Was going to post a new thread, but found this one! Disassembled an old KR4200 from '89
The biggest issue was the casters kept falling off if it went over a small bump, or if I lifted the cart. Turns out the frame that the casters insert into were bent out of shape. 3D printed a square mandrel and found some aluminum off-cuts and a clamp and went to town. Back to square!


Emblem has seen better days. Quick paint and scrape and it looks fine from 5ft away:

The slides were pretty bad. Seized up so you had to force them open, and when you went too far, the hard stop was gone so they'd come out completely and ball bearings would fly. I called SO assuming they wouldn't carry new slides for a cart made in 1989, especially since the newer carts have increased in size, with longer drawers. I gave them the PN and to my surprise, they still keep new slides! Not sure if its used it any of the newer models, but was thrilled to hear it. They also sent new casters with the slides too!
Removed the aluminum drawer trims to get to the rust underneath. Quick sand and rattle can paint:
And here it is all put back together again. I was contemplating rattle canning the whole thing, but figured I'd leave the 'patina'. I did paint the bottom tray surface after sanding out some of the rust though.
Overall I had a lot of fun with this small project! Took a couple hours here and there, but finished it up in about a week. I really like these smaller carts for my home garage since they're easier to maneuver and I don't have a lot of room. The newer SO carts are great, but a bit too big for me. Exact same foot print as the KR488 cart (bottom tray is stamped KR488 actually).
Still on the fence about the piano hinge lid - I may add gas struts to it eventually to keep it vertical when opened.