Accord L4-2156cc 2.2L SOHC (1991)
Fig. 3 Exploded View Of Power Brake Booster. 1989-91 Prelude
The vacuum assist diaphragm assembly Figs. 1 through 3, multiplies the force exerted on the master cylinder piston in order to increase the hydraulic
pressure delivered to the wheel cylinders while decreasing the effort necessary to obtain acceptable stopping performance. Vacuum assist units get their
energy by opposing engine vacuum to atmospheric pressure. A piston, cylinder and flexible diaphragm utilize this energy to provide brake assistance.
The diaphragm is balanced with engine vacuum until the brake pedal is depressed, allowing atmospheric pressure to unbalanced the unit and apply force
to the brake system.
