Technical Data

The technical data are valid for the 911 Carrera 4 and 911 Carrera 4 Turbo Look. C4 TL = 911 Carrera 4 Turbo Look.


Remarks, dimensions

Wear Limit

Service brake (foot-operated)

Hydraulic dual circuit brake system with front/rear axle brake circuit division.

Hydraulic brake booster, inboard vented brake discs with four-piston fixed calipers front and rear. The pushrod circuit is applied to the front axle. ABS standard.

Brake booster Boosting factor

hydraulic 4.8

Brake master cylinder 0 front 0 rear Stroke

23.81 mm 23,81 mm 20/12 mm

Brake force regulator Switchover pressure reducing factor C4


55 bar - 0,46 33 bar - 0,46

299 mm

Effective brake disc 0 front rear C4 rear C4 TL

248 mm 246 mm

249 mm

Piston 0 in brake caliper front rear C4 rear C4 TL

2 x 40 + 2 X 36 mm 2 X 30 + 2 X 28 mm 2 x 34 + 2 x 30 mm

Brake pad area front rear

172 cm2 172 cm2

Total brake pad area

344 cm2

Pad thickness front rear

approx. 12 mm approx. 12 mm

2 mm 2 mm

Technical Data

Printed in Germany - XVIII, 1992

Technical Data

Printed in Germany - XVIII, 1992


Remarks, Specification

Wear Limits

Brake disc thickness (new), front

28 mm

rear C4

24 mm

rear C4 TL

28 mm

Brake discs

Minimum thickness* after machining


26.6 mm

26.0 mm

rear C4

22.6 mm

22.0 mm

rear C4 TL

26.6 mm

26,0 mm

Max. brake disc thickness tolerance

0.02 mm

Max. brake disc lateral runout

0.05 mm

Lateral runout of wheel hub, max.

0.05 mm

Max. lateral runout of brake disc

in installed state

0.1 mm

Max. peak-to-valley surface finish

after machining

0.006 mm

Push rod play

(measured on brake pedal plate)

approx. 8 mm

Parking brake

mechanical via brake drur

ns on both rear wheels

Brake drum 0

180 mm

181 mm

Brake shoe width

25 mm

Brake liner thicknesss

4.5 mm

2 mm

4 Brake discs may only be machined symmetrically, i. e. uniformly on both sides.

Technical Data

Printed in Germany - XVIII, 1992

Checking Thickness of Brake Pads


All brake pads on one axle must be replaced when the brake pad wear warning lamp lights up or at the latest, however, with a residual pad thickness of 2 mm.

If the warning lamp reports brake pad wear, the warning contact (sender incl. electric lead and plug) must also be replaced. Replacement of the warning contact can be prevented by replacing the brake pads at the latest when worn to a thickness of 2.5 mm. Warning contacts with a ground electric lead core must be replaced. Replacement is not necessary, however, if only the plastic part of the warning contact is ground.

1. Remove wheels to check the brake pads.

2. Check brake pads visually for wear.

Wear limit has been reached when a pad is worn to a residual thickness of 2 mm.

Checking Thickness of Brake Pads

Printed in Germany - III, 1989

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