Document R5qVzOo5z5JR94kY6RVQv1nV

LESSON ONE-MODULE 2 BRAKE DRUM INSPECTION BRAKE SYSTEM SERVICE Scored Drum and Hard Spots on Drum Surface Item Description 1 Scored Surface 2 Drum 3 Shoe Item 4 lining 5 Hard Spots Description Brake drums must be inspected for excessive wear and damage. As with disc brake rotors, brake drums have certain specifications that must be met or the drum must be machined or replaced. There are many conditions that affect the operating performance of brake drums. The first check is a visual inspection. Visual Inspection Visually check the brake drum for cracks and scoring. Excessive scoring will require drum machining or replacement. Inspect the drum for hard spots. Hard spots are caused by extreme heat and pressure. Often these spots are not readily visible until after the drum has been machined, and they appear as small bumps on the friction surface. These hard spots, as well as any excessive scoring must be removed, or drum replacement is required. Any cracks in a brake drum can lead to a drum failure. Cracked drums must be replaced. 42 September, 2005 Brake System Diagnosis and Repair