I have a D4H and I have a problem with the lift on the blade. The machine has a reman hyd pump ( I have not checked pressures yet ) and this winter we put new bushings in the c frame pivot for coming up. If you have any dirt on the blade it raises very slowly. The blade will raise the tractor off of the ground while sitting still.
Huh? Are you saying when your sitting still, engine running, and not working any functions, the blade will raise the tractor off the ground???
Sorry, it was a long morning and I was very disgusted.:Banghead:Banghead No, the issue is the blade is very slow to raise up. It sometimes will not raise up out of the dirt when you are taking a 6" cut. The pump has been replaced and new bushings have been installed in the C frame pivot. The pump seems to produce adequate pressure I have not checked it with a guage, but you can put the blade down on the ground and it will lift the front of the dozer off of the ground when you want it to. Down action on the blade is fine, it only binds when trying to raise the blade.
OK, that's better. Now I can quit scratching my head. If you don't have issues with angle, tilt, or blade down pressure, then you don't have a pump problem. The D4H has a joystick control for the blade. What does the lever "feel like"? Has it got a clean/tight center neutral position, or is there a lot of slop in it? Does the lever have a good centering spring feel moving it in both directions? Is your linkage out of whack and the lever/linkage hits a stop before valve spool is all the way open? Just a few thoughts out of the gate.
The joystick has some slop in it. I didn't think about that not letting the spool completely seat. I will look at that and see. Thanks for the advice.
Have a helper pull the blade lever all the way back, or tie it off with a rope if your by yourself, then reach into the control valve area with a screwdriver or prybar and see if you can move the valve spool some more.
When it comes to hydraulics don't try troubleshooting without some concrete info. I would connect a pressure gauge(just t one in) that way you know exactly what is happening with the pump. If the pump is good you can move on to the valve. At this point it is a crapshoot until you eliminate the pump.
your pump works off a feed back from the valve. have had this problem on the 4 and 5 series usually in the control valve. there is usually a port plumbed out to the side of the compartment for checking this signal to the pump. it makes the pump stroke itself.