What is the relationship between parking brake cable tension and rear brake shoe adjustment on a drum brake system?

Proper rear brake shoe adjustment is crucial for correct parking brake cable tension on a drum brake system. The parking brake cable applies force to a lever mechanism within the drum brake assembly, which in turn pushes the brake shoes outward against the inside of the brake drum. If the rear brake shoes are not properly adjusted to the correct clearance with the drum, the parking brake cable will either be too loose or too tight when the parking brake is engaged. If the brake shoes are adjusted too far away from the drum, the parking brake cable will have to travel a long distance to engage the brakes, resulting in a weak or ineffective parking brake. Conversely, if the brake shoes are adjusted too tightly against the drum, the parking brake cable will be under excessive tension, potentially leading to cable breakage or premature wear of the brake shoes and drums. Therefore, proper rear brake shoe adjustment is essential to ensure the correct parking brake cable tension and optimal parking brake performance. The brake shoes must be adjusted so that the cable applies the correct amount of force with a reasonable amount of travel.