Repair of defects in aluminum wheels (Audi 100 C4)

Table of contents: Restoration of protective coating of… ↓ General processing sequence ↓

Remove the wheel from the car.

Locate air leaks by inflating the tire to 345 kPa and immersing the wheel in a container of water.

Mark the leaky areas and remove the tire from the wheel.

Treat the inner surface of the wheel in the defective area with sandpaper and then clean the treated area with a universal detergent.

Apply a 3.3mm sealing patch to the defective area and wait 12 hours until the adhesive is completely dry.

Install the tire on the wheel, inflate it to a pressure of 345 kPa and check the wheel for leaks.

Bring the air pressure in the tire to normal.

Balance the wheel.

Install the wheel assembly onto the vehicle.

Tighten the wheel mounting bolts using a torque wrench to 90 Nm.

Restoration of protective coating of aluminum wheels

Aluminum cast wheels have a transparent or colored protective coating. If the integrity of the protective coating is damaged, the wheel material begins to deteriorate. The protective coating can be damaged in a mechanized car wash, where brushes with hard tips are used to wash the sidewalls of tires. Unprotected wheel material is destroyed by caustic detergents and salt compounds used to treat roads in winter. The technology for restoring the coating of aluminum wheels is described below. Necessary tools and materials:

Arnchlen Alumi Prep N33 (#DX533) Aluminum Cleaner and Conditioner or equivalent.
Arnchem Alodine N1001 (No. DX50T) Aluminium Coating or equivalent.
Acrylic urethane coating for aluminum Ditzier Delclear Acrylic Urethane Clear (No. DAU-75) or equivalent. Ditzier Delthane Ultra-Urethane Additive (DXR-80) or equivalent.

General processing sequence

Mark the location of the wheel on the vehicle and the holes for the mounting bolt.

Remove the wheel from the car.

Mark the position of the balancing weights and remove them from the wheel.

Wash the outer and inner surfaces with an aqueous solution of a universal detergent. Remove traces of grease and oil with a solvent.

Cover the tire with a screen to prevent drips of coating from getting in.

Depending on the specific case, select and perform one of two repair procedures: "Removing damage to the aluminum wheel material" or "Removing damage to the clear protective coating of unpainted wheels".

Install the balancing weights with nylon coated clamps in place.

Install the wheel and tire assembly on the vehicle and tighten the mounting bolts to a torque of 90 Nm.

Pre-treatment of damaged areas of the color coating

Sand with 40 grit sandpaper (dry or wet) damaged areas of the color coating to ensure better adhesion of the wheel surface to the clear protective coating.

Repairing damage to aluminum wheel material

Place the wheel and tire assembly on the stand hub and turn on the slow rotation speed.

Grind off defects in the wheel material using sandpaper stretched over a block of suitable shape. During processing, slowly move the block with sandpaper over the surface of the wheel being processed. Processing begins with coarse sandpaper, then continues with medium-grain sandpaper and ends with fine sandpaper. The following sequence is recommended: