Old School Brakes Help

I was just wondering if anyone out there knows about Hurst/Airheart brake calipers. I have a complete set, front and rear matching, from an old Grand National setup, late 70 vintage, that we had on a late model dirt tracker. Trying to revive them, and put them back in use on a 69 Camaro project of mine. The calipers need to be re-built/refurbished. I have the hubs, spindles, and a quickchange rear end that I am going to use, but no documentation for rebuilding the calipers. Any help would be appreciated.

I have never mess with them. Too exotic for my wallet. Cool stuff though. I did a little web searching and came up with this site. It may help you out.
http://rearenginekarts.com/h_a%20brake%20project.htm

Also Speedy Bill sells some of the stuff for a rebuild.
http://www.speedwaymotors.com/search-Airheart-brake.html

Hope some of that may help. Others here may be more informative about them.