Test Values/Wear Limits - 911 C2/C4 And 911 C2S/C4S
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 |