Hitachi ex35 slow hydraulic

[MasterofDiaster221]

I got a Hitachi ex35 excavator that got real slow on all the functions hard to even tell a difference between high and slow drive speed. I changed all hydraulic filters,pulled screen out of tank and cleaned it.Went ahead and changed fluid also change the pilot control filter, tank hydraulic filter and cleaned out the strainer bit no signs of trash. Put some gauges on the machine and dead headed each functions and all functions was at the 2800-3000 psi mark and pilots pressure around 450psi. Pulled case drain lines off the machine to check drive motors and there was just a drip in high and low.also checked my pressure when in high speed and was when petal was pressed pilot pressure was put to the line so all is good just wondering if the pressure could be normal but could flow be down?? Once the pumps slowed down the pumps started to whine

 

[mg2361]

Sounds like the pressures are a little low. I don't know the specs of an EX35 but I would venture to guess the pilot should be in the 500 - 700 psi range and the system pressure should be in the mid to upper 3's. A flow test would also be a good idea now too.

 

[MasterofDiaster221]

Not real sure on pressure I got to find a service manual to figure out what pressure need to be. But figured it was a pump issue since all functions where slow or a fluid flow issue it not pushing enough volume to work the functions at there best. Had a buddy borrow the machine and when it came back the hydraulic fluid level was over filled and the pump was whining horribly so that's why I changed all fluids and filters