RP 627C - Brake Lining Structural Defects: Introduction

For purposes of this RP, TMC classifies brake deficiencies as being either "in-service" or "out-of-service." In-service refers to conditions which need repair but which do not preclude safe operation of the vehicle. Out-of-service deficiencies pose an imminent danger for operation of the vehicle and are consistent with CVSA's Out-of-Service Criteria  .

Certain brake lining defects are not hazardous nor will they adversely affect the brake performance. Lining defects can be caused by poor quality, incorrect processing, material delamination, improper brake geometry, defective shoes, improper fastening techniques, or the operational and environmental conditions in which the brakes are used. Defects can also be caused by operational and environmental conditions in which the brakes are used. Identifying the defect and its cause can help determine if the vehicle demands immediate repair, or can continue in service with no loss of brake performance.

The initial intent when developing this RP was to have one document for both CVSA and TMC. After submitting this RP to CVSA; however, it became apparent that a single document representing the policy of both organizations would not be sufficient because the CVSA inspection only addresses wheel-on conditions, thereby precluding a check with the wheel and drum off and the lining face exposed. Therefore, this RP is intended to augment, not substitute, the CVSA standard.