Dealer Service Information Bulletin 68-I-Special – Warranty Policy Clarification for Brake Drum Turning

This bulletin establishes a uniform policy to be adhered to when making adjustments under warranty for brake drum turning. Measuring the brake drum — both for total diameter and eccentricity — is essential before any turning. Reference is made to previous bulletin 67-T-22, covering the procedure to correct brake shudder. Many drums have been cut beyond specifications because they had been previously cut and no measurement was made.

The following policies will apply when turning brake drums:

1. Scored Drums — Grooves less than .020″ deep will not affect brake operation, and drums should not be turned for this condition.
2. Out-of-Round Drums — Determine if shudder is caused by front or rear drums (use parking brake to make determination). Turn both front (or rear) drums the same amount, but in no case take more than a .010″ cut (.020″ diameter). If the problem is not corrected after taking a .010″ cut, replace the drum.
3. Drums with Hard Spots — Drums containing hard (dark) spots indicate overheating. These spots, unless raised, do not affect brake operation and need not be removed. When turning drums with hard spots for a brake shudder complaint, use a cutting tool specifically manufactured to remove hard spots.

This is a transcription of the original dealer bulletin for easier reading and search. The complete original scan is shown below.