CORROSION PREVENTION AND SEALING
CORROSION PREVENTION 77-4-5
Corrosion Prevention
The following information details Corrosion Prevention treatments.
Factory treatments
During production, vehicle bodies are treated with the following anti-corrosion materials:
lAn application of cavity wax which is sprayed into the sill panels and the lower areas of the door panels.
lA PVC-based underbody sealer which is sprayed onto the underside of the main floor and sills, the exterior of
the safe well and the forward face of the lower dash crossmember.
lA coating of underbody wax which is applied to the entire underbody inboard of the sill vertical flanges, and
covers all moving and flexible components EXCEPT for wheels, tyres, brakes and exhaust.
lA coat of protective wax applied to the engine bay area.
Whenever body repairs are carried out, ensure the anti-corrosion materials in the affected area are repaired or
renewed as necessary using the approved materials.
Cavity wax injection
Areas treated with cavity wax are shown in the following 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:
lComplete all paint refinish operations before wax application.
lClean body panel areas and blow-clean cavities if necessary, before treatment.
lMaintain a temperature of 18°C during application and drying.
lCheck the spray pattern of injection equipment.
lMask off all areas not to be wax coated and which could be contaminated by wax overspray.
lRemove body fixings, such as seat belt retractors, if contamination is at all likely.
lMove door glasses to fully closed position before treating door interiors.
lTreat body areas normally covered by trim before refitting items.
lCheck that body and door drain holes are clear after the protective wax has dried.
lKeep all equipment clean, especially wax injection nozzles.
CORROSION PREVENTION AND SEALING
77-4-8 SEALING
Underbody sealer
Underfloor areas and sill outer panels are treated with a Plastisol PVC underbody sealer. This material is not suitable
for re-treatment. When repairing areas of underbody sealer, strip the factory-applied underbody sealer back to a
suitable break point. Ensure that a clean metal surface is exposed and that the edge of the existing sealer adheres
soundly to the panel.
Apply new underbody sealer between primer and surfacer paint operations. Apply seam sealer as necessary before
application of underbody sealer. Ensure that blanking plugs and grommets in the floor pan (except those used for wax
injection) are fitted before underbody sealer application. Refit any heat-fusible plugs which have been disturbed in
repair with the aid of a hot air blower, or replace with rubber grommets.
caut : Ensure that suspension units, wheels, tyres, power unit, driveshafts, exhaust and brakes (including all mounting
points) are shielded prior to application of fresh underbody sealer.
Underbody wax
The underbody wax must be reinstated following all repairs affecting floor panels. The wax is applied over paints and
underbody sealers.
caut : Remove old underbody wax completely from a zone extending at least 200mm 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.
Precautions during body repairs and handling
Take care when handling the vehicle in the workshop. Underbody sealers, seam sealers, underbody wax and body
panels may be damaged if the vehicle is carelessly lifted.
Proprietary anti-corrosion treatments
The application of proprietary anti-corrosion treatments in addition to the factory-applied treatment could invalidate
the Corrosion Warranty and should be discouraged. This does not apply to approved, compatible, preservative waxes
which may be applied on top of existing coatings.
Fitting approved accessories
When fitting accessories ensure that the vehicle's corrosion protection is not affected, either by breaking the protective
coating or by introducing a moisture trap.
Do not screw self-tapping screws directly into body panels. Fit suitable plastic inserts to the panel beforehand. Always
ensure that the edges of holes drilled into panels, chassis members and other body parts are protected with a suitable
zinc rich or acid etch primer, and follow with a protective wax coating brushed onto the surrounding area.
Do not attach painted metal surfaces of any accessory directly to the vehicle's bodywork unless suitably protected.
Where metal faces are bolted together always interpose a suitable interface material such as weldable zinc rich
primer, extruded strip, or zinc tape.
Steam cleaning and dewaxing
Due to the high temperatures generated by steam cleaning equipment, there is a risk that certain trim components
could be damaged and some adhesives and corrosion prevention materials softened or liquified.
Adjust the equipment so that the nozzle temperature does not exceed 90°C (194°F). Take care not to allow the steam
jet to dwell on one area, and keep the nozzle at least 300mm from panel surfaces.
DO NOT remove wax or lacquer from underbody or underbonnet areas during repairs. Should it be necessary to
steam clean these areas, apply a new coating of wax or underbody protection as soon as possible.
