What indicates that brakes require adjustment?

Excess play in the slack adjuster is a clear indication that the brakes require adjustment. The slack adjuster is a critical component in the brake system that helps to maintain the proper distance between the brake shoes and the drum. If there is too much play, it suggests that the brakes may not be engaging effectively, leading to reduced braking performance or increased stopping distances. Regular checks of the slack adjuster are essential to ensure safety and reliability in brake function.

In contrast, high usage of brake fluid may refer to leaks or wear that could necessitate attention, but it does not directly indicate a need for brake adjustment. The absence of warning lights could suggest that the system is functioning normally, but it does not provide information on brake adjustment needs. Lastly, while a driver's experience or perception can provide valuable insights, it is subjective and may not accurately reflect the mechanical state of the brakes, making it less reliable as an indicator for adjustments.