LPU-5282 6600hrs. I havent been working on this machine yet, except for over the phone, but i'm told every cyl on thius machine started to drift badly at the sme time. If you put the boom out horizontal the bucket cyl drifts in retraction, the arm cyl drifts in extention, and the boom cyls drift in retraction to the piont were its all on the ground in a few mins. Also the blade cyl drifts down, or up when you pick the tracks off the ground. Also after 30 mins of opperation the boom losses power and won't pick a bucket of dirt out of the ground. Psi is 1900 on both pumps. Both port reliefs on the boom ciurcut have been replaced and both main releif valves have been replaced.
sounds to me like the pumps have give up and need rebuilt. any time the oil heats up a little and stops to function or gets really weak points you at the pump or oil that is full of fuel.
The hyd oil is new, AW46. The fillters have been removed, inspected, and replaced. No contamination was found. I have never heard of, nor do I know anything that can make all the cylenders start drifting sudenlly but that is the claim. The machine is about 250 miles away from me so i'm trying to think everthing before I have to go over there. The pressures in the arm and bucket stay good even when hot.
It sounds to me like the main coNtrol valve has cracked. One way to check would be to get it to your shop. Take the valve out then pressurize each cyl port with a press pump and look for oil escaping. if valve is good the port relief valves can be checked this way. Later Bob
Well I've never seen a hyd valve crack in a kobelco but that don't mean it can't happen. Thanks for the thought. wes
Did you check your pilot control valves? If it has a pattern change control, oil can internally leak through that. Im not sure if the 115 has it, but on the 135sr there is 2 pilot backpressure valves near the hydraulic tank, if they fail it can cause the hydraulics to drift. Can the machine hold itself up with the boom, or does it drift?