Checking Grey Cast-Iron Brake Discs - Minimum Thickness
Information
- Replace brake discs once the maximum wear dimension has been reached.
- Re-machining of brake discs is not permitted!
Information
Irrespective of the crack length, the brake disc must be replaced if the crack has extended as far as the outer and/or inner edge of the disc.
As the pressure force of a brake piston on the brake pad varies in magnitude, different areas of wear arise on the friction surface. The brake disc can basically be divided into two areas of wear:
Outer and centre wear areas.
The natural balance between stronger and weaker braking ensures that in almost all cases the typical wear profile of a perforated (cross-drilled) brake disc (friction plate) arises.
This means: the inner and outer smooth friction edge zone is most worn.
Outer wear areas
Centre wear areas
Information
Unlike smooth brake discs, on which the minimum thickness is measured in the middle of the disc, the minimum thickness of perforated (cross-drilled) brake discs must always be measured on the inner and outer friction surface track that is most worn -arrows- .
Wear areas A and B
| A | Central wear area |
| B | Outer and inner wear area |
Information
The brake disc thickness tolerance can be found under Technical data/brake wear limits.
4600TW GREY CAST-IRON BRAKES - TECHNICAL VALUES AND WEAR LIMITS
- Measure brake disc thickness.
Measure the brake disc thickness -X- in the area of the outer or inner friction surface toe -Arrows- on at least three different points (-A, B, C- ) offset by 120°.
To do this, use a suitable micrometer screw or a brake disc gauge.
Measurement points for brake disc thickness