With the wet/dry selector it must be air brake. I had a 57 KW with the same selector, many early air brake three axle trucks had the ability to limit brake power for wet pavement before they started putting brakes on the steer axle.
Sounds like a really cool truck how about some pictures?


The difference between men and boys is the price of their toys.
Grant from Roy, Washington
1956 6100 Chevy Dump Truck in the Gallery
1964 GMC Drump Truck in the Gallery
user
http://s1301.photobucket.com/user/56Taskforce/slideshow/