Test Values/Wear Limits - 911 C2/C4 And 911 C2S/C4S
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2019 Porsche 911, 2018 Porsche 911, 2017 Porsche 911, 2016 Porsche 911, and 2015 Porsche 911. However, it is still accessible from the selected car via links, so may be relevant.
Information
Depending on the wear of cast iron brake discs, two condition criteria can make replacement necessary:
- Cracking in the holed (perforated) brake disc friction plates is in an advanced state.
- Minimum brake disc thickness is not retained due to wear (material erosion due to friction).
| Location | Description | Type | Basic value | Tolerance 1 | Tolerance 2 |
|---|---|---|---|---|---|
| Pad thickness, front | All | Measured value | approx. 12.0 mm | ||
| Pad thickness, front (wear limit) | All | Measured value | 2 mm | ||
| Pad thickness, rear | All | Measured value | approx. 12.0 mm | ||
| Pad thickness, rear (wear limit) | All | Measured value | 2 mm | ||
| Brake disc thickness, new (front) | C2/C4 | Measured value | 28 mm | ||
| Brake disc thickness, new (front) | C2S/C4S | Measured value | 34 mm | ||
| Brake disc thickness, new (rear) | All | Measured value | 28 mm | ||
| Brake disc minimum thickness after machining, front C2/C4 | Brake disc can only be reworked symmetrically, i.e. equally from both sides! | Measured value | C2/C4 = 26.6 mm | ||
| Brake disc minimum thickness after machining, front C2S/C4S | Brake disc can only be reworked symmetrically, i.e. equally from both sides! | Measured value | C2S/C4S = 32.6 mm | ||
| Brake disc minimum thickness after machining, rear, all | Brake disc can only be reworked symmetrically, i.e. equally from both sides! | Measured value | All = 26.6 mm | ||
| Brake disc wear limit, front | C2/C4 | Measured value | 26.0 mm | ||
| Brake disc wear limit, front | C2S/C4S | Measured value | 32.0 mm | ||
| Brake disc wear limit, rear | All | Measured value | 26.0 mm | ||
| Peak-to-valley surface roughness of brake disc after machining (max.) | All | Measured value | 0.006 mm | ||
| Thickness tolerance of brake discs (max.) | All | Measured value | 0.02 mm | ||
| Lateral runout of brake disc (max.) | All | Measured value | 0.03 mm | ||
| Lateral runout of wheel hub (max.) | All | Measured value | 0.03 mm | ||
| Lateral runout of brake disc when installed (max.) | All | Measured value | 0.06 mm | ||
| Push-rod play | Measured at brake pedal plate | Measured value | approx. 1 mm | ||
| Diameter of parking-brake drum | Parking brake (electrically actuated, drum brake acting on the rear axle) | Diameter | 180 mm | ||
| Diameter of parking-brake drum, wear limit | All | Diameter | 181 mm | ||
| Width of parking-brake shoe | All | Measured value | 25 mm | ||
| Thickness of parking-brake pad | All | Measured value | 4.5 mm | ||
| Thickness of parking-brake pad, wear limit | All | Measured value | 2 mm |