What will happen if the automatic slack adjuster fails?

If the automatic slack adjuster fails, the system will no longer be able to maintain the correct brake adjustment automatically. As a result, the driver will need to manually adjust the brakes more frequently to ensure they function properly. This is crucial for maintaining optimal braking performance and safety. Automatic slack adjusters are designed to reduce the need for manual adjustments by automatically compensating for brake wear, but if they malfunction, that responsibility shifts back to the driver, who must regularly check and adjust the brake system to prevent brake fade or failure.

The other options involve outcomes that do not directly relate to the function of the slack adjuster in the event of its failure. For example, the brakes will not inadvertently apply, nor will the air system overflow or the air compressor seize as a direct result of the slack adjuster's failure.