CAT 320C low hydraulic power, engine stalling

Hi, Guys!

I have been having a lot of trouble with a CAT 320C Excavator (S/N BDE00683) with 16 000 hours on the clock, which my boss just bought. The excavator is well serviced, engine looks and works well, but when under load, the engine revs go down very fast, it stalls and there is no hydraulic power. I can excavate only with the tip of the bucket. If I try deeper, it stalls. It also happens with every other movement.

So with the help of some topics in this forum and a lot of reading...

CAT 320C low hydraulic power, engine stalling

CAT 320C low hydraulic power, engine stalling