its a exacavator type machine problem

[truecountry]

Mud Dog Vacuum Excavator 1200... i got a hydraulic pto driven pump and control valve and hydraulic motor driven pressure washer ...its a no dig site use water pressure to break up ground and vacuum the mud ...
its having hydraulic issue i think but also i cant rule out water pump
engage pto and engage water pressure its 250psi on hydraulic gauge and 2500psi on gauge for pressure washer hit the wand handle and it drops to 250psi on water side and everything on hydraulic and water pump chatters like hell till you release wand trigger
did a test tonite on pto pump 3500 psi at valve body ......the hydraulic motor was being tested but will not see that till monday any thoughts on this

 

[Delmer]

So this is a hydraulic motor driving a pressure washer pump? All the pressure washer pumps I've seen are three cylinder piston pumps, is that what this is? What kind of hydraulic motor driving it? and pump too.

First check the water pressure feeding the water pump. Then, the unloading valve is turning off the load when the trigger is off, and it's building enough pressure to unload, but not enough volume to work correctly. Either the motor is too slow, or the pressure washer pump is shot? or the coupling between them?

 

[John C.]

Kind of sounds like not enough supply to the water pump. Is there a suction strainer on the water tank?

 

[truecountry]

So this is a hydraulic motor driving a pressure washer pump? All the pressure washer pumps I've seen are three cylinder piston pumps, is that what this is? What kind of hydraulic motor driving it? and pump too.

First check the water pressure feeding the water pump. Then, the unloading valve is turning off the load when the trigger is off, and it's building enough pressure to unload, but not enough volume to work correctly. Either the motor is too slow, or the pressure washer pump is shot? or the coupling between them?

Its a Force brand pto pump ..parker control block ,parker hydraulic motor and coupling to water pressure pump...i been leaning towards unloader valve .....250 psi on control block is low to me to turn hydraulic motor
i sent the motor to hydraulic shop to check it over and got gauges to check pump now after checking pump pressure i have 3500 psi and gauge on control is 3000 thinking now valve was sticking..
water flow is good top pump and filter is clean

 

[Delmer]

Unloader valves are about as simple as you'll find, just take it apart if you think that's the issue.

Is the hydraulic motor a gear, vane, or piston? The 250 PSI might just mean there's no load on the motor and it's spinning easy.

 

[truecountry]

piston motor