Machining Brake Drums & Rotors

Brake drums use ________ for the friction surface area.

• cast iron    

• aluminum

• steel

• carbon

Technician A says that hard spots in a brake drum should be removed using a carbide-tip machining tool. Technician B says that the drum should be replaced if hard spots are discovered. Which technician is correct?

• Tech A

• Tech B

• Both Tech A and Tech B

• Neither Tech A nor Tech B

The major reason for brake pedal pulsation during braking is due to___________.

• grooved rotors

• excessive rotor thickness variation    

• thin rotors

• poor surface finish on the rotors

After machining a rotor, what should be done?

• Installed on the vehicle

• Clean the rotor with soap and water    

• Rub the machined surface with a brake pad to burnish the surface

• Use new lug nuts when installing on the vehicle

The brake lathe arbor should be checked using a ________.

• feeler gauge

• vacuum gauge

• thread pitch gauge

• dial indicator    

Two technicians are discussing hard spots in brake drums. Technician A says the drum should be replaced. Technician B says the hard spots are caused by using riveted rather than bonded brake shoes. Which technician is correct?

• Tech A

• Tech B

• Both Tech A and Tech B

• Neither Tech A nor Tech B

Hard spots in a brake drum are caused by ________.

• improper mounting of the drum on the lathe

• machining a drum at too high a speed

• excessive heat and pressure

• machining a drum without using a rubber belt to damper out the vibrations

Which is NOT a type of brake drum construction?

• Composite

• Bimetallic

• Centrifugally cast

• Solid composite

Which one is not a form of drum distortion?

• Eccentric

• Lack of parallelism

• Out-of-round

• Bellmouth

The chamfer on the inside edge of a brake drum usually indicates ________.

• machine to diameter

• maximum allowable inside diameter

• aluminum drum with cast iron inset

• bimetallic drums (1/2 cast iron and 1/2 steel)