You can get brake cylinder rebuild kits for those from Jim Carters Classic Truck Parts. Take your cylinder apart and as long as it isn't pitted up much, you can probably hone them and they will be fine. You may get differing opinions on the pumpkin gasket, but lots of people just say to clean both the cover and the differential very well and use rtv gasket sealer.
As far as steering, you can check the kingpins by jacking the wheel up just high enough to get a bar underneath the wheel and then lift it up and see if it moves much. If it's pretty tight your problem may not be the kingpins. The sloppy steering could also be the tie rod ends or the pitman arm adjustment, or the steering box.
Last edited by jgetti; 07/14/2008 4:35 AM.