CORROSION PREVENTION (page 3 of 3)

CORROSION PREVENTION AND SEALING

77-4-8

CORROSION PREVENTION

After refitting mechanical components, including hoses and pipes and other fixtures, mask off the brake discs and 
apply a coat of approved underbody wax.

NOTE: Where repairs include the application of finish paint coats in the areas requiring underbody wax, carry out paint 
operations before applying wax.

Cavity wax injection
Areas treated with cavity wax are shown in the previous figures. After repairs, always re-treat these areas with an 
approved cavity wax. In addition, treat all interior surfaces which have been disturbed during repairs whether they 
have been treated in production or not. This includes all box members, cavities and door interiors. It is permissible to 
drill extra holes for access where necessary, provided these are not positioned in load-bearing members. Ensure that 
such holes are treated with a suitable zinc rich primer, brushed with wax and then sealed with a rubber grommet.

Before wax injection, ensure that the cavity to be treated is free from any contamination or foreign matter. Where 
necessary, clear out any debris using compressed air.

Ensure that cavity wax is applied AFTER the final paint process and BEFORE refitting any trim components.

During application, ensure that the wax covers all flange and seam areas and that it is adequately applied to all 
repaired areas of both new and existing panels.

It should be noted that new panel assemblies and complete body shells are supplied without wax injection treatment. 
Ensure that such treatment is carried out after repairs.

Effective cavity wax protection is vital. Always observe the following points:

l

Complete all paint refinish operations before wax application;

l

Clean body panel areas and blow-clean cavities if necessary, before treatment;

l

Maintain a temperature of 18

°

 C (64

°

 F) during application and drying;

l

Check the spray pattern of injection equipment;

l

Mask off all areas not to be wax coated and which could be contaminated by wax overspray;

l

Remove body fixings, such as seat belt retractors, if contamination is at all likely;

l

Move door glasses to fully closed position before treating door interiors;

l

Treat body areas normally covered by trim before refitting items;

l

Check that body and door drain holes are clear after the protective wax has dried;

l

Keep all equipment clean, especially wax injection nozzles.

Underbody wax
The underbody wax must be reinstated following all repairs affecting floor panels. The wax is applied over paints and 
underbody sealers.

Remove old underbody wax completely from a zone extending at least 200 mm (7.874 in) beyond the area where new 
underbody sealer is to be applied.

Engine bay wax
Reinstate all protective engine bay wax disturbed during repairs using an approved material.

Where repairs have involved replacement of engine bay panels, treat the entire engine compartment including all 
components, clips and other fixtures with an approved underbonnet lacquer or wax.
 

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 BODY SEALING MATERIALS, MATERIALS AND APPLICATIONS, Approved materials.