Terex 860 Digger hydraulic fault.

[redcoo235]

Hi, have 2004 terex 860 with hydraulic fault. When only one service is activated on either the loader or digger there is very limited power, struggles to even lift wheels off the ground with the jacks. As soon as you activate another service full power is resumed, as in if you activate both jacks or 4in1 and main lift of loader everything works fine. Have tested the pump in both modes and both working fine and to full power as long as two service points are activated. Have stripped and check all solenoids to the clamps, breaker circuit and bucket quick attach and all working as should be so don't think they are interfering in oil flow.
Have checked for any crushed pipes or pinches but everything look fine. All main filters changed about 50 hours ago and up until now digger been working faultless. Digger was working hard digging rock at the time it happened so have a feeling it is some kind of relief vale that might have gone? Any help greatly appreciated.

Cheers, John

 

[davedb]

Sounds like some kind of check valve on the load sensing line is letting the pressure go? I could be way off as I’ve never done anything with these but it sounds like a load sensing problem to me

 

[nick...]

Could be a cracked slice in the valve block
Nick...

 

[Pheasant Surprise]

You need to run some pressure tests to find out what relief valve or component in the hydraulics is blowing off - hence your loss in power. Something is likely stuck/jammed or broken.