The vacuum brake booster is located between the brake master cylinder and the firewall.
Older vehicles manufactured prior to the introduction of electronic control modules relied on mechanically engineered components to perform the functions now controlled by electronics and super computers.
The exhaust gas recirculation (EGR) system introduces exhaust gases to the engine combustion chamber to lower temperatures.
The cruise control vacuum reservoir is an air bladder that stores a supply of spare air that is vacuum pressured for when the primary vacuum runs low.
Many vehicles employ a vacuum brake booster in order to provide additional power to the braking system.