Hydraulic lift pressure adjustment

[hayden]

I'm a real woose (sp?) when it comes to safety. Pushing something 10% is not very risky, and I'm glad I didn't even need to do that. At the rated pressure of ~2000psi, the chipper lifts up just fine.

 

[Pks]

Hi Peter,

Regarding the various fittings used to mount the pressure gauge; did you happen to notice if the fittings were metric?

I was in the process of adding a pressure gauge in the same spot you chose, but my fittings would not go onto the threaded male fitting on the valve. I could assemble the hose to my Tee fitting. But the Tee would not fit the port's fitting. It appeard the major thread diameter on the male fitting was significantly larger than what the Tee would allow. Yet the Tee could fit into the female hose fitting nicely.

Any thoughts?

 

[Pks]

Never mind. I figured out the differences. The hydraulic fittings are a hydraulic industry standard. I think it's called JCT. Mine are a size 6.

After installing the gauge, I could easily see that the loader relief valve was set low; about 1850 psi. So I raised it to the specified value (1979psi I think). Suddenly, the 3 pt is working better.

After playing a little bit, I noticed that I can even see the operating pressure in the 3 pt assembly when it lifts the box blade.

I wonder how many FELs are operating at a pressure lower than they ought?

With mine, the FEL relief valve would open when the load on the 3 pt got too large. That didn't make sense to me since my shop manual said the 3 pt had its own relief valve (supposidly set to 1979psi).

I figured that the FEL relief valve should open at a slightly higher value than the 3 pt valve. So mine are now set about 50 psi apart, with the FEL higher than the 3 pt.

 

[hayden]

You got it all right. Re fittings, hydraulics have at least 3 different standards for fittings, and they refer to them as #6, #8 etc. The ## is 1/16" so a #6 is 3/8" but..... it's more complicated that that. For example, #6 o-ring looks nothing like #6 NPT, and #6 JIC looks nothing like any other 3/8" anything. I fugure I'll understand it all just about when I don't need to know it anymore.

Re pressure setting, you are exactly correct. The lowest relief valve UPSTREAM from teh implement will release first. With the loader, the only updstream valve is on the loader control. With the 3PH, both the 3PH relief valve and the loader relief value are upstream, so the lowest setting will go first. That's what was happening with mine too - the loader was set low and was releasing first at something like 1600 lbs, which is way low. The loader should be a bit higher than the 3PH. My mechanic said 200lbs, which seems high to me. I like your 50lbs better.

 

[Pks]

Thanks to you and your posts! Your posts got me thinking and listening more carefully. I think we both learned something useful. Thanks.

My next step is to look at the 3pt pressure setting using the port under the seat. I suspect it will be slightly different than the value I can measure from the FEL valve location.