TROUBLESHOOTING BRAKE DRUMS
Replacement of the brake drum is required if any of the following conditions exist:
Brake drum is cracked.
The brake surface is heat checked, grooved, or worn beyond the re-bore limit of 0.080, or
The back plate is cracked.
The boltholes are elongated.
Brake drum is known to have been severely overheated.
Brake drum is out -of-round enough that truing would exceed re-bore limit.