Single vs Dual Diaphragm Brake Booster

SINGLE DIAPHRAGM BOOSTERS work well with four wheel drum systems or front disc brakes and rear drum applications. These braking systems are lighter than the four wheel disc systems and work well on older cars because drum brakes were a common feature, at least on the rear axle.

DUAL DIAPHRAGM BOOSTERS are needed for four wheel disc systems because they can produce a higher level of brake assist even if their physical size is smaller. Dual diaphragm brake boosters tend to give extra braking even when the vacuum from the intake manifold is low.

BOOSTER SIZE is an important consideration. Power brake boosters require 17" of vacuum or more to function properly. Smaller brake boosters are great for tight spaces, but may require up to 22" of vacuum in order to function properly.