Relief valve

   / Relief valve #1  
G

gearhead1

Member
Joined
Dec 21, 2006
Messages
25
Location
NC
Tractor
Kubota B6000
My FEL (just bought a used tractor) wouldn't lift an engine block, nor would it lift a bucket half full of dirt, so I put a guage on the inlet side of the valve assembly. I was only getting 800psi. I adjusted the relief valve, but I can only get about 1100 psi out of it now. If I adjust (tighten) any further, it pops back out almost like it is stripped or something. When I took the relief valve all the way out, with the adjusting nut loose, it seems to hold and thread properly when it is near the low pressure end (threaded out). If I turn it near the high pressure setting (threaded in) it gets to a point, slips, then I can move it in an out about an 1/8".

I looked online, but couldn't find anything exactly like this relief valve, maybe I was looking in the wrong place or do I just need to buy a new loader valve assembly?
 

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   / Relief valve #2  
The same thing happened to me this year. I also installed a pressure gauge to determine what I had. I could just barely lift the bucket empty. Upon examining the relief valve I found a small piece of rubber debris in the seat. Once that was removed everything worked as usual. By the way, that relief valve was made by 'Sun', probably in the late eighties. When I called them for a replacement they couldn't even find a cross reference number for it. Don't know what I'll do when the valve assembly goes. Probably replace everything with a 3 spool valve with power beyond.

Doug
 
   / Relief valve
  • Thread Starter
#3  
Interesting......I'll look for debris as well. Did the adjustment seem like it quit turning, as if it was stripped?
 
   / Relief valve #4  
Gearhead, since your threads seem to be OK when the RV is
screwed out, consider replacing your spring with a longer and/
or stiffer one. Experiment with different setups.
 
   / Relief valve #5  
It sounds as if you are screwing in the threaded portion till it drops off of the threads on the outer portion. You could try a stiffer/longer spring, but then I would be asking the question, how much pressure is this valve rated to deal with. IE, does it have an 1100 PSI limit for a reason? Can you locate the manufacturer and a model number to perhaps find the original valve specs? Most general use hydraulic equipment these days has 2500-3000 PSI rating. But look at some of the stuff on the Surplus Center website. You still find cylinders and valves with 1200-1500 PSI ratings... And if this valve is on there, what are the specs for the rest of the system?

If I couldn't find the specs for the valve, I would be tempted to replace it with a newer valve with known specifications.
 
   / Relief valve #6  
gearhead1 said:
so I put a guage on the inlet side of the valve assembly. I was only getting 800psi. I adjusted the relief valve, but I can only get about 1100 psi out of it now.
Click to expand...

When you hooked up the gauge, where you operating a function to "deadhead" the system?
Or where you just reading the pressure while nothing was being operated?
 
   / Relief valve
  • Thread Starter
#7  
RonMar, I went to a hydraulics shop yesterday, it is a Gresen valve. They said it is good for 3000 psi or so. I have a Vickers vane pump, and they said those are good for 2000psi continuous, 2500 intermittent. I took the relief valve with me and they said it was wore out.....So I got a new one I am going to try today.

KennyD, yes I was dead-heading the system by curling the bucket. Good question - you can't assume anything when troubleshooting!!
 
   / Relief valve
  • Thread Starter
#8  
I put in the new relief valve, set it to 2000psi, and it works great!!!

Thanks for the input from everyone!!!
 
   / Relief valve #9  
Glad to hear you got it working:D
 
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