Discovery 2. Manual - part 278
CORROSION PREVENTION AND SEALING
CORROSION PREVENTION
77-4-7
The checks described above are intended to be visual only. It is not intended that the operator should remove trim
panels, finishers, rubbing strips or sound-deadening materials when checking the vehicle for corrosion and paint
damage.
With the vehicle on a lift, and using an inspection or spot lamp, visually check for the following:
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Corrosion damage and damaged paintwork, condition of underbody sealer on front and rear lower panels, sills
and wheel arches;
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Damage to underbody sealer. Corrosion in areas adjacent to suspension mountings and fuel tank fixings.
NOTE: The presence of small blisters in the underbody sealer is acceptable, providing they do not expose bare metal.
Pay special attention to signs of damage caused to panels or corrosion protection material by incorrect jack
positioning.
WARNING: It is essential to follow the correct jacking and lifting procedures.
With the vehicle lowered, visually check for evidence of damage and corrosion on all visible painted areas, in
particular the following:
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Front edge of bonnet;
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Visible flanges in engine compartment;
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Lower body and door panels.
Rectify any bodywork damage or evidence of corrosion found during inspection as soon as is practicable, both to
minimise the extent of the damage and to ensure the long term effectiveness of the factory-applied corrosion
prevention treatment. Where the cost of rectification work is the owner's responsibility, the Dealer must advise the
owner and endorse the relevant documentation accordingly.
Where corrosion has become evident and is emanating from beneath a removable component (e.g. trim panel,
window glass, seat etc.), remove the component as required to permit effective rectification.
Underbody protection repairs
Whenever body repairs are carried out, ensure that full sealing and corrosion protection treatments are reinstated.
This applies both to the damaged areas and also to areas where protection has been indirectly impaired, as a result
either of accident damage or repair operations.
Remove corrosion protection from the damaged area before straightening or panel beating. This applies in particular
to panels coated with wax, PVC underbody sealer, sound deadening pads etc.
WARNING: DO NOT use oxy-acetylene gas equipment to remove corrosion prevention materials. Large
volumes of fumes and gases are liberated by these materials when they burn.
NOTE: Equipment for the removal of tough anti-corrosion sealers offers varying degrees of speed and effectiveness.
The compressed air-operated scraper (NOT an air chisel) offers a relatively quiet mechanical method using an
extremely rapid reciprocating action. Move the operating end of the tool along the work surface to remove the material.
The most common method of removal is by means of a hot air blower with integral scraper.
Another tool, and one of the most efficient methods, is the rapid-cutting 'hot knife'. This tool uses a wide blade and is
quick and versatile, able to be used easily in profiled sections where access is otherwise difficult.
Use the following procedure when repairing underbody coatings:
1 Remove existing underbody coatings
2 After panel repair, clean the affected area with a solvent wipe, and treat bare metal with an etch phosphate
material
3 Re-prime the affected area
CAUTION: DO NOT, under any circumstances, apply underbody sealer directly to bare metal surfaces.
4 Replace all heat-fusible plugs which have been disturbed. Where such plugs are not available use rubber
grommets of equivalent size, ensuring that they are embedded in sealer
5 Mask off all mounting faces from which mechanical components, hoses and pipe clips, have been removed.
Underbody sealer must be applied before such components are refitted
6 Brush sealer into all exposed seams
7 Spray the affected area with an approved service underbody sealer
8 Remove masking from component mounting faces, and touch-in where necessary. Allow adequate drying time
before applying underbody wax