For the last couple of years, this machine has had problems curling the bucket with it raised the whole way or while pushed into a pile. Recently, it now has trouble lifting the weight at all. I've seen people talking about seals in the valve block but everyone who verified that as their problem could get their bucket to raise if they used another function at the same time, but that doesn't work for me. Could those seals still be my problem? Also, the hydraulics on the rear of the machine work flawlessly. Thank you for reading and for any help.
I would test the hydraulic cylinders for internal leakage, first. Rule that out before messing with the resolver circuit.
If the boom is raised the whole way, it will stay in place for hours and maybe drift only a few inches. Does this rule the cylinders out?
No. Not definitively anyways. Cylinders will drift outwards, not inwards if the piston seals are bypassing. Its due to volume in each side of a cylinder. There is physically no room in the rod end to have the oil from the barrel end displace into it.
Bucket tilt is first in line after the steering resolver. Try curling the bucket whilst steering full lock.
That only verifies the boom cylinder pistons are not leaking and the valve that controls them is not leaking also. Resealing the bucket cylinder with OEM seals would be the first thing I would do. Doing so eliminates the possibility of it being the problem. IMHO.
Do not know how Cat does there valving but if the packing is bad in the cylinder and the pressure is equalizing across a leaky packing, if the bucket is rolled back with the engine shut off and the hydraulic lever pulled into rollback the rod end port should be open to return and piston packing leakage would allow the bucket to roll as rod end oil has a path to sump. My life has been with Case but I think there are probably similarities in operation.
Thank you for all of the information everyone. I wanted to try some of your suggestions today but I couldn't get the machine to act up with no weight in the bucket. I brought the machine home to try to fix it but I guess I need a pile to push into. Thanks again.
I have this same issue with my Case 580 SE. One of the tilt cylinders were leaking at the packing and unknowingly bought junk seals that had a split pressure ring. Before the new seals I could actually pick the back up off the ground almost. With new seals it will barely curl with a load of stone. Will be replacing the very soon. Again. I hate being a two timer on a job.