Mitsubishi Evolution X. Manual — part 10

CORROSION PROTECTION

TSB Revision

BASE OF BODY REPAIR

9-37

CORROSION PROTECTION

ANTICORROSION TREATMENT AT THE FACTORY

M4090019000064

Anticorrosion treatment at the time of production
includes the following measures.

THE USE OF GALVANIZED STEEL PLATE

Because galvanized steel plate has excellent corro-
sion resistance, it is used in areas which have a high
possibility of painting deficiency.

ZINC PHOSPHATE COATING

In order to improve the adhesive properties of the paint coat on
the steel plate, and also to improve the finish of the paint coat,
the entire body is coated with a film of zinc phosphate prior to
undergoing the electrodeposition undercoating process.

1. Final coat
2. Intermediate coat
3. Anticorrosion primer
4. Undercoat
5. Zinc phosphate film
6. Steel plate

AB200136 AB

: locations where galvanized steel
plate is used.

AB200109

1

2

3

4
5

6

CORROSION PROTECTION

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BASE OF BODY REPAIR

9-38

CATIONIC ELECTRODEPOSITION UNDERCOATING

In the cationic electrodeposition method, the car
body is the negative pole, thus preventing damage to
the zinc plating of the galvanized body panels or to
the chemically formed phosphate crystals. This
method, therefore, maximizes the corrosion resis-
tance and the results obtained are much better than
those from conventional anionic electrodeposition.

BODY SEALING

Sealant has been applied to all body panel joints and seams in
order to provide resistance to water, dust, and corrosion.

UNDERBODY COATING

An underbody coating has been applied to the underside of the
floor pans, the inside of the doors, etc., in order to provide
resistance to vibration, corrosion, and wear.

AB200110AD

Anionic electrodeposition

Counteragent

Anionic
coating

Counteragent

Alkali
solution

Cationic electrodeposition

Cationic
coating

AB200110

AB301462

A

A

SECTION A – A

AB

AB200112

CORROSION PROTECTION

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BASE OF BODY REPAIR

9-39

WAX INJECTION

Wax injection is used at the lower part of the frame, side sill and
hollow panels, etc., in order to obtain a better anticorrosion
effect.

ANTICORROSION PRIMER

Anticorrosion primer is used at the side sill outer pan-
els in order to prevent corrosion and to suppress
vibration.

SEALING TAPE

Sealing tape is attached at unused holes, at the inner side of
the panel, for waterproofing and anticorrosion protection.

AB200113

AB701034

1. Rocker panel primer application

AB

1

1

A

A

AB701034

AB301463 AF

AB301463

: Locations for

attachment of sealing tape

CORROSION PROTECTION

TSB Revision

BASE OF BODY REPAIR

9-40

ANTICORROSION TREATMENT AT THE TIME OF
BODY REPAIR WORK

M4090020000046

The following procedures should be followed for anticorrosion
protection when making repairs.

CORROSION PROTECTION FOR HOLLOW
PARTS

CAUTION

• Wipe away any excess anticorrosion agent on the

coated surface, because it can adversely affect the
coating.

• When spraying the anticorrosion agent, use holes in

different areas to ensure that all weld surfaces of the
hollow structure are well coated.

The insides of hollow parts (such as the side sill, pillars, etc.)
which have been welded are more susceptible to corrosion.
Spray an aerosol-type anticorrosion agent into these parts by
using the trim mounting holes and other openings.

ANTICORROSION TREATMENT OF ROUGH CUTS

An anticorrosion agent should be applied to rough cuts made in
the course of welding, because the surface film has been dam-
aged by the heat of welding.

SPOT SEALER

In order to prevent corrosion from occurring at the contact sur-
faces of panels which are spot welded, apply an electroconduc-
tive spot sealer.

.

SPOT SEALER APPLICATION STEPS

1. Remove all paint, etc., from the areas to be spot welded by

using sandpaper or a pneumatic belt sander.

AB200116

AB200117

AB200118