Hi, I have a cat 426b that the rear stick control lever was getting difficult to move and finally just froze up. I pulled the spool out of the valve body (did not come out easy) cleaned the valve body (still on machine) and put spool back in but it is still binding. I am not very knowledgeable on how the spool centers and responds to center. Also looking for thoughts/ideas directions on what I can look for in the body that could be restricting the spool from moving. Or could it be the spool itself? thanks
Could be the spool. I would look at the grooves real good. If you see nice sharp 90 degree corners on the groves you are good. I would pull the valve bank and clean it all. sounds like you have debris in it.
The spool seems to have nice shape edges but does have some very faint scratches in it on two sides. Not deep enough to feel but can see them. About 1.5" long. I haven't removed the body from the machine yet and was kinda hoping wont have to as I work on this in the driveway. I cannot seem to locate a replacement spool on the cat parts website so I think I will have to make do with getting it to work.
Generally you can't buy spools without buying the valve body as well. They come in matched pairs. What may work is something like a Goddard's Silver Polishing Cloth. This type of cloth is impregnated with an abrasive often referred to as "jeweller's rouge". You can use the cloth to polish up the spool and take just a hair off the diameter. That should free things up, although it will be a long tedious process.
I cleaned the valve body (while still on machine) and the spool is still binding. Anyone know if I can hone out the valve body to make sure there is no obstructions stuck in there?
Why not? brake cylinder hone might go that small. Just make sure you wash it good with some spray cleaner before reassembly. Don't know about your machine but usually the spool has a spring on one end with a cup washer at either end of the spring. The washers slide on a sleeve, so the one spring will center the spool from movement in either direction.