Hello I have a 2001cat 315C serial CJC05022 Excavator that barely moves. I started the machine, engaged the hydraulics and it snubbed the motor down while booming up until 3 to 5 seconds at full power and it seemed a valve released the hydraulics jumped and ran fine. Next day it did the same thing so I disengaged the the hydraulics a few times while running, it worked just fine after the initial start up and release at full power. Every time I shut the machine off it bogged for 3 to 5 seconds, then released and would release fine so long I didn't shut machine off. After 2 days now it barely moves. Ran test gauge on hydraulic ports and it's running 500 psi off the 2 main pumps and 0 at the hydraulic filters. Any help with this issue would be greatly appreciated.
Had a 9020B Case once with near the same problem about 20 years ago. Finally spent 500 bucks on a service manual. There were 2 or 3 little funny looking electric pieces that looked like sending units on an aluminum block in the pilot system in compartment behind the cab door. The book led me to them and sure enough when I touched one of them it was broken and fell in two pieces. Ordered a new one and it fixed it. They were only about as big as a grape. 2 different animals I know, but just throwing out an idea frommy experience. I think the one broken let pilot pressure tell the main pump when to stroke up.
Thank you Shop Dweller, any insite is always helpful. I'll have to look into a service manual.