The hydraulic brake system employed by Subaru has gone through several changes since 1970.
In 1970 through 1972, the front brakes on the ff-1 and 1300G models were a duo servo, single anchor type drum brake. This system employs brake shoes as do the rear brakes, but the duo servo action provides better braking effect. Also, the front brakes were mounted inboard (on either side of the differential housing) to improve handling.
Since the front suspension system on the GL and DL models was changed in 1972 to a MacPherson strut type, inboard front brakes were no longer necessary as a suspension improvement. Thus, the front brakes were mounted at the ends of the axle shafts (outboard) for easier serviceability. The duo servo type brake was continued for all sedans and wagons through 1975, although GL and G models were equipped with front disc brakes.
Since 1976, all models were equipped with front disc brakes. This system employs piston pressure to force two pads against both surfaces of a disc, or rotor. The advantages of disc brakes are in over all braking effect, road stability during braking and service life of the brakes.
The master cylinder used on ff-1 and 1300G models is a conventional, single chamber master cylinder which supplies hydraulic pressure to all four wheel cylinders. All other models are equipped with a tandem master cylinder, which employs a dual hydraulic circuit with each circuit supplying pressure to diagonally opposed wheels. This is a safety feature which allows for at least 50% braking action in case of fluid leak at any one wheel.
The final improvement of the hydraulic brake system was the incorporation of a vacuum, suspended type power brake unit, which provides better response than manual brakes. Since the power unit uses engine vacuum for its operation, it cannot function when the engine stalls out. This does not mean, however, that all braking power is lost, rather, the brake pedal will simply require greater foot pressure to stop the vehicle. Power brakes are standard from 1975 except on the 1975 2-door sedan.
On all models the handbrake is mechanically operated and attached to the front wheels by means of a cable.