1) Power brake bleeders can offer a lot of pressure and should be operated by a professional brake man that knows the correct pressure for your system. The basic system (air over fluid) operates with a head of adjustable air pressure on the tank, which is filled with brake fluid. The air line from the tank is connected to a special cover that can be tightened to the master cylinder. This provides pressurized fluid to the system.
3) These combination valves (above) have been cut away so you can see the contain a proportioning valve, a metering valve, and a differential warning switch to alert the driver there is unequal pressure in the brake system. They have been on most American cars since the late Sixties and are a good replacement for the aftermarket manual proportioning valves.
4) Vacuum bleeding is done (right) at each wheel cylinder or caliper by applying 17 to 20 inches of vacuum at each bleeder. This is the equivalent to about 10psi. When bleeding calipers always have to remove the caliper form the bracket and use a piece of wood to hold the piston, in place of the rotor. The Mityvac bleeder is being used her to bleed a caliper. Simply pump the handle until 17 inches of vacuum is reached. A number of different attachments are available in the Miyvac Kit.