Hey guys I have done some cut and paste from another forum. I need help. I'm about to loose my mind. I just replaced the lift and tilt spool seals on my 763. I spread 1 load of dirt. The pedals were working very smoothly. Then on the last bucket of material, the tilt spool was hard to push with my heel. When I got it to press down, it stuck. (kind of like detent) I had to return it to center with my toe. It is harder to push at higher rpm. No leaks. I put some cheap r and o hydraulic fluid in it to get it on the trailer originally. That fluid is still in the machine and its a little low but not too low and no cavitation/foaming. What gives? Why would it all of a sudden start acting up? New info about this. It is the tilt spool. I have tried everything! Filled up with fluid. I have narrowed it down to the centering spring, I think. I removed the interlock and tried it, still sticking. (btw, when i say sticking i mean, rough pedal operation and it sticks in the tilt up position, I have to rock the bucket a little forward to "unhang" the pedal. It makes it impossible to finesse the tilt) I turned the spool 180 degrees, still sticking. It seems that every time I remove the centering spring cap and re install it, the operation is just right for a short time (10 minutes) then it goes back to sticking and rough throughout the pedal range of motion. I put a little grease inside the cap which did nothing to help. There are no scars inside the cap like its been rubbed or anything. I can't figure this thing out! Any more ideas guys?
Sounds like you could have a cylinder going down and throwing crap in the spool.
have you disconnected the pedal from the spool to see if it's the pedal/linkage sticking or the spool itself? :drinkup
Not sure this would apply to your problem but one time I had a loader, actually believe it was a Michigan 175, that one of the spools in the valve body would work fine with no load on the system, say with engine off. However when trying to lift the bucket with a load where there was pressure in the system it would get very hard to move. Pulled the spool out of the valve body and found it to have a crack part way through it. When under pressure the spool would flex and bind in the bore. It's been many years so I don't recall if we located a used valve assembly or just a good used spool. I know spools are "matched" to the bodies when they are made but this old machine would not have been worth the cost of a complete valve body at the time so we very well might have just stuck in what ever we could find cheap.
mtnride : You stated that you re-sealed the spools ..... did you by any chance have any crap still inside of the valve bank ?? ... like a broke piece of seal .... it'll float around in there..... cause if you did once the hyd pressure builds up you'll find it near to impossible to make it shift ....... check it out .... good-luck