HOW TO: Adjust the Pressure Relief Valve (PRV) on the MF GC 1705/10/15/20

[piercedtiger]

First of all, thank you all for an excellent writeup on how to adjust the pressure on the GC 1700 series. I have about a 7 year old GC2610 that I have owned for about 3 years. I have levelled about 1 acre of hilly land, rototilled the same, dug out hundreds of poplar tree stumps, and the machine is great.

Last week, moving about 3 tandem loads of dirt, I noticed the loader was straining to lift a full bucket. I remembered this thread, and went out and bought a 3500 psi pressure guage and tested my loader pressure, as per this thread. I had only about 1300 psi. The adjustment procedure was almost identical, but did not have the same bracket to remove (no 14 mm wrench needed). I was able to adjust the set screw through the opening for the mower deck height adjustment.

I increased the pressure with approximately 1/4 turns on the set screw, each adding about 200 psi, and fine tuned it to 1900, or very nearly the 1920 spec for the GC2610. I have not had a chance to give it a workout, but it surely must be better now, changing from 1300 to 1900 psi.

Thank you once again for an excellent writeup, complete with great pictures.

Jim

Awesome news! I just stumbled across this myself and assumed it would also work on my 6 yr old GC2600. I saw the set screw through the mower height adjustment and knew it would work, but it's good to read someone else actually doing it, and not having a bracket in the way!

 

[tjcooke]

great write up. I did this on mine, pretty simple to do. thanks for posting!

 

[Jaylegger]

It's been a long while since I checked the systems pressure on my GC2600. Thanks for the write-up, located the adjustment screw and there were no obstructions, had all tools in hand to tweak and you can imagine my disappointment when it still tested at 2100 psi. Pretty much the same as it did when new in 2009.

 

[Devi8]

I just ordered a gauge I'm curious to see what my pressure is at on my 2010

 

[Bavarian]

Nice write up.
I read only the first page of comments. Be careful on the pressure settings. Blowing a hose is not the end of the world. But going too high and blow a pump is going to be costly. Do not assume you can go higher than recommended on your xy model just because the neighbors yz model runs higher numbers.

Rule of thumb, a hydraulic pump with a aluminum housing can handle around 2000 Psi, a pump with a cast iron housing handles around 3000 Psi.
On most of the compact tractors, the pumps are aluminum, the cast iron pumps you'll find in the bigger farm tractors.

 

[rich1023]

New MF GC1710. Found issue of drift, or bleed down on both FEL and BH. I am installing wire fencing and the drop of the BH is considerable/visible with load. Would the pressure relief valve be the cause of the loss of pressure, resulting in the drop of the implements, weather the machine is running or not? With the BH off the 3pt also bleed down under load. Dealer claims the machine is within specs. I feel this condition (drift/bleed down) could be dangerous.

 

[Bavarian]

New MF GC1710. Found issue of drift, or bleed down on both FEL and BH. I am installing wire fencing and the drop of the BH is considerable/visible with load. Would the pressure relief valve be the cause of the loss of pressure, resulting in the drop of the implements, weather the machine is running or not? With the BH off the 3pt also bleed down under load. Dealer claims the machine is within specs. I feel this condition (drift/bleed down) could be dangerous.

Nope. Your drop has nothing to do with the pressure relief valve. It sits between pump and the first control valve in the hydraulic circuit to protect the pump. More likely you have internal leaks. It's just surprising that you encounter it on two different items.
Maybe they have the same level of quality that allow this drop. There is nothing to do if it's within the manufacturer's specs.

 

[coldsteelva]

New MF GC1710. Found issue of drift, or bleed down on both FEL and BH. I am installing wire fencing and the drop of the BH is considerable/visible with load. Would the pressure relief valve be the cause of the loss of pressure, resulting in the drop of the implements, weather the machine is running or not? With the BH off the 3pt also bleed down under load. Dealer claims the machine is within specs. I feel this condition (drift/bleed down) could be dangerous.

When off, all of the SCUTs will bleed down and slowly lower their FELs, 3PHs, BH booms and outriggers (if not pinned). While running, every implement, FEL, and BH should hold position regardless of load UNLESS there is a leak or damaged seal.

 

[rich1023]

Nope. Your drop has nothing to do with the pressure relief valve. It sits between pump and the first control valve in the hydraulic circuit to protect the pump. More likely you have internal leaks. It's just surprising that you encounter it on two different items.
Maybe they have the same level of quality that allow this drop. There is nothing to do if it's within the manufacturer's specs.

OK Thank You for that info.

 

[rich1023]

OK Thank You!