hitachi fh150lc hydraulic banging and pipe shaking (help)

[sid33]

Hitachi fiat FH150LC mark1 or 2 machine. was OK, new oil and return filter 30 hours ago
suddenly now has developed a worrying problem

when digging under load for example or even when arm in air and operate 2 rams to full extension and once at extenion, pump is making a bang noise and hose is shaking each time does this

See video below to show the problem (just copt and paste into your browswer)

https://www.youtube.com/watch?v=S0mekaApSDA&spfreload=10


operator with boom in air, jus moved dipper and bucket ram to full extension and then this happens.

once the problem starts, if we move the tracks, 1 track will not move after this noise.

if we move for example the Power / economy switch (for quick throttle change) then the tracks are then ok again

any advice or where to start

undo bleed screw on pump and oil flowing out so maybe not trapped air

any ideas

 

[mikebramel]

Could be major internal problem or could be oscillation of the pump unloading/loading. Check the pressure cut off in relation the main relief valve

 

[sid33]

you have idea where is pressure cut off / main relief valve is to try and check

 

[mikebramel]

If it's mechanical control, it would have pressure margin and cut off on top of the pump, it would be the bigger adjustments of the two. The Relief would be on the valve bank