Technical characteristics of the brake system (Audi 100 C3)

The car has a dual-circuit brake system: one circuit brakes the left front and right rear wheels, and the other - the right front and left rear. The system drive is hydraulic. To facilitate the control of the drive, the car has a vacuum booster (models with 4-cylinder engines) or power steering (models with 5-cylinder engines). The front brakes are disc brakes. The rear brakes on models with 4-cylinder engines are drum brakes, on models with 5-cylinder engines they are disc brakes.

Warning: Since January 1988 the width of the brake drums has increased by 6 mm.

Rear wheel drum brakes
– brake shoe:
• friction lining thickness, mm	5,25
• minimum acceptable lining thickness (when worn out), mm	2,50
– brake drum:
• diameter, mm	230
• maximum permissible diameter, mm	231
• axial runout of the working surface, mm	no more than 0.20
• maximum permissible ovality, mm	no more than 0.10
– diameter of the wheel cylinder piston, mm	17,46

Disc brakes on front and rear wheels
Parameter	Brake shoe of the brake mechanism
	front wheel	rear wheel
Friction lining thickness, mm	14	12
Minimum permissible thickness of the friction lining (at wear), mm	2	2

Broadcast	Brake discs
	front		rear
Diameter, mm	256	276	245
Thickness, mm
- ventilated discs	22	25	–
- non-ventilated discs	13	–	10
Maximum allowable thickness (when worn out):
- ventilated discs	20	23	–
- non-ventilated discs	11	–	8
Non-flatness	0,02	0,01	0,02
End runout	0,06	0,03	0.06

(The original article is available on the website AudiManual)