having individual port relief (secondary relief)?

 

[J_J]

A work port relief is used to relieve circuit pressure at less than the tractor system pressure.

They also provide spike protection.

 

[Godhungry777]

A work port relief is used to relieve circuit pressure at less than the tractor system pressure.

They also provide spike protection.

Yes but I can't see any port relief on the Prince valve (just main relief). Is that going to be a problem?

 

[J_J]

No, it is just extra protection.

You can always add an external relief valve for any hyd circuit.

If you use a stacked valve, you can get work port relief.

http://www.surpluscenter.com/item.asp?item=9SV-3-Y&catname=hydraulic

 

[Godhungry777]

I'm leaning toward three levers instead of a joystick+lever.

See any problems with me using this instead of the joystick one?

Surplus Center - 3 SPOOL 25 GPM PRINCE RD532GCCGAA5A4B1 OC VALVE
Still has detent float on first
25gpm, 2000psi (main relief 1500psi).
Is it the same valve block as the joystick?
Are the ports the same on both? The joystick says SAE 12 & 10 but the three lever says NPT 3/4" & 1/2"
Is there anything I'm missing?

Pros and cons of Joystick vs levers?

 

[Godhungry777]

I WON!!!
I pulled out all the check valves and port relief valves. One check valve had basically no orings left. Swapped the port relief valves around just in case it was the one on first spool that was leaking. Put it all back together and she's going up and down like a bewdy and staying up rock solid.

 

[J_J]

Pulling and checking the reliefs and check valves was recommend about 2 months ago, and I thought you had done all that.

Anyway, glad you got it fixed.