2000 bobcat 334 operarating presure?

[melli]

Should also point out that you need a hydraulic tester...one that measures pressure and flow. From my manual, it says to record full flow at operating temps (Pump flow on a new piston pump is 5.23 gpm). Then slowly reduce pressure on a section by 100psi below spec (2500psi), and record flow. If high pressure flow is less than 80% of full flow, then pump repair is needed. Repeat for other pump sections...

The pump has a torque screw on side to adjust.
To adjust the hydraulic pump torque, loosen the lock nut
and turn the adjustment screw clockwise to increase pump torque.
counterclockwise to decrease pump torque.

 

[buster1]

well I bought the service manual pdf, took out the guess work . what I found out was that the no. 1 section of the pump no matter which of the relief valve settings pertinent to section no.1 are adjusted the pressure stayed the same. the relief valves for the other two sections would adjust up. some functions combine two sections of the pump that includes section 1 could not be adjusted was about 1/2 the pressure needed. looks like a new pump is in order.

 

[SSdoxie]

One failed section in a 3 section pump is very unlikely without seeing some efficiency loss in the other pumps. Unless you do a in-line flow at pressure check coming directly out of the pump (ahead of the 1st relief valves) to verify the pump is bad, I would not order/replace the pump, yet. Remove the relief valves associated with pump section 1 and inspect for worn/blown seal and signs of leakage around the poppet to valve seat. Some of these reliefs use a brass cup style poppet the spring pushes against, these poppets can wear down and leak by with age.

If you want, list the first 4 digits of your serial number and I can be sure I'm looking at same schematic.

 

[buster1]

well I was able to flow test pump and tested 8.6 perfect @ full flow . set relief pressure 2700 psi the pump reacted with a wooosh! after that the other main relief valves started working even a little high. very good no $2000 pump replacement...but arm still seams slow but has power now and swings slow 6 rpms not 9. not sure if valve are opening all the way or oil might be bypassing or left joy stick is malfunctioning or something else. thanks for all the help!