Thanks for your help I will check this out.Just some more information to add, this is an intermitten problem the hydraulics work fine but ocassionally this occurs when I am lowering with a heavy load form a height, it seem to be lowering to fast with a heavy load,also my machine has regen- lowering and when lowering only sometimes it displays on the BDI that the regen is working correctly.Also when the regen-lowering is showing to be working correctly the mast lowering speed is reduced which seems to be correct procedure.Why does the the regen-lower not be constant when lowering?could this be connected to this fault?