TSB 82-21-5: Brakes - Rotor Service Update

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Article No. 85-9-8 Supercedes 85-4-12 BRAKE ROTOR SERVICE - UPDATED DIAGNOSIS AND SERVICE CHART FORD 1983-85 ALL LINCOLN-MERCURY 1983-85 ALL NOTE: Reprint of 85-4-12 to change title and correct copy. Technical Service Bulletin Number 82-21-5 refers to sanding the corrosion from the braking surface of the rotor for a brake roughness condition. Sanding is not effective for removing rust/corrosion or the black discoloration caused by semi-metallic brake linings on rotors. Rust/corrosion on the rotor surfaces does not affect performance unless it is thick enough to cause pulsation. The procedure in Condition 5, Step 1, should be revised to read as follows below. TSB 82-21-5 is being republished for your convenience. Continuing improvements by brake rotor suppliers in the overall quality level of manufacture and control of critical dimensions has made this change in procedure possible. Essentially, brake rotor service consists of sanding the braking surface or replacing the rotor when sanding is not effective. Following is an updated Brake Diagnostic and Service Chart. It lists most of the conditions a customer will mention when brake service is required, plus the probable causes and the recommended service. CONDITION POSSIBLE CAUSE SERVICE 1. Squeal - A loud, sharp, high- 1. Brake lining and/or rotor surface 1. Remove caliper assembly from pitched moderately prolonged contamination evidenced by glazed spindle and remove inner and outer sound that occurs while braking. surfaces. linings. Rotor removal from rear Occasional or intermittent brake drive vehicles is not necessary. squeal may result from Hand sand glaze from linings and environmental conditions such as both braking surfaces or rotor. Use cold, heat, wetness, snow, salt, Garnet Paper 100A (medium grit) or mud, etc. This condition is aluminum oxide 150J (medium). not a functional one and will not affect braking effectiveness. 2. Disc brakes - Missing or damaged 2. When the linings are not worn, brake pad insulators. replace the brake pad insulators. (See master parts catalog for insulator availability). 3. On drum brakes - Loose lining 3. Inspect, service or replace. rivets, weak, damaged or incorrect shoe retracting springs, loose or damaged shoe retainer pins, springs and clips, and grooved backing plate ledges. 2. Squeal or Squeak - Brakes not 1. Wheel cover attachment. 1. Seat covers with a rubber mallet. applied. Service flanges or replace cover. 2. Improper machining of drum, 2. Replace drum. causing interference with backing plate or shoe. 3. Bent or warped backing plate 3. Service or replace. or shoe. 4. Loose wheel attaching lug nuts. 4. Tighten to correct torque. Replace wheel if stud holes are damaged. 5. Other pans to check: 5. Inspect, service, replace as required. - Loose or extra pans in drum. - Drum brake adjustment too tight causing lining to glaze. - Drum brake shoe retracting springs weak, damaged or wrong parts. - Drum brakes - grooved backing plate ledges. - Improper positioning of shoe in caliper. - Outside diameter or rotor rubbing caliper housing. - Lack of correct lubricant on disc brake caliper slides (if applicable). - Improper installation of disc brake anti-rattle clip. - Worn, damaged, or insufficiently lubricated wheel bearings. 3. Rattle, Clunk, Knock, Click - 1. Caliper support pins. 1. Tighten or replace. Series of sharp, short sounds 2. Pin bushings. 2. Replace as necessary. in quick succession. 3. Pin teflon sleeve. 3. Replace as necessary. 4. Inner/outer shoe clips. 4. Service or replace as necessary. Ref. Technical Service Bulletin No. 80-11-2-S, dated 8/4/80. 5. Caliper hold-down spring (front 5. Service or replace as necessary wheel drive vehicles only). 6. Dust shield. 6. Service as necessary. 7. Grease shield (front wheel drive 7. Service as necessary. vehicles only). 8. Outer disc brake shoe locating 8. Check and reseat if necessary. buttons not seated in caliper holes. 9. Drum brakes - shoes binding at 9. Lubricate ledges. backing plate ledges. 10. Drum brakes - backing plate 10. Replace backing plate and lubricate. ledges worn. 11. Stones or foreign material trapped 11. Remove. inside wheel covers. 12. Loose grease cap. 12. Service or replace. 4. Grind - A loud, harsh rubbing 1. Bound caliper and/or brake shoes . 1a. For rear wheel drive vehicles, see noise. TSB 81-5, dated 3/16/81, Article 3727S. 1b. On front wheel drive vehicles, hand sand corrosion from knuckle surface where it touches brake shoe . 2. Contaminated linings. 2. Remove lining contamination as necessary. 3. Worn front or rear brake linings 3. Replace linings and refinish or or rear drum. replace drums. 4. Wheel bearings not lubricated 4. Lubricate and replace bearings and (verify noise is coming from seals as necessary. Hub nut must bearings). also be replaced and staked on front wheel vehicles. 5. Rear brake shoes - binding at 5. Lubricate or replace as necessary. backing plate ledges. 6. Caliper to wheel or rotor 6. Replace as required. interference. 7. Other pans to check: 7. Replace. -Warped or bent splash shield. -Warped or bent backing plate . -Cracked drum. -Cracked rotor. 8. Tires rubbing against chassis or 8. Inspect and service. body. 9. Rotor to spindle interference. 9. Replace as required. 5. Roughness - An unsmooth 1. Corrosion/rust build-up on rotor 1. Peform 5-10 moderate brake stops. feeling while braking in neutral surfaces. Do not sand rotors. If roughness evidenced by a pulsating brake persists, replace rotor(s). Black pedal. discoloration on rotors is caused by semi-metallic linings and should not be removed. Rust that does not cause pulsation should not be removed. 2. Rotor thickness variation. 2. Replace rotor. 3. Rear brake roughness. 3. Attempt stopping the vehicle using the parking brake. If roughness is present, check drums for excessive wear or runout. Refinish or replace as necessary. 4. Wheel bearings mis-adjusted. 4. Inspect and adjust bearing setting as necessary. 5. Wheel-tire imbalance. 5. Verify and service as necessary. Refer to TSB No.82-16. 6. Drivetrain imbalance. 6. Attempt stopping vehicle in neutral transmission position. If roughness is gone, drivetrain should be inspected. Refer to TSB No. 81-19A. OTHER APPLICABLE ARTICLES: 82-21-5 WARRANTY STATUS: "INFORMATION ONLY"