Relief valve question
- Thread starter Jimmyb33
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J_J
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- JACKSONVILLE, FL
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- Power-Trac 1445, KUBOTA B-9200HST
Sometimes, it sounds like a whine. Similar to power steering in your car when you turn to the extreme. What is causing this ,is all that pressure is trying to escape through a tiny orifice, and therefore the noise. If the relief were not there, and you had the power to turn the pump, you would probably exceed the pump case pressure, or the hose limits, or the cylinder or motor limits. What circuit are you talking about.
When the cylinders get to the end of their travel, you will hear it, etc.
Thanks for the info J_J. I am hearing the "whine" when using my front loader and am tring to lift something that is apparently too heavy or trying to dig out roots or stumps that aren't quite ready to come out. After almost two years, I am still learning the limits of the tractor / loader. I thought what I was hearing was the relief valve, but wanted to make sure it wasn't something else like the hydraulic pump or something. First tractor....
Jimmy
Jimmy
J_J
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- Sep 6, 2003
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- JACKSONVILLE, FL
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- Power-Trac 1445, KUBOTA B-9200HST
It is just a warning and a safety feature and is required to protect your system. Some of them can be adjusted, some are fixed.
The relief pressure should be checked every couple of 3-4 years. The pressure is dictated by a spring and as it ages it looses tension (like my belly!) and starts to let rip more and more easily (no comment!). A gauge is only about 20 bucks. 0-4000 psi is a good range. Typical is 2500 psi, but check the manual.
jb
jb
I'd been listening to my relief valve at the end of the cylinder travel for some time and suspected it wasn't set correctly as the FEL had a difficult time lifting the front on anything but a hard surface. Finally tweaked the relief valve when I got stuck last week in the muck and violla, front came right up. Trouble is, I adjusted too far and can hear the engine bog cause it's not relieving early enough.
Bought a 3000psi gage and brought it to work to check its accuracy. At first, it showed 25-50psi high. The more I "exercised" it up and down, the better it got. I finally reached a point where it was 10-15 lbs off.
Most of this type of instrumentation has a bourdon tube to turn the dial and are calibrated to be accurate at 50-75% of their full scale. I recommend running a brand new gage up and down 5-10 times before you take a reading. This is probably true if its been sitting for some time, too.
John Bud is right on about checking the relief valves. We check them annually on pneumatic systems. Not only do the springs weaken over time, the seats wear due to the chatter every time we make them work. It does this because at overpressure, the seat lifts just long enough to relieve the pressure and slams back down from the spring pressure, unless the pressure remains high enough to hold the valve open constantly. Still, repeated use over time causes the same problem as chatter.
Bought a 3000psi gage and brought it to work to check its accuracy. At first, it showed 25-50psi high. The more I "exercised" it up and down, the better it got. I finally reached a point where it was 10-15 lbs off.
Most of this type of instrumentation has a bourdon tube to turn the dial and are calibrated to be accurate at 50-75% of their full scale. I recommend running a brand new gage up and down 5-10 times before you take a reading. This is probably true if its been sitting for some time, too.
John Bud is right on about checking the relief valves. We check them annually on pneumatic systems. Not only do the springs weaken over time, the seats wear due to the chatter every time we make them work. It does this because at overpressure, the seat lifts just long enough to relieve the pressure and slams back down from the spring pressure, unless the pressure remains high enough to hold the valve open constantly. Still, repeated use over time causes the same problem as chatter.
JC-jetro
Elite Member
The picture below shows my tractor's main hydraulic relief pressure device. The spring tension causes about 2200 psi at some gpm when the pump is running. If I dead head the pump or cause a system restriction then additional pressure compresses the spring to the point the pointy valve will be pushed away from the opening orifice/seat causing the oil to dump. That opening and closing causes a strong pitched chattering noise associated with relief device.
JC,
