If you take it to your local NAPA shop, they have a place they send them to over on the East coast that rebuilds them.
There's this outfit out of CA that does rebuilds and can bore out & resleeve your wheel cyclenders:
http://www.resleeve.com/booster.htm BSC parts stocks all kinds of parts for the boosters and I believe they do rebuilds as well. Can write to thier tech peoples and see what they say:
http://www.bscparts.com Not up on what a rebuilt unit runs for, but they are still manufactured new for use on some machinery like forklifts and can be easily adapted to fit an old bolt. It's a matter of finding the proper piston dimensions for your truck. What I found when I was looking for one, a new unit will run upwards of $400.
