My dealer has been on phone with terex and they can't figure out whats going on . I have a hr-16 terex 8000 lb mini 1400 hours . All controls operate fine for 10 to 15 minutes then it gets jerky . when swinging boom side its a little noisy too . All controls still work , pressures stay right on where they should . Pump has been off and inspected and all good . They say I needed a relief valve got it , no different . Then check valve , got one , no different . Anybody with any suggestions please respond . Been at dealer 10 weeks
Pilot controls?
Any chance of inline counterbalance valves being contaminated? If they have them?
Not familar with the brand but sounds a bit like servo pressure to high or you have a restriction in the tank line may be from the servo/pilot levers back to tank when its getting warm . Has it got aux or breaker on the machine thats not stuck slightly open sticking pedal ect causing a flow divert. Possible crack in the servo maintenance valve when warm Also what is the condition of the hyd return filter any bits or blocked ect and has it got the right micron material as sometimes new machines come with a finer micron to collect debris from production until first service . Personally i would be putting/tapping in gauges in the pilot circuit in various places to see when it gets warm any thing changes may be places like before and after servo maintenance valve in the return circuit and get it hot an see if any thing changes. If its slew it could be cross line reliefs playing up on the motor if its got a slew brake this could be dragging.