T-SB-0035-24

Rev1

April 19, 2024

Prevention and Repair of Acid Rain Damage
Service
Category

Vehicle Exterior
Market USA and

Section

Mexico

Exterior Panels/Trim

Applicability
YEAR(S)

MODEL(S)

2025

4Runner HV, Crown Signia

1992 - 2025

4Runner, 86, Avalon, Avalon
HV, Avanza, bZ4X, C-HR,
Camry, Camry HV, Celica,
Corolla, Corolla BR-Prod,
Corolla Cross, Corolla Cross
HV, Corolla Hatchback,
Corolla HV, Cressida,
Crown, Echo, FJ Cruiser,
GR Corolla, Grand
Highlander, Grand
Highlander HV, Hiace,
Highlander, Highlander HV,
Hilux, iA, iM, Land Cruiser,
Matrix, Mirai, MR2, Prius,
Prius C, Prius PHV, Prius
Prime, Prius V, Raize,
RAV4, RAV4 EV, RAV4 HV,
RAV4 Prime, Sequoia,
Sequoia HV, Sienna, Sienna
HV, Solara, Supra, Tacoma,
Tacoma HV, Tundra, Tundra
HV, Venza, Venza HV,
Yaris, Yaris R, Yaris SD
MEX-Prod, Yaris SD THAIProd, Yaris THAI-Prod

ADDITIONAL INFORMATION

© 2024 Toyota Motor Sales, USA

Page 1 of 8

T-SB-0035-24

Rev1

April 19, 2024

Page 2 of 8

Prevention and Repair of Acid Rain Damage

REVISION NOTICE
July 12, 2024 Rev1:
 Applicability has been updated to include 2025 model year 4Runner Hybrid and
Crown Signia vehicles.
Any previous printed versions of this bulletin should be discarded.

SUPERSESSION NOTICE
The information contained in this bulletin supersedes Service Bulletin No. B091-020.
 The entire bulletin has been updated.
Service Bulletin No. B091-020 is obsolete and any printed versions should be discarded.

Introduction

Acid rain results from rainwater or other airborne moisture that become acidic due to industrial
chemical impurities in the atmosphere. If these acidic compounds settle on an exposed vehicle,
especially the horizontal areas such as the hood, roof, and decklid, significant damage to the
painted surfaces can occur. Acid rain damage can typically be identified on vehicles by the
presence of stains on the paint surface that resemble hard water spots. Unlike water spots
however, acid rain damage cannot be removed by regular washing procedures. Also, because acid
rain can etch and soften the paint, normal buffing or polishing repair procedures should not be
attempted. This can cause further damage and result in visible depressions in the paint surface.
The following are the three major categories of acid rain damage:


Minor damage: requires only buffing to repair.



Moderate damage: usually requires neutralizing, color sanding, and buffing.



Severe damage: extending beyond 1/2 mil of clearcoat on a pearl, metallic, or solid color,
requires neutralization, sanding, and repainting.
NOTICE
The following process can be followed but with matte paint finish safe products ONLY.
Using materials listed in this document can lead to paint damage to matte paints.

In cases where acid rain damage is minor, neutralization and buffing with a liquid-type paint
finessing product may provide an adequate repair. Only specially formulated products outlined in
this bulletin should be used for that purpose.

© 2024 Toyota Motor Sales, USA

T-SB-0035-24

Rev1

April 19, 2024

Page 3 of 8

Prevention and Repair of Acid Rain Damage
Introduction (continued)

Unfortunately, other than minor damage, there is no simple method of determining the actual
extent (depth) of acid penetration other than color sanding a representative affected area until
there is no visible etching or depressions, followed by measuring the amount of paint removed with
either a magnetic or digital-type film thickness gauge. The procedures in this bulletin are intended
for use by qualified body/paint technicians and should not be attempted by
inexperienced personnel.
It is the dealer’s responsibility to protect and maintain the quality of the vehicle’s paint finish after
receipt at the dealership prior to the first sale. Perform frequent vehicle washing, as often as daily,
during high heat and humidity periods to minimize the potential for paint damage due to acid rain
exposure. This is especially important in geographical areas known for high frequency and
concentration of acid rain and industrial fallout. Follow the Repair Procedure in this bulletin to
address minor, moderate, and severe acid rain damage.

Warranty Information
OP CODE

DESCRIPTION

TIME

OFP

T1

T2

N/A

Not Applicable to Warranty

–

–

–

–

Required Tools & Equipment
REQUIRED TOOLS & MATERIAL

QUANTITY

Liquid Automotive Washing Soap, Baking Soda, Water Pail

As Needed

3MTM Finesse-ItTM II Machine Polish (or Equivalent)

1

3MTM Perfect-ItTM System (or Equivalent)

1

3MTM Finesse-ItTM II Wool Pad (or Equivalent)

1

3MTM Perfect-ItTM Foam Pad (or Equivalent)

1

#1500 or #2000 Grit Wet-Dry Sandpaper Pre-Soaked in Clean Water

As Needed

Variable Speed Rotary Buffer, Speed Range 1200 – 1800 rpm

As Needed

Elcometer® 211 Mechanical Coating Thickness Gauge, Magnetic (or Equivalent)

1

Fischer®

Deltascope DMP30, Digital (or Equivalent)

© 2024 Toyota Motor Sales, USA

1

T-SB-0035-24

Rev1

April 19, 2024

Page 4 of 8

Prevention and Repair of Acid Rain Damage
Repair Procedures



Repair Procedure for Minor Damage ....................................................................................... 5



Repair Procedure for Moderate Damage ................................................................................. 6



Repair Procedure for Severe Damage ..................................................................................... 8

© 2024 Toyota Motor Sales, USA

T-SB-0035-24

Rev1

April 19, 2024

Page 5 of 8

Prevention and Repair of Acid Rain Damage
Repair Procedure
Repair Procedure for Minor Damage

1. Move the vehicle out of direct sunlight to allow paint surfaces to cool.
NOTE
Dark painted colors become warmer in direct sunlight and require a longer period to cool.

2. When the vehicle temperature surfaces are cool, wash the vehicle surface with automotive
liquid soap and water.
3. Neutralize any remaining acid with a solution containing one tablespoon of baking soda per
quart of water, applying the solution with a commercial grade plastic garden sprayer.
4. Rinse the vehicle thoroughly with fresh water.
5. Take accurate measurements of paint film thickness in several locations on an affected
body panel.
6. Record the measurements on a short piece of masking tape and attach it to the panel area
adjacent to the measurement area.
NOTICE
To minimize the possibility of burning through or hazing paint surfaces, the following buffing
procedures should be performed only by personnel experienced in rotary power buffing.

7. Buff the affected areas, using the least aggressive pads and liquid compounds.
A. Periodically measure the paint film thickness during the buffing process.
B. Buffing should provide the desired repair results within a short period of time
(approximately 30 minutes per vehicle)

8. Very lightly affected areas may alternatively be buffed using 3MTM Perfect-ItTM System
(or equivalent).

© 2024 Toyota Motor Sales, USA

T-SB-0035-24

Rev1

April 19, 2024

Page 6 of 8

Prevention and Repair of Acid Rain Damage
Repair Procedure (continued)
Repair Procedure for Moderate Damage

1. Move vehicle out of direct sunlight and allow paint surfaces to cool if necessary.
NOTE
Dark painted colors become warmer in direct sunlight and require a longer period to cool.

2. When the vehicle temperature surfaces are cool, wash the vehicle surface with automotive
liquid soap and water.
3. Neutralize any remaining acid with a solution containing one tablespoon of baking soda per
quart of water, applying the solution with a commercial grade plastic garden sprayer.
4. Rinse the vehicle thoroughly with fresh water.
5. Mix liquid automotive washing soap in a pail of clean water (follow manufacturers mixing
instructions) and immerse recommended wet-dry sandpaper.
NOTE
Allow the sandpaper to soak for several minutes.

6. Using a #1500 or #2000 grit wet-dry sandpaper with a soft foam rubber sanding pad, carefully
color sand affected paint areas.
A. To maintain the cleanest possible working surface and prevent clogging of paper,
frequently apply clean water from a hand-held spray pump bottle.
B. During this process, wipe down sanded areas often to determine if spots have
been removed.
NOTE
 When performing this procedure, be sure to measure paint film thickness before, during
(continuously), and AFTER sanding with a film thickness gauge to prevent excess paint removal.
 The ideal instruments to monitor paint film thickness during the color sanding operation are
magnetic or digital thickness gauges.
 Consult your local paint or tool jobber for pricing and availability. In all color sanding situations
remove no more than a total of 1/2 mil of the clearcoat on pearl, metallic, and solid colors.
 ALWAYS sand in one direction and never in a circular pattern.

© 2024 Toyota Motor Sales, USA

T-SB-0035-24

Rev1

April 19, 2024

Page 7 of 8

Prevention and Repair of Acid Rain Damage
Repair Procedure (continued)
Repair Procedure for Moderate Damage (continued)

7. Install one of the recommended buffing pads, setting the buffer speed to 1200 – 1800 rpm for
Meguiar's foam pads (or equivalent) or 1500 –1800 rpm for 3MTM wool pads (or equivalent).
NOTE
Regardless of manufacturer, NEVER use different buffing/polishing compounds on the same pad.

8. Based on manufacturer guidelines, apply recommended buffing/polishing material sparingly to
about a 2 sq. ft. (0.186 sq. meter) section of the affected panel and wipe buffer pad once
across the area.
Begin and continue buffing area until haze of material is almost gone.
NOTICE
Use only LIGHT pressure on the buffer to prevent burn-through damage to the paint surface.

9. Carefully inspect the buffed paint area for remaining acid spots. If any are found, further
sanding and polishing is necessary.
10. Continue to buff surface and if necessary, re-sand the remaining affected areas. Be sure to
continuously measure the paint film thickness during sanding to prevent excess film removal.
As stated previously, remove no more than 1/2 mil on clear coats and 1 mil on solid colors.
11. Following completion of color sanding procedure, carry out final buffing/polishing procedure to
achieve a hi-gloss finish.

© 2024 Toyota Motor Sales, USA

T-SB-0035-24

Rev1

April 19, 2024

Page 8 of 8

Prevention and Repair of Acid Rain Damage
Repair Procedure (continued)
Repair Procedure for Severe Damage

If it has been determined that the acid damage has penetrated more than 1/2 mil on a metallic,
pearl color or solid color after color sanding, the following guidelines for sanding and repainting
should be followed.
1. Wash vehicle surface using mild automotive soap and water, and rinse with deionized water
until ALL residue is removed. Clean the affected areas with an appropriate silicone/wax
remover (DuPont 3939, PPG DX330/DX380, or equivalent).
2. Using a dual action sander, completely sand the affected areas to eliminate any depressions
in the paint surface.
NOTE
While it is recommended to sand down into the primer coat, the underlying electro deposition coat
should NOT be exposed, since it provides essential corrosion protection.

3. Finish sanding the surface with wet-dry sandpaper using the grit number as recommended by
paint manufacturers.
4. Wash vehicle surface using mild automotive soap and water.
5. Rinse with deionized water until ALL residue is removed from the surface.
6. Clean sanded areas with an appropriate silicone/wax remover (DuPont 3939,
PPG DX330/DX380, or equivalent).
NOTE
While it is recommended to sand down into the primer coat, the underlying electro deposition coat
should NOT be exposed, since it provides essential corrosion protection.

7. Apply a quality urethane enamel color coat or base coat/clear coat as required for maximum
repair durability (lacquer-type paint is NOT recommended for this application). Follow the paint
manufacturer’s recommendations for detailed application of paint as required.
NOTE
Check with state and local ordinances regarding the use and disposal of all chemicals.

© 2024 Toyota Motor Sales, USA