Test Values And Wear Limits For Brake System (R4)
WARNING: This page is about a different variant/trim than selected.
Information
Depending on the wear of grey cast-iron brake discs, two condition criteria can make replacement necessary:
- Advanced stages of cracking on the brake disc friction surfaces.
- Minimum brake disc thickness is not retained due to wear (material erosion due to friction).
> 465002 - CHECKING FRONT BRAKE DISCS (GREY CAST IRON)
| Location | Description | Type | Basic value | Tolerance |
|---|---|---|---|---|
| Pad thickness, front | Pad quality ECE/wear limit 2 mm | Dimension | 10.58 mm | |
| Pad thickness, front | Pad quality NAR/wear limit 2 mm | Dimension | 10.58 mm | |
| Pad thickness, rear | Wear limit 2 mm | Dimension | 11.6 mm | |
| Brake disc wear dimension, front | Minimum thickness | 28 mm | ||
| Brake disc wear dimension, rear | Minimum thickness | 20 mm | ||
| Lateral runout of brake disc, maximum | Control value | 0.03 mm | ||
| Lateral runout of wheel hub, maximum | Control value | 0.03 mm | ||
| Lateral runout of brake disc when installed, maximum | Control value | 0.06 mm |
- Damage due to lack of use (rusting): this causes vibrations in the steering wheel, noises and brake pedal pulsation
- Brake disc becomes distorted as a result of serious driving
- Too much lateral runout when new brake discs are fitted on dirty or distorted wheel hubs
Procedure
- Check brake disc for cracks, minimum thickness, lateral runout, thickness tolerance, flatness and surface roughness
- Replacing brake discs
- Machining of brake discs is not permitted!