a couple of questons, when the lift is staging improperly, if you run the lift to it's maximum length up, does it then start staging correctly? is it only in the lifting action that the sections travel improperly, or do you sometimes only have a problem lowering?

my instant guess is the seal in the center (first stage) lift cylinder on the piston is allowing bypass oil to get above the seal, (usually when just sitting and no weight or pressure is against the seal, so noticing this early in the day or ju8st after lunch?) and until the oil is forced back to the correct side of the seal by fully lifting.
The reason one set of cylinder lifts before the other set is not a valve it is called "mechanical advantage" that while the load is shared by all the cylinders, the center cylinders have an slightly easier time lifting is why they move up first, not some "cylinder lowering control valve" that controls the mast staging.
The valves you might see at the bottom of a lift cylinder are more likely to be what I call a velocity fuse, where if a lift hose were to break or other wise loose all pressure, the fuse would prevent full speed dropping of the load.
have someone else that the forklift tech you had look at it in the past, and get their price on repacking the center lift cylinder.


VerticalVicDude, I am not too sure your method of answering is all that clear or correct. you write;

Q//? I am thinking it's a valve sticking,(That's Correct)

I am not so sure it's correct...
and since to original post was dated 13 apr 2007, hopefully they got this fixed, and maybe will come back and let us all know what the problem really was...