What must be ensured when replacing S-cams on an air brake equipped vehicle?

When replacing S-cams on an air brake equipped vehicle, it is essential to ensure that the S-cams have the correct rotation designation. S-cams are a critical component of air brake systems in heavy vehicles; their design and orientation dictate how the brake shoes engage with the brake drum. If the S-cams are installed with the incorrect rotation designation, it can lead to uneven braking, reduced braking efficiency, and potential safety hazards.

Correctly identifying the direction in which the S-cams are supposed to rotate is crucial for the proper function of the brake system. Proper orientation helps ensure that the brake shoes apply pressure evenly, providing effective braking performance and maintaining the integrity of the braking system. Therefore, ensuring the correct rotation designation is fundamental to the safe operation of the vehicle after the S-cams have been replaced.