Komatsu pc 200-5 hydraulic pressure pulsation

[anwat]

Dear members,
Does anyone of you ever experience trouble with pc 200-5 main pump pressure pulsation,
I have tried anything from main pump suction hose replacement,accumulator replacement ,main relief valve replacement,main control valve overhaul and so on but those seemed to be useless.
Wish some hints and solutions to fix it
Thanks

 

[Hydraumind]

broken piston

 

[anwat]

The main pump had been checked for possible failure,there was no significant issue in the components inside

 

[Bls repair]

Does it happen with one operation or all?

 

[lantraxco]

Any noises associated with the pulsing?
Make sure the hydraulic tank is not overfull, might try putting about .5 bar air on the tank and see if the problem goes away.

 

[John C.]

A Dash 5 machine is pretty old now. It's likely the machine and the hydraulic system is worn out. You are going to have to provide more information as stated above. Does it only happen when one function is done or when any or all are moved? Has anyone put a set of gauges on the pump and checked the operating settings. You need to make sure the negative control, main relief, pump cutouts and TVC pressures are set to the proper specifications and then see if the surge still exists.

 

[anwat]

Dear friends,
I had tried to check the pressure parameter as directed by the shop manual,all seemed to be in range.
All seemed normal fom the engine start and continued with throttle up but when any handle was operated the pressure gauges began oscillating and even worse when relieving the main pump,this problem restored when i lower the engine speed to idle speed and it reoccured as the operation done as it.
Does anyone of you know what is the usuall reason that cause pulsation in hydraulic circuit?

 

[Bls repair]

Could a few things
1 ) control valve problem
2 )pilot control pressure
3 )relief valve

 

[anwat]

Yes,there could be either in those components.i will try to replace the control valve assy with the other unit to check if it solves the problem,as it is hard to locate the problem with conventional pressure diagnosting method.

 

[JJ960E]

does the machine mistrack ?

 

[anwat]

There was not any noticeable mistrack

 

[John C.]

I think you should check the hoses for being hooked up to the wrong connections. There are two hoses from each valve back going to each pump. Those are the jet sensor hoses and they handle negative and some of load sensing. You can have them hooked to the wrong valve or to the right valve but to the wrong connection. Once you have made sure those are correct you will need to check the pump control pressures. I stated what those were above.

 

[anwat]

Thank you friends for giving me some clues and ideas,
Yes,i think i had better carefully checked all the connections,sometimes we miss little but critical things during troubleshootings