In the adjustment of cam brakes, what is measured after applying the air brakes fully?

When cam brakes are adjusted, one of the key measurements taken after fully applying the air brakes is the distance traveled by the push rod from the face of the brake chamber. This distance is crucial because it directly relates to the proper functioning of the brake system. The push rod's travel indicates how effectively the brake is being applied and ensures that there is adequate clearance for the drums or discs, maintaining efficient braking performance.

Essentially, measuring the push rod travel after full application helps inspectors determine if the brakes are adjusted correctly. If the travel is too great or too little, it may indicate a need for adjustment, signaling that the brake components may not be engaging or releasing as designed. Proper push rod measurements ensure safety and performance in braking systems, which is fundamental for vehicle operation.

Other options, such as measuring the time taken for pressure to build or the drop in pressure per minute, are more associated with the overall inspection of the air system rather than the specific adjustment oversight of cam brakes. The temperature of the brake system can be relevant to evaluating brake performance but does not pertain directly to the adjustment process for cam brakes.