Bob
These indeed do have surge brakes. The master cylinder is the same as that used on the M38 family of Jeeps, although the wheel cylinders are a little different. The wheel cylinders are the same used on the M101A2 and the Cdn Manac trailers. I had a quick look on the internet and the wheel cylinders are a standard brake cylinder used on civilian trailers, with a list price of around $20.
http://www.etrailer.com/Accessories-.../T0977600.html