Body maintenance and repair (Audi A6 C4)

The condition of your car's body is very important because it largely determines its resale value. It is much more difficult to repair a neglected or damaged body than mechanical parts. Hidden body cavities such as wheel wells, frame and engine compartment are also no less important, despite the fact that they do not require as much attention as other parts of the body.

Once a year, or every 20,000 km, it is very useful to clean the underbody with steam. All traces of dirt and oil will be removed, and then the area can be checked for rust, damaged brake lines, worn electrical wires, damaged cables, etc. At the end of this work, the front suspension components should be lubricated.

At the same time, clean the engine and engine compartment with a steam cleaner or grease remover.

Particular attention should be paid to the wheel wells, as the underlay can peel off and stones and dirt thrown up by the wheels can damage the paint and allow rust to set in. If you find rust, sand the damaged area down to the bare metal and apply anti-corrosion paint.

The bodywork should be washed at least once a week. Wet the car thoroughly to soften the dirt, then rinse it off with a soft sponge and plenty of soapy water. If dirt is not rinsed off thoroughly, it can rub off the paint.



Tar or bitumen stains should be cleaned with a cloth soaked in solvent.

At least every six months, polish the body and chrome parts. If you use chrome cleaner to remove rust from plated parts, remember that the cleaner also removes the chrome, so use it with caution.

Vinyl finish

Never clean vinyl trim with detergents, caustic soaps, or kerosene-based cleaners. Plain soap and water work just fine, and a soft brush can easily remove stubborn dirt. Wash vinyl trim as often as you would the rest of your car.

After cleaning, applying a high-quality rubber and vinyl protectant will help prevent oxidation and cracking. Protective agents can also be applied to window seals, vacuum lines, and rubber hoses, which often fail due to chemical degradation, as well as tires.

Upholstery and carpets - care

Every three months, remove the mats and clean the inside of the car (if necessary, do this more often). Use a vacuum cleaner to clean the upholstery and carpets to remove any remaining dirt and dust.

Leather upholstery requires special attention. Stains should be removed with warm water and a very mild soap solution. Use a clean cloth to remove the soap, then wipe the upholstery again with a dry cloth. Never use alcohol, gasoline, nail polish remover, or thinner to clean leather upholstery.

After cleaning, regularly treat the leather upholstery with a special wax. Never use car wax to polish leather upholstery.

Where the vehicle interior is exposed to sunlight, cover leather seats with sheets if the vehicle will be left in the sun for any length of time.

Repair of small scratches

If the scratch is superficial and does not affect the body metal, the repair is very simple. Lightly rub the scratched surface with a fine polishing compound to remove loose paint and wax. Rinse the surface with clean water.

Apply touch-up paint to the scratch using a small brush. Continue applying thin coats of paint until the scratch is completely filled. Allow the new paint to dry for at least two weeks, then blend it with the surrounding paint by buffing the painted area with a fine polishing compound. Finally, apply a top coat of wax to the scratched area.

If the scratch has penetrated the paint and damaged the metal body, causing rust, a different repair procedure is necessary. Remove the rust from the base of the scratch with a pocket knife, then apply rust-preventing paint to prevent future rust. Using a rubber or nylon applicator, coat the scratched area with glaze (glaze is a semi-transparent paint layer). Before the glaze in the scratch hardens, place a piece of smooth cotton cloth around the tip of your finger. Dip the cloth in thinner, then quickly run it around the surface of the scratch. This will help you ensure that the surface of the glaze is slightly sunken. You can now paint over the scratch.

Warning: If necessary, the glaze can be mixed with thinner to make a very thin putty that is ideal for filling narrow scratches.

Dent repair

When performing dent repair, the first thing to do is to straighten the dent so that the damaged area is as close to the original shape as possible. There is no point in trying to completely restore the original shape, since the metal in the damaged area is stretched and cannot be restored to the original contour. It is better to level the dent so that its level is approximately 3 mm below the level of the surrounding metal.



If the dent is very small, there is no point in straightening it out at all.

Warning: Hold a block of wood firmly against the back of the metal to absorb the hammer blows and prevent stretching of the metal.

If the dent is in a part of the body that has a double layer, or something else makes it impossible to access from the inside, a different procedure must be used. Drill several small holes in the metal inside the damaged surface, preferably in the deepest parts. Screw long, self-tapping screws into the holes so that they engage firmly with the metal. Now you can straighten the dent by pulling on the protruding heads of the screws with pliers.

The next step in the repair is to remove paint from the damaged area and the surrounding metal by about an inch. This is done with a wire brush or a sanding disc attached to a drill, but can be done by hand with sandpaper with equal efficiency. To complete the preparation for the filler, use a screwdriver or file to smooth the exposed metal surface, or drill small holes into the damaged area. This will ensure good adhesion of the metal and the glaze.

Repairing rust holes or cracks

Remove all paint from the damaged area and the surrounding metal within a radius of approximately 2.5 cm using sandpaper or a wire brush attached to a drill. If these are not available, this job can be done by hand using several sheets of sandpaper.

Once the paint is removed, you can determine the extent of the corrosion and decide whether to replace the entire panel or, if possible, repair the damaged area. New body panels are not as expensive as many people think, and it is often much faster to install a new panel than to repair a large area damaged by rust.



Remove all trim pieces from the damaged area, except for those that act as a guide to the original shape of the damaged car body, such as the headlight housing, etc. Using metal shears or a hacksaw blade, remove all damaged metal, as well as any other metal that shows signs of rust. Use a hammer to bend the edges of the hole inward to create a small recess for the filler material.

Use a wire brush to scrub the damaged area to remove powdery rust from the metal surface. If the back of the rusted surface is accessible, coat it with rust-preventing paint.

Before final sealing, plug the hole in some way. This can be done with sheet metal riveted or screwed into the hole, or wire mesh can be installed in the hole.

Once the hole is plugged, the damaged area can be filled and painted over.

Filling and painting

There are many body repair fillers available today, but honestly, a body repair kit that contains a filler paste and a tube of polymer hardener is best for repair work. You will need a wide flexible plastic or nylon applicator to smooth out the surface of the filler. Mix a small amount of filler mixture on a clean piece of wood or cardboard (using hardener sparingly). Follow the manufacturer's instructions on the package or the filler will not cure properly.

Using the applicator, apply the filler paste to the prepared surface. Run the applicator over the surface of the filler to achieve the desired contour and level the surface of the filler. When the initial level and contour are achieved, stop working with the paste. If you continue, the paste will stick to the applicator. Continue applying thin layers of paste at 20-minute intervals until the filler level exactly matches the level of the surrounding metal.



Once the filler has hardened, you can remove any excess with a file. Next, use sandpaper, gradually increasing its grain size, starting with 180 grit paper and ending with 600 grit waterproof paper. Always wrap the sandpaper around a rubber or wooden block, otherwise the filler surface will not be completely flat. When sanding the filler surface, the 600 grit waterproof sandpaper should be periodically moistened with water. This will help achieve a very smooth surface.

The repair area should now be surrounded by a ring of bare metal, which in turn should be surrounded by good, undamaged paint. Rinse the repair area with water until all the dust remaining from sanding is removed.

Apply a thin coat of primer to the entire cleaned surface. This will help reveal any defects on the filler surface. Correct any defects with fresh filler or glaze and sand the surface again. Repeat the primer and filler application until you are satisfied with the quality of the filler surface and the paint edge. Rinse the surface with clean water and allow it to dry completely.

The repair area is now ready to be painted. Spray painting should be done in warm, dry, windless weather with no dust in the air. These conditions can be achieved if you have access to a large workshop. However, if you will be working outdoors, you must choose your painting day very carefully. If you are working indoors, spray the floor with water. This will help to knock down dust that may otherwise become airborne. If the repair area is on one body panel, cover all surrounding panels. This will help to minimize minor mismatches in paint color. Decorative trim pieces such as chrome trim, door handles, etc. should also be masked or removed. Use masking tape and several layers of paper to mask them.



Before spraying, shake the paint thoroughly and then practice spraying it to learn how to do it correctly. Apply a thick coat of primer to the surface to be repaired. It is better to apply several thin coats than one thick one. Using 600 grit sandpaper, sand the surface of the primer until it is very smooth. During this operation, the surface to be treated must be thoroughly wetted with water. The sandpaper must also be dipped in water periodically. Allow the primer to dry before applying additional coats.

Spray paint onto the top coat, building up the thickness by applying several coats. Start spraying from the center of the repair area, then using circular motions, spray the entire repair area and approximately 5 cm of surrounding paint. Remove all masking material 10 to 15 minutes after applying the last coat of paint. Allow the new paint to dry for at least two weeks, then use a very fine sanding compound to blend the new paint into the original paint. Finish with a coat of wax.

Body repair - significant damage

Significant damage to the body must be repaired at service stations that have equipment for body repair.

If there is extensive damage, the body geometry should be checked. It may also affect the handling characteristics of the car or cause other components to wear out faster.

Due to the fact that all the main components of the body (hood, fenders, etc.) are separate elements that can be replaced, it is best to replace them rather than repair them. Sometimes the required parts can be found in used parts stores, which is much cheaper than buying new ones.

Hinges and locks - maintenance and repair

Every 5,000 km or every three months, apply a few drops of light oil or lock lubricant to the hinges and latches on the doors, bonnet and trunk. The door lock latches should also be coated with a thin layer of grease to reduce wear and ensure free movement. Lubricate the door and bonnet locks with graphite grease.

Windshield and fixed glass - replacement

Replacing the windshield and fixed glass requires the use of a special fast-curing adhesive or sealant and some specialized equipment. It is recommended that these operations be performed at service stations.