PackardV8 wrote:
Wait a minute. I think i figured out how that ecihotrod system works:

Probably works like a two stage hydraulic jack. A fast low pressure circuit with slow high pressure circuit.

One piston piston moves the brake shoes real fast out against the drum until a cetain amount of pressure obtains. Then the sudden increase of resistence pressure causes a shuttle valve open to a much smaller piston allowing less foot pressure to create greater pressure in the line but over much less travel because the lost motion between shoes and drum has already been taken up by the fast circuit..

Just like a two stage hydraulic jack works.