Excavator dozer blade relaxes slowly on its own.Will not maintain pressure on blade after a few minutes.Is the problem in the ram, in the control bank or elsewhere?????? Can someone please assist?
Is there any leakage from the rod end seal of the blade cylinder? If not, it's probably a small leak in the valve block. I have old tractors with similar problems with the 3 point hitch, though I just live with it and raise the implement every now and then. A leaking piston seal cannot cause cylinder drift by itself.
You can do a quick by-pass test, undo the 'raise' hose, fit a ball-valve and reconnect the hose. Raise the blade and shut the ball valve. If it still drops with the ball valve shut, it's leaking past the piston seal. If it stays up, the problems in the valve.
we've had the nut on the back of the packing in the cylinder somtimes would come lose and cause this problem
Thanks all for your assistance will try all suggestions and report back Regards