Final answer:
When checking slack adjuster travel during a brake application, the travel should not exceed a certain limit set by the manufacturer.
Step-by-step explanation:
When checking the slack adjuster travel while someone makes a brake application, the travel should not exceed a certain limit. The limit depends on the specific vehicle and brake system being used. However, in general, the maximum allowable travel for a slack adjuster is typically specified by the manufacturer and is often around 1 inch.
Exceeding this limit can indicate excessive wear or improper adjustment in the brake system, which can compromise braking performance and safety. It is important to regularly check and adjust the slack adjuster to ensure proper brake function.