O&K RH8.5 problem with hydraulics too slow

[Milos 123]

I have problem with hydraulics system on O&K RH 8.5, machine work well and pressures are good, but suddenly machine start to be too slow and pressures drop to around 200 bar, after I shut it down and start again it work well some time. But after problem back again and I need to shut down and start it again. Problem is probably with electric can someone help me to solve it ?
Regards,
Milos

 

[mikebramel]

Check the pilot pressure

 

[Milos 123]

It looks like electric problem, because when I shut down machine and start it again all is good some time. Is there proportional power valve on O&K RH8.5 ?

 

[Erik Iskopi]

Hello, I have a problem with the O&k8.5 in operation, it suddenly loses power and when I reduce the gas to a minimum and increase it again, everything is fine! Can you help?

 

[Milos 123]

Lose power of engine or ?

 

[Erik Iskopi]

The hydraulics lose power

 

[Milos 123]

Some problem with electricity, there is proportional valve that regulate displacement of hydraulic pump

 

[Erik Iskopi]

Do you know where that valve is located?

 

[Milos 123]

One hose from hydraulic pump follow and you will find... near engine

 

[Erik Iskopi]

Thanks

 

[Kjell]

The proportional valve is normally located behind the cab. Its in a block with several magnetic valves and an accumulator. The proportional valve is the one that is adjusteble from the underside. You measure the pressure from the proportional valve at the main pump at the measure nippel in the middle on the pump. I think you have a rpm related problem. It can be the engine losing rpm because lack of power or the rpm-sensor giving wrong value. This will cause the PMS system to regulate the pumps to achive the correct rated speed (rpm). If this is the case you will see this if you measure the pressure from the proportional valve. Pressure at idle 45 bar. Pressure when working in ECO somewhere around 20 bar( i dont have the exact value fot RH 8.5, only for RH 8). If the pressure in ECO rises when you lose hydraulic power it is because the PMS system regulates the pumps to avoid overload of engine.