BMW 7 Series: Installing A Cavity Acoustic Baffle (Expanded)

NOTE: Carry over schematic representation to the relevant vehicle type.

Before these work steps, prepare the new part so that it is ready to install (adapting, cutting to size, applying welding primer etc.).

Clean contact surface (1) with cleaning agent R2.

Apply a bead (2) approx. 15 mm high of SEALANT D1 to contact surface (1).

In order to avoid run off of the sealant when bonding to a vertical surface, a thin coat of sealant on both sides of the surface may be necessary.

Fit, secure and weld up new part.

Fig. 25: Identifying Contact Surface Sealant Applying Area

WARNING: Ensure adequate ventilation over entire processing period.

NOTE: Carry over schematic representation to the relevant vehicle type.

Before these work steps, prepare the new part so that it is ready to install (adapting, cutting to size, applying welding primer etc.).

Sand contact surface of cavity acoustic baffle (1) with coarse-grained sandpaper (grain 50-100).

Clean contact surface (1) with cleaning agent R2.

Apply a bead approx. 15 mm high of SEALANT D1 to contact surface (1).

If necessary apply sealant D1 somewhat thinner on each side, to prevent the sealant from running.

Attach cavity bulkhead in specified position (see old part).

Fit, secure and weld up new part.

Fig. 26: Identifying Contact Surface Sealant Applying Area

WARNING: Ensure adequate ventilation over entire processing period.

INSTALLING A CAVITY SEALING WITH 2-COMPONENT PU CAVITY FOAM

Sourcing reference for cavity foam (refer to BMW Parts Department).

IMPORTANT: The cavity foam may only be use for cavity sealing at the points at which cavity sealing is present as standard!

The following repair represents the replacement of a shaped part for the cavity sealing by the use of cavity foam.

This type of cavity sealing is used at points at which shaped parts cannot be used for repairs.

This is the case when large amounts of heat occur (e.g. due to welding, soldering or tin-plating) in the direct vicinity or at the point of the standard cavity sealing.

It is not possible here to install shaped parts for the cavity sealing because of the fire risk! To replace shaped parts with cavity foam at further locations, adopt the procedure shown here and adapt it to the relevant ratios.

It must be ensured that the cavity is completely sealed off.

NOTE: Check the accessibility for the spraying pipe of the cavity foam to the affected cavity after removing the defective parts.

Properties of cavity foam:

• 2-component PU foam, solvent-free.
• Excellent flow capacity, enabling complete sealing of cavities.
• Good strength, preventing slipping in cavities.
• Low water absorption, preventing corrosion.
• Ideal for use as insulating and sealing compound.

Information on dangers/hazards

• Avoid eye and skin contact.

  Wear eye protection, solvent-resistant protective gloves and protective clothing.

• Do not inhale.

  Apply in well ventilated rooms only.

WARNING: Application time after mixing: within 8 minutes!

• Completely empty open can after use.
• Residual amounts which are not used can cause the can to explode on account of a chemical reaction (buildup of heat)! Alternatively, cool the can containing the non-removed residual amount for several hours in cold water.
• Do not eat, drink or smoke while working with these products.
• Keep heat and ignition sources well away.
• Read the manufacturer's information on hazards/dangers (printed on the can) prior to application.

Processing instructions

• Observe the expiry date on the cartridge.

  Do not use the spray can after the expiry date on the can has expired. After the Use by date the properties of the cavity foam will no longer meet the requirements of the BMW Group.

• Cavity sealing of repair area possible after an air drying time of 1 hour.
• Backing surface must be
  clean and free from
  dust,
  grease,
  oil and stripping agent.
• Application temperature at least 15ºC. Optimally 20ºC.
• IMPORTANT: Foam expands many times over as it sets (change in volume).
• Before applying to the vehicle, fill a clearly visible cavity of corresponding size with foam on a used part.

  This enables an optimal dosage (i.e. spraying time) to be specified for filling the cavity on the vehicle with foam.

• Tape off open passages to visible areas with adhesive tape to prevent foam from escaping.
• Setting takes approx. 30 minutes. Mechanical processing (e.g. drilling, cutting, etc.) is then possible.
• Cavity sealing of repair area possible after an air drying time of 1 hour.
• Remove fresh, non-hardened PU foam with adhesive cleaner 208.

  Sourcing reference: BMW Parts Department.

  Hardened PU foam can only be removed by mechanical means (machine).

• Excess, hardened PU foam can be disposed of as residual waste.

  Cans which are not entirely empty and unused whose expiry date has expired are classed as hazardous waste.

  Observe country-specific waste disposal regulations.

• Observe the manufacturer's processing instructions (printed on the can).

MATERIALS SCIENCE

1. Aluminum

1.1 Chassis and suspension components

Read and observe the NOTES ON CHASSIS AND SUSPENSION COMPONENTS before handling aluminum.

1.2 Material influences

MATERIAL INFLUENCES CHART

1.3 Machining properties

MACHINING PROPERTIES CHART

1.4 Mounting

MOUNTING CHART

READ NEXT: