How can you check the automatic slack adjuster cam splines?

Measuring the free movement of the automatic slack adjuster cam splines is a crucial step in ensuring proper function. The slack adjuster's role is to maintain optimal brake adjustment automatically, compensating for wear in the brake linings. By measuring the free movement, you can determine whether the slack adjuster is functioning correctly and can effectively adjust the brake shoe position as needed. If there is excessive play or minimal movement, it indicates potential wear or malfunction, which could lead to improper brake adjustment and performance issues.

While other factors like visible wear marks, lubrication levels, and the presence of rust and corrosion can provide useful insights into overall condition, they do not specifically measure the functional capability of the slack adjuster in terms of necessary movement. Therefore, measuring the free movement directly assesses the operational integrity of the slack adjuster cam splines, making it the most relevant method for evaluation.