This machine is a 1989. I've had it for 6 years now never had hydraulic issues, sure there not as quick as they once were but good and strong. Anyways the other day i was doing a job moving sand for a guy and the blade starts getting slow to pick up and then a little later on with any sort of material in front of the blade it didn't wanna pick up at all. id have to back up to get it to come up. I called CAT usually pretty good on giving me advice and they said could be hydraulic pump or control valves. Mechanic neighbor said hydraulic rams could be bypassing. The problem is how do i test the rams, the pump or the control valve no one really has great advice. When i put the blade down it will pick the machine off the ground so I'm kind of thinking its not the rams bypassing. All other blade tilt angles seem strong. Anyone got any advice?? TIA
It has a resolver system to signal the pump to stroke up when you need flow. There is dirt in it or a blown seal. Try to isolate the circuit that is the weakest and check that circuit's resolver. Also when trying to lift the weak circuit touch another circuit and see if it comes to life. Later Bob
Is the resolver located in the control valve?
Yes it is. If you want a description of how the system works and where the parts are located, drop me a PM with your machine Serial Number and your email address.
Anyway I could get that information as well please, having the same issue. 8RC s/n
i have fixed both of my d5h 4md and 8rc the seal on the resolver will not be there when you get in there ,resolver is in a alen head plug back of lift valve. the first ones was a white o ring the ones i got last year was red my advise is do lift and tilt you could tilt mine and make blade go up not something you could not live with till had time to fix.
nige why would they put seals in that high presser area any way.liked old way better more machine fit.