Mahindra 4505 Hydraulics weak

smoky123 · Oct 25, 2012

Newbie to this sight,glad I found it. Looking to see if I'm right on testing the hydraulic pump, I have a Great Bend 330 loader on a 99 mahindra 4505 that started getting weak on the front and back on picking up hay. I have cleaned the suction filter and the screen in the spool controls with no help, no major leaks seen so I made up a flow through 3000 psi pressure gauge and hook it to the pressure side of the pump at high idle 250 psi, if I lift loader it goes to 600 psi, shouldn't it be like 1800 to 2400 psi.any help would be appreciated, I have a service manual but its not a great deal of help. THANKS in advance I think I need to rebuiild the pump.

J_J · Oct 25, 2012

If the loader was loaded, it might be a valid test, but just lifting an empty loader might not take much pressure to raise it.

A good indicator that the pump is not working correctly is if you hold the lever until the cyl is full extended and the relief pressure is acheived.

A better test would be to insert a flow meter, a pressure gage, relief valve assembly and a needle valve.

As you crank down on the needle valve, you will see the flow in GPM's, and the pressure.

If you can't get the pressure it means that the pump is bypassing, and need some work or replacing..

smoky123 · Oct 25, 2012

THANKS JJ I'll see if can get that set up to test and I'll add weight to it and test.

wdchyd · Oct 25, 2012

J_J said:
If the loader was loaded, it might be a valid test, but just lifting an empty loader might not take much pressure to raise it.

A good indicator that the pump is not working correctly is if you hold the lever until the cyl is full extended and the relief pressure is acheived.

A better test would be to insert a flow meter, a pressure gage, relief valve assembly and a needle valve.

As you crank down on the needle valve, you will see the flow in GPM's, and the pressure.

If you can't get the pressure it means that the pump is bypassing, and need some work or replacing..