Pc160lc-7 komatsu when Hydraulics get to operating temp. unload pressure is getting high and pump is staying loaded. With all controls in neutral. Pressure is getting up to 2200psi controls in neutral Book shows max unload is 1000psi
Does the pressure goes down when u slightly make some hydraulic movement? Is it hard to start enginge when hyd very is hot? You should try to remove hyd LS hose near main pump and if then pressure disappears, im afraid your main hydraulic valve is wasted. LS hose is located on pump right side, i think it is only smallest one. How many hours does your Komatsu have? Normal neutral pressure should be about 30 Bar. Main hydraulic valve gives wrong information to hyd pump how much flow does it need.
Yes pressure goes down when slightly move swing handle. It has not been hard to start when Hydraulics oil is hot. Machine has little over 9,000 hours
Please try to check LS hose. Remove it, start the engine and watch what happens with unload pressure. Oil flow will be small. If pressure goes down then it could be failed main valve. Or u could try to adjust LS valve. As far as i know 160LC and 180LC weak spot is main hydraulic valve. Im not sure what exactly happens to it - cracks, scratches or it just wears out. But when it happens your only way to deal with it is buy new one. Komatsu dealer says it is not repairable. If you dont have problem with hot hyd engine start then you can just work with it for a while (1000+ hours) I bet hyd oil temp goes up when engine runs low idle and nothing moves...?
For starters, have you checked your fluid level and tank breather. Have you inspected your return filter for trash? Is your machine equipped with auxiliary hydraulics? Which pump is staying online? Front or rear?While ugis has given a solid suggestion with regard to unhooking the LS hose, why is LS being generated? Is it because a spool is off neutral, kinda gotta figure that out first. Do you have gauges and T-fittings to read pilot pressures?