I was hoping someone with more knowledge than me might be able to point me in the right direction So the problem is no variable control on any of the joystick controls. This had started happening recently when it was cold started and then it went away within half an hour but now its back and not going anywhere. Its is a real jerk .. The pilot controls run off a servo pump, theres a pressure control valve and test point at the filter housing and then there is a distributer block of some kind - I think this just splits for both joysticks and has the the cab isolator solenoid but I dont really know, there is also a weird bell housing on the block and I don't know what thats for. So reading previous posts it sounded like servo pump failure/incorrect pressure were the most likely problem but I have pressure tested it today and it is at 600psi which is what the cat dealer specified. Any advice on what to check next?
Good day claranPT The pilot or servo pressure feeds the two remote control valves (Levers in the cabin) if these are not giving between 0 & 30-40 bars output it indicates that the plungers are sticking , suggest you lie the rubber boot and take a look to see if these are sticking. Checking the pilot pressure I have attached a info I hope it helps. Kind regards Uffex
I came across this in the files it may help you follow the valve, most if not all work on the same principle of spring pressure against surface area. Kind regards Uffex
Hi Uffex thanks for your response. Having spent today reading the hydraulics schematic and then doing some more pressure testing I have come to the conclusion that pressure comes into the joysticks at the right pressure and on all but one function goes out without mid level pressure (all or nothing) the actuators under the rubber boot on the joysticks are not visibly sticking so I will strip them down and see what I find.
Good day Claran Thats a strange fault some RCV have a filter on the pressure input port while pressure is good to the RCV it may be that this has blocked, if you have a circuit diagram it should show up. With full depression of the plunger the pressure should be almost the same as at the pilot pump. Is there any history of recent faults with the machine ? Kind regards Uffex
This attachment may help
Opps Missed a couple of details
Thanks for the extra info, it was as I started to suspect, the valves sticking. I think bronze from a bush that went blocked the main servo filter and biapassed it. A bit of emory cloth on the bore of the affected valve housings and it solved the problem.
Thanks for coming back Kind regards Uffex