Brake system characteristics (Audi 80 B3)

System type - With front disc and rear drum or disc brakes, dual diagonally split hydraulic circuit and vacuum and hydraulic servo booster. Rear brake pressure regulator and cable-actuated handbrake acting on the rear wheels. Some models have anti-lock braking system (ABS system).

Rear disc brakes

• Diameter - 245 mm
• Thickness (new disks) — 10.0 mm
• Thickness (minimal) — 8.0 mm

Rear disc brake pads

• Thickness of pads (new) - 12.0 mm
• Thickness of the pads (minimal) — 2.0 mm
• Minimum thickness of the pad (together with the rear shield) — 7.0 mm

Rear drum brakes

Inner diameter of drum:

• New drum - 200.0 mm
• Maximum diameter - 201.0 mm

Drum radial runout - 0.05 mm

Lateral drum runout (maximum) on the mounting surface of the wheel - 0.20 mm

Rear brake shoes for drum brakes

• Thickness of pads (new) - 5.25 mm
• Thickness of the pads (minimal) — 2.5 mm

Brake fluid

Type/Specification - Hydraulic fluid according to FMVSS 116 DOT 4 specification (Duckhams Universal Brake and Clutch Fluid)

Vacuum servo amplifier

Amplifier size - 9 inches

Hydraulic servo gain ratio is 4.7:1

Gas pressure in the pneumatic accumulator of the hydraulic servo booster (at 20°C):

• New pneumatic accumulator - 88-92 bar
• Minimum pressure - 30 bar