Over recent years, long stroke brake chambers have become standard on a range of models. These are not easily identifiable and a mismatch will also lead to an imbalance issue. Suppliers always recommend fitting matching chambers and other componentry.
Incident cause:
Brake imbalance can create vehicle stability issues. The fewer the axles in a group, the more important brake balance becomes, with a short wheel base 4×2 prime mover being the most susceptible to poor balance induced stability issues. Operators frequently receive defects for brake imbalance, as confirmed by an ATA survey of trucking operators.
Solution:
Ensure components are identical across an axle and, optimally, within an axle group.
Identify long stroke brake chambers by two of the following methods:
- Trapezoidal shaped tag with the stroke information detailed
- Square boss around the chamber’s air supply port or ports
- Embossed or cast-in service instruction advising chamber details
Follow-up actions:
Follow up with:
- Safety related replacement parts should be either original or certified as being equivalent to original parts
- Identical parts must be used across an axle and, optimally, within an axle group
- Ensure parts and workshop staff can identify long stroke brake chambers.