bobcat 773 arm problem

[lucasto]

hi all, i have some problem with my BobCat 773 the lift arms have problem during the raising maneuver the arm raising very slowly; i have change the gasket and i have make a complete revision of the spool valve but the problem persists. How i can solve my problem?Thx

 

[OldMachinist]

Check to make sure the main relief valve pressure(3000 psi)set right. If it correct then it sounds like one or both the lift cylinders are bypassing internally(bad piston seal). If you can't get the recommended pressure by adjusting the relief valve then the ether the relief valve is bad or the hydraulic pump is getting weak.

 

[lucasto]

Check to make sure the main relief valve pressure(3000 psi)set right. If it correct then it sounds like one or both the lift cylinders are bypassing internally(bad piston seal). If you can't get the recommended pressure by adjusting the relief valve then the ether the relief valve is bad or the hydraulic pump is getting weak.

ok thx so much for your aswer. If you can help, I give u another information about my problem,when i do the lowering maneuver the arm move fast at the correct velocity. Another question where is the main relief valve near the filter?

 

[OldMachinist]

ok thx so much for your aswer. If you can help, I give u another information about my problem,when i do the lowering maneuver the arm move fast at the correct velocity. Another question where is the main relief valve near the filter?

The main relief valve is on the control valve. It's marked MR on the diagrams below. Its location depends on your serial number.

 

[lucasto]

The main relief valve is on the control valve. It's marked MR on the diagrams below. Its location depends on your serial number.

thx again for your prompt response; sorry but i worded the question wrong cause my bad English how i can test the main relief valve?i don't find, not the MR valve, but how to connect a manometer for ceck the pressure i don't find a test plug Thx again

 

[OldMachinist]

thx again for your prompt response; sorry but i worded the question wrong cause my bad English how i can test the main relief valve?i don't find, not the MR valve, but how to connect a manometer for ceck the pressure i don't find a test plug Thx again

Hook the gauge to the female coupler for the auxillary hydraulics.

 

[lucasto]

Hook the gauge to the female coupler for the auxillary hydraulics.

ok i have test the pressure and i have measured only 1000 psi even if I have set the main relif valve. It's possible a probelm of the pump?

 

[Tazza]

ok i have test the pressure and i have measured only 1000 psi even if I have set the main relif valve. It's possible a probelm of the pump?

It could be a weak pump or bad relief valve, even some crud stuck under the relief valve can do this. Remove it and check that the spring isn't broken.

 

[lucasto]

It could be a weak pump or bad relief valve, even some crud stuck under the relief valve can do this. Remove it and check that the spring isn't broken.

The problem is the pump i have disassembly it and during the check i have found the 2 worn and the gear nailed now i wait the parts for replacement. Thx at all Bye