Komatsu PC50uu-1 hydraulic problem

OK, I tried this post in the main excavator forum and got no response. Maybe it should be here, instead?

I've got a 1993 Komatsu PC50UU-1 gray market machine. I've got the pdf manual for it. It's got a hydraulic problem that I've been unable to figure out.

This machine is a direct hydraulic machine, no electronics, solenoids, etc. in the hydraulic circuit. I believe it uses a gear pump. The pump is 3 stage and is supposedly brand new (installed by the previous owner). There are two...

Komatsu PC50uu-1 hydraulic problem

Komatsu PC50uu-1 hydraulic problem