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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   1. 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.
   1. 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. Repairing rim 
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).

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     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).

   • 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.
   1. 2.2 - 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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   2. 2.3 - CFK rims 

      No cosmetic repairs on the CFK rims are permitted.

      1. 2.3.1.1 - Evaluating damage to CFK rim 

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

         • All types of deformations
         • All types of cracks
         • Any damage deeper than 1 mm.
         • Radial run-out and axial run-out exceed production tolerance of 0.3 mm

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

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

         In case of damages in the area (2), the rim must be replaced.

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   Radial-running scratches (1) on the inner side (2) of the rim are acceptable up to a depth of 0.4 mm.

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

   The inner side of the rim (2) can be painted with matte black temperature-resistant paint.

   In case of scratches deeper than 0.4 mm, the rim must be replaced.

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10. Determining depth of scratch 
    • Gage has a test probe (1) with a height of 0.4 mm.
    • If the test probe sits up at the deepest point of the scratch (figure A), it can be shifted to the left and right. The scratch is less than 0.4 mm deep.
    • If the test probe dips so deeply into the scratch that the gauge sits flat (figure B), the scratch is deeper than 0.4 mm and the part is damaged.

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