Hydraulic pressure question

[bazman82]

So I got a pressure gauge hooked up and I am testing the pressure on my ports on the farmtrac 785dtc. It is rated for 2500psi in the manual. The gauge reads 2100psi at PTO speed and with the lever still holding the pressure drops. I did some adjusting with the valve and after dropping it to 1500 it stayed steady. So I adjusted up to 2000 and it drops. I now have it at 1800 steady but cant go higher before it drops.

Would I need a new spring or relief valve? Hoping it's something simple..

 

[David88]

You take a quick connect, and neck it down with adapters or hose, to fit a pressure gage. 0-3000 gage. The attach it to the tractor connection and work the control lever and watch the pressure rise. Pressure sound be near 2000 psi. Use same lever you would use to lift implement.
I had farmtrac 330 hst and was similar problem.
I used a manual from reliable-store.com and it was very very helpful.. Someone told me it's technical but the manual had simpler ways for permanent fix

 

[bazman82]

That's basically what I already did for the testing part. I just cant seem to get it to stay steady past 1800 psi. When I adjust the relief valve for it to go over 1800 psi it will for a second then immediately go back down even though I am holding the lever still.

 

[bazman82]

Here is an example of what the pressure does. I was holding the lever at all times. The only time I let go was to let go and repull the lever and that's apparent when the pressure jumps up several times.

 

[bazman82]

I took part of the relief valve out but couldn't get it all out. Not sure if I need a special tool to get the other half out. I took out what I could and everything looked good and clean then put it all back and ran several tests.

 

[WranglerX]

If you can not get pressure high enough to operate relief valve (2500 PSI) I suggest you might have a tired pump or some other problem in system.... Just a thought....

Dale

 

[bazman82]

I am hoping it isn't the pump but the pump might actually be cheaper than some of the parts for the relief valve...I was looking at the workshop manual and it seems like it wouldn't be that hard to replace, just time consuming because having to take the left wheel and fender off to get to it.

If I adjust the valve to 1800 PSI then itll hold steady at that rating. If I try to go any higher by adjusting the valve, itll hit 2200 PSI but drop like it does in the video.

 

[bazman82]

I am trying to see if there is another relief valve between the pump and the auxiliary hydraulics relief valve but I am not entirely sure what I would be looking for so I am just looking for the wording of relief valve or pressure relief..

 

[mrmikey]

To tell for sure if you need a pump, you should actually do a pressure/flow test. You could have all the pressure you'd ever need but with no flow you aren't doing a thing........Mike

 

[bazman82]

To tell for sure if you need a pump, you should actually do a pressure/flow test. You could have all the pressure you'd ever need but with no flow you aren't doing a thing........Mike

I am fairly new with working with hydraulics as that I have never had this issue before so I am just trying to get things cleared up. I am assuming a flow test is different from a pressure test then?

The testing of the pressure that I did was at a rear port of the tractor. The lines that leave the rear distributor go to the 2 rear ports and to the loader from what I can see. So I figured testing it in a rear port would be no different than testing it at the loader control valve. Do I need to be testing it somewhere between the pump and the rear distributor?