Brakes
Brake Disc
The brake disc (rotor) is squeezed by the pads to slow the wheel.
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Brake system flow
Interactive — tap a partTap a part to see how it fits in the system.
What it does
- Provides a friction surface for the pads
- Dissipates heat generated by braking
- Vented discs cool faster on heavy cars
When it fails
- Pulsing through the brake pedal
- Grinding or scraping noise
- Vibration in the steering wheel under braking
- Deep grooves or bluing on the surface
How to diagnose
- Measure thickness with a micrometer against the minimum
- Check for run-out with a dial gauge
- Look for cracks, bluing or uneven wear
Maintenance
- Replace discs in axle pairs
- Always fit new pads with new or re-faced discs
- Bed in new discs gently
Use the diagnosis order. When a part fails, confirm each hypothesis with measurements before replacing anything — codes and symptoms overlap.
Related part
Brake Pads
Brake pads press against the disc to convert motion into heat and slow the car.