2022-2024 Toyota Acid Rain Damage TSB T-SB-0035-24

Acid rain damage is a common issue affecting vehicle exteriors, particularly on horizontal surfaces like the hood, roof, and decklid. It occurs when acidic moisture in the air settles on the vehicle's paint, leading to visible stains that resemble hard water spots. Unlike regular water spots, these cannot be removed by simple washing and can etch or soften the paint, making traditional buffing or polishing ineffective and potentially harmful.

This Technical Service Bulletin, T-SB-0035-24, provides comprehensive guidelines for identifying, preventing, and repairing acid rain damage on various Toyota models from 2022 to 2024. It categorizes damage into minor, moderate, and severe, offering specific repair procedures for each.

Important Warnings for Repair

Toyota emphasizes several critical points for technicians and owners regarding the repair of Toyota acid rain damage:

• The repair process outlined in this bulletin should only be followed with matte paint finish safe products for vehicles with matte paint. Using materials listed in this document on matte paints can lead to damage.
• The procedures described are intended for use by qualified body/paint technicians and should not be attempted by inexperienced personnel.
• To minimize the possibility of burning through or hazing paint surfaces, buffing procedures must be performed only by personnel experienced in rotary power buffing.
• Regardless of the manufacturer, NEVER use different buffing/polishing compounds on the same pad.
• When buffing, use only LIGHT pressure on the buffer to prevent burn-through damage to the paint surface.
• While it is recommended to sand down into the primer coat for severe damage, the underlying electro deposition coat should NOT be exposed, as it provides essential corrosion protection.
• Lacquer-type paint is NOT recommended for repainting applications.
• Always check with State and Local ordinances regarding the use and disposal of all chemicals involved in the repair process.

Symptoms of Acid Rain Damage

Acid rain damage typically appears as stains on the paint surface, similar to hard water spots. However, these stains are more persistent and can lead to etching and visible depressions in the paint. The TSB categorizes the damage into three types:

• Minor Damage: This type of damage typically requires only buffing for repair.
• Moderate Damage: This level of damage usually necessitates neutralizing the affected area, color sanding, and then buffing.
• Severe Damage: When the damage extends beyond 1/2 mil of the clearcoat on pearl, metallic, or solid colors, it requires neutralization, sanding, and repainting.

Diagnosis and Assessment

For Toyota acid rain damage beyond minor cases, determining the actual depth of acid penetration is challenging. Technicians may need to color sand a representative affected area until no visible etching or depressions remain. This is followed by measuring the amount of paint removed using a magnetic or digital-type film thickness gauge. This precise measurement helps determine the appropriate repair strategy.

Repair Procedure Summary

The repair procedures for Toyota acid rain damage vary based on the severity. All procedures begin with ensuring the vehicle's paint surfaces are cool and out of direct sunlight.

Initial Steps (Common to all damage types)

1. Wash the vehicle surface thoroughly with automotive liquid soap and water.
2. Neutralize any remaining acid by applying a solution of one tablespoon of baking soda per quart of water using a commercial-grade plastic garden sprayer.
3. Rinse the vehicle thoroughly with fresh water.
4. For moderate and severe damage, measure the paint film thickness in several locations on the affected panel and record the measurements.

Minor Damage Repair

After the initial steps, buff the affected areas using the least aggressive pads and liquid compounds. Periodically measure the paint film thickness during buffing. The desired repair results should be achieved within approximately 30 minutes per vehicle. Very lightly affected areas can also be buffed using a 3M™ Perfect-It™ System or equivalent.

Moderate Damage Repair

Following the initial cleaning and neutralization, technicians will:

1. Mix liquid automotive washing soap in a pail of clean water and immerse #1500 or #2000 grit wet-dry sandpaper for several minutes.
2. Carefully color sand affected paint areas using the wet-dry sandpaper with a soft foam rubber sanding pad. Clean water should be frequently applied to maintain a clean working surface and prevent clogging.
3. Continuously measure paint film thickness before, during, and after sanding to prevent excessive paint removal. No more than a total of 1/2 mil of clearcoat should be removed on pearl, metallic, and solid colors. Always sand in one direction, never in a circular pattern.
4. Install a recommended buffing pad on a variable speed rotary buffer (1200–1800 rpm depending on pad type).
5. Apply buffing/polishing material sparingly to a small section and buff until the haze is almost gone, using light pressure.
6. Inspect the buffed area for remaining acid spots. If any are found, further sanding and polishing may be necessary.
7. Continue buffing and re-sanding as needed, ensuring paint film thickness is continuously monitored.
8. Complete with a final buffing/polishing to achieve a high-gloss finish.

Severe Damage Repair

If acid damage has penetrated more than 1/2 mil after color sanding, the following steps for sanding and repainting are required:

1. Wash the vehicle surface with mild automotive soap and water, then rinse with deionized water. Clean affected areas with an appropriate silicone/wax remover.
2. Completely sand the affected areas using a dual-action sander to eliminate any depressions. While sanding into the primer coat is recommended, avoid exposing the underlying electro deposition coat.
3. Finish sanding the surface with wet-dry sandpaper using the grit recommended by the paint manufacturer.
4. Wash and rinse the vehicle surface again with deionized water.
5. Clean sanded areas with an appropriate silicone/wax remover.
6. Apply a quality urethane enamel color coat or base coat/clear coat for maximum repair durability, following paint manufacturer recommendations.

Required Tools and Materials

To perform these repairs, the following tools and materials are recommended:

• Liquid Automotive Washing Soap
• Baking Soda
• Water Pail
• 3M™ Finesse-It™ II Machine Polish (or Equivalent)
• 3M™ Perfect-It™ System (or Equivalent)
• 3M™ Finesse-It™ II Wool Pad (or Equivalent)
• 3M™ Perfect-It™ Foam Pad (or Equivalent)
• #1500 or #2000 Grit Wet-Dry Sandpaper
• Variable Speed Rotary Buffer (1200 - 1800 rpm)
• Elcometer® 211 Mechanical Coating Thickness Gauge, Magnetic (or Equivalent)
• Fischer® Deltascope DMP30, Digital (or Equivalent)

Owner Action

To minimize the potential for Toyota acid rain damage, perform frequent vehicle washing, especially during high heat and humidity periods or in geographical areas known for high frequency of acid rain and industrial fallout. If you notice any signs of acid rain damage, particularly etching or visible depressions, it is recommended to visit a qualified Toyota dealership or body shop. The procedures in this TSB are complex and require specialized tools and expertise.

Supersession Notice

This bulletin, T-SB-0035-24, supersedes Service Bulletin No. B091-020. The information in the previous bulletin is now obsolete, and any printed versions should be discarded.

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Source: NHTSA ID: 11003644