Cosmetic repairs on rims

Precondition

Cost-effectiveness of the repairs has been checked.

1 - Arrangement of wheel rims

Type	Repair options
Cast aluminum wheel	see Point 2
Cast aluminum wheel (gloss-turned)	see Point 3
CFK rim	see Point 4

2 - Cast aluminum rim

In case of following damages, the rim must be replaced:

All types of deformations
All types of cracks
All damage deeper than 1 mm in the aluminum
All damages on the inner surface of the wheel rim and in the rim base
The radial runout and axial runout prior to preparation exceed the production tolerance of 0.3 mm

It is possible to repair the following damage:

Maximum depth of damage in the aluminum: 1 mm
The distance of the damage from the outer rim edge must not exceed 30 mm
Paintwork damage in area (1) can be repaired with paintwork.

Paintwork is not permitted in area (2).

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In the area (1), repairs on the substrate are permitted up to a depth of 1 mm.

If the aluminum in area (2) is damaged, the rim must be replaced.

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2.1.1 - Cast aluminum rim repair sequence

3 - Preparing rim

Disassemble tires.
Clean the aluminum rim with a steam jet.
Dry the aluminum rim.
Pre-grind the aluminum rim (break sharp edges with grain P180 grinding wheel).
Blow off the aluminum rim.
Clean large damaged areas with silicone remover.

2.1.1.1.2.1 - General information

CAUTION: Contact with hazardous substances.
Health impairment.

Note and comply with the Safety Instructions on the containers and the instructions on the manufacturer's safety data sheet.
Conduct all work in appropriate personal protective equipment only.

Filler S1
Processing time 20 °C	90 min
Processing time 30 °C	60 min
Curing time 60 °C	60 min
Storage	15°C... 25 °C
Shelf life (observe expiration date on the cartridge)	12 Monate

The binder can be extracted using a regular caulking gun. Only use caulking guns with a piston rod.

4 - See manufacturer's instructions/documents regarding rim repairs.

5 - Preparing the surface for the application of the filler

Grind surface to a metallic bright-finish.
For sheet steel, use grain 80.

For aluminum sheet, use grain 180.

The surface must be clean, dry and free from grease.
Clean the surface with a cleaning agent R2 and let it air out for 5 minutes.
Clean the surface with a cleaning agent R1 and let it air out for 2 to 3 minutes.

6 - Applying the filler

Fill area (1) with filler S1.
Apply filler S1 to excess.
Apply filler S1 in one pass if possible in order to prevent air pockets.

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7 - Hardening the filler

Harden filler S1.

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NOTE: TECHNICAL INFORMATION
Various devices can be used as desired.
Harden filler S1 using the "FlexiTherm" heating mat system.
Please comply with instructions in Owner's Manual.
Select the program in the control unit (5).

The control unit independently checks and adjusts the temperature of each individual heating mat (1).

These are separately activated. The temperature sensor is located on the inside (red side).

The heating mats may only be used in conjunction with the anti-adhesive paper (8).

For trouble-free temperature measurement, the sensor must always be placed on the filler (separated by anti-adhesive paper).

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Harden filler S1 with infrared beams.
NOTE:
RISK OF DAMAGE
Damage through overheating
When using temperature-controlled infrared radiators, damage to adhesive bonds, paint and vehicle parts can occur when drying spatula and filler. The thermometer integrated into the infrared beams function reliably only with large, even surfaces. On small surfaces such as C-pillars or sills, often only a colder, adjacent area is measured. This leads to actual surface temperatures of up to 130°C, even if only 70°C is set on the infrared radiator. When the rear walls are partially replaced by bonding and riveting, these high temperatures can lead to a visible pattern in the joint area.
- Check the surface temperatures on small component surfaces during the dry procedure with an external thermometer. The general rule is: The surface temperatures must not exceed 85°C.
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When the infrared heater is used for the first time, the correct distances that match the temperature must be determined.
Switch infrared beams on, continue changing the distance until the surface temperature of the filler does not change anymore over a time period of 2 min.

Use an infrared thermometer to measure the temperature.

When infrared thermometers are used (Epsilon value 0.92 to 0.95), the heater must be switched off briefly during the measurement.

Record the measurement
Standard infrared thermometers can be used to measure the surface temperature.

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8 - Processing the filler

CAUTION: Grinding dust from grinding of components.
Hazardous to health!

Directly draw off the grinding dust.
Ensure adequate ventilation.
Conduct all work in appropriate personal protective equipment only.

Wear a P2-P3 class fine dust mask.
After cooling down to 25 °C, grind the filler S1 using a grinding tool.
The maximum permitted layer thickness after grinding is 5 mm.

For sheet steel, use grain 80.

For aluminum sheet, use grain 180.
Pores and faulty spots that become visible after grinding the surface must be closed with polyester filler (BMW Color system).
Use aØ4.2 mm drill. Manually turn the drill to expand the pores in v shape. Fill cavities with polyester filler.
Clean the surface with a cleaning agent R2 and let it air out for 5 minutes.
Clean the surface with a cleaning agent R1 and let it air out for 2 to 3 minutes.

9 - Painting rim

Pre-grind for the filler application (grain P220 grinding wheel or superfine soft pad)
Blow off the aluminum rim.
Clean the aluminum rim with silicone remover.
Mask the aluminum rim, rim base and the contact surface of the hub.
Mask the rear of the rim flange.
Apply the filler.
Dry the filler.
Grind the filler (grain P400 grinding wheel).
Blow off the aluminum rim.
Clean the aluminum rim with hydro cleaner.
Mask the bolt holes.
Cleaning aluminum rim before base coat application.
Applying basic paint.
Dry base coat.
Applying clear coat.
Dry clear coat.

10 - Cast aluminum rim (gloss-turned)

In case of following damages, the rim must be replaced:

All types of deformations
All types of cracks
All damage deeper than 1 mm in the aluminum
All damages on the inner surface of the wheel rim and in the rim base
The radial runout and axial runout prior to preparation exceed the production tolerance of 0.3 mm

No cosmetic repairs on the aluminum are permitted.

Only the clear coating may be repaired on the entire front side of the wheel rim of diamond polished cast aluminum wheels.

Paintwork damage in area (1) can be repaired with paintwork.

Paintwork is not permitted in area (2).

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In area (1), damages on the aluminum up to a depth of 1 mm are acceptable.

From a technical point of view, there is no need to replace the rim.

If the aluminum in area (2) is damaged, the rim must be replaced.

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