312C CBA prefix 9600 hours Wondering if anyone has come across this issue, LH track motor does not have enough power to turn the machine, track starts to turn then stalls out. Machine tracks straight when using both tracks and machine turns normally on LH track when stalling out either stick or boom. LH track will spin if up in the air but not on the ground, starts to move then just stalls out Stall pressure is 2500psi when just using the track or 4300psi when stalling out another function. All other functions work well and are close enough to spec for ages and condition of machine. LH travel motor lines have been capped off at valve bank at it still only makes 2500psi until another function is activated. So travel motor and swivel joint are not the issue Pilot pressure to the spool is 230psi Travel straight valve works Negative control pressure on RH Pump is 550psi at high idle and no functions activated This then drops to only 500psi when using LH track Activate another function as well as LH track and it drops to 65psi If you activate a function on the LH pump then the RH negative control pressure jumps up to 630psi LH Pump negative control pressure is 650psi at high idle no functions activated 170psi with RH track stalled and if another function is activated with stalling the RH track it drops to 65psi If RH pump function is activated negative control pressure jumps to 700psi. Have run the machine with negative control lines capped and regulators up capped. No oil leakage from the regulator ports and if track function are used both go up to 4300psi and both work normally when used one at a time. Main control valve has been removed, stripped and inspected,no faults found so resealed and refitted. LH track still won't turn the machine. Main control valve is a 2 block design so hard to see down all the galleys but thinking there's a crack or issue somewhere that causes negative control pressure to not drop below 500psi. Other than LH track not turning the machine all other functions work well. Any thoughts would be appreciated
No replies yet.