BMW 7 Series: Opening Adhesive Bonds

1. Opening spot-weld bonds

OPEN WELD SPOTS.

WARNING: Extract vapors and gases.

Use personal protective clothing/equipment.

Heat connecting flange with a hot-air blower. Heat components to max. 250ºC object temperature.

Release connection flange with chisel.

Remove adhesive residue from connecting flange.

2. Opening adhesive bonds

If necessary, open existing PUNCH OR BLIND RIVETS.

Roughly cut out damaged component.

WARNING: Extract vapors and gases.

Use personal protective clothing/equipment.

Heat adhesive flange with a hot-air blower. Heat components to max. 250ºC object temperature.

The component can be peeled with the aid of pliers. Do not damage adjacent components.

Remove adhesive residue from connecting flange.

3. Opening adhesive bonds on aluminium roofs

Procedure is described in detailed in the relevant repair instructions.

4. Opening adhesive bonds on carbon-fibre-reinforced plastic parts

Procedure is described in detailed in the relevant repair instructions.

OPENING BRAZED JOINTS

The "Bonding and Riveting" repair method involves replacing the watertight brazed joint with adhesive.

This gives rise to a new procedure for opening brazed joints.

Grind brazed seam with a belt grinder. This keeps the influence of heat in the area around the brazed seam as small as possible.

IMPORTANT: Never use a gas flame.

All traces of brazing solder do not have to be removed.

Do not grind body panels thin.

OPENING RIVETED JOINTS

Different rivet types are used on BMW vehicles.

1. Opening blind rivets

1.1 Opening blind rivets (N1 and N2)

Grind off blind rivet head with a belt or angle grinder. Do not grind off base material. Remove rivet remnants with a drift punch.

1.2 Opening blind rivets (N3 and N6)

Drill out blind rivet head with a 5 mm dia. drill bit. Do not damage base material. Remove rivet remnants with a drift punch.

2. Opening punch rivets

2.1 Opening punch rivets by extraction

This procedure is used on the reduced-weight aluminium front end.

Recommended tools and equipment:

• Stud welding apparatus (refer to Service Information 5 03 03 975) with gas bottle containing inert gas (82 % argon, 18 % CO 2).
• Stainless steel stud (sourcing reference via BMW Parts Department picture board Aluminium and steel/bonding and welding)
• Universal riveting tool (refer to Service Information 5 03 03 975)

Grind off paint and dark grey coating of punch rivets.

Position bolt centrally on the rivet and weld on vertically. The area in which the bolts are welded on should be between the two grounding terminals. Position both terminals, if possible, on the top side of the metal plate on which the rivet is located.

Extract bolt with welded-on rivet using universal riveting tool. Use a large plastic nose piece if not otherwise specified in the repair instructions. Check plastic nose piece prior to use for wear.

Plastic nose piece must rest on sheet metal all round; if necessary, grind off plastic noise piece in collision area.

Do not push riveting tool forcefully onto special-steel bolts.

Do not use riveting tool to bend special-steel bolts.

Pay particular attention to central positioning of the bolt when using the small plastic mouthpiece.

Follow the equipment manufacturer's instructions for use.

2.2 Opening punch rivets by drilling out

Drill out rivets with a 6 mm dia. carbide drill bit.

Punch rivets can be drilled out on both sides. When drilling from the protruding rear side, spot-drill the rivet shank only and remove the rest with a rivet punch.

Use a drift punch to remove punch rivet remnants in the aluminium (risk of corrosion).

Clean vehicle to remove chips (risk of corrosion).

OPENING WELD JOINTS

1. Opening weld spots (resistance pressure spot welding)

Sheet steel panels made from high- and super-high-strength materials make great demands on the tools used.

Only with special carbide milling cutters can weld spots be drilled out on these sheet panels.

Procedure

If necessary, surface-grind existing unevenness with a belt or angle grinder in the area around the weld spot.

Set punch mark in center of weld spot. Set 8 mm dia. weld spot drill bit on punch mark and drill through top metal sheet.

NOTE: Because the weld spots may have surface-hardened, grind them if necessary with an angle grinder and paper grinding disk.

Use a chisel to separate the sheet metal flange and remove the component.

Follow the special procedure for SPOT WELDS.

2. Opening MAG weld seams and MIG brazing seams

Procedure

Grind off weld seams with a belt or angle grinder. Do not grind the base material thin.

Use a chisel to separate the sheet metal flange and remove the component.

3. Opening laser weld seams

Laser weld seams are used in the roof outer skin area.

Procedure

Roughly cut roof outer skin in the roof channel to improve accessibility.

Place angle grinder with grinding disc on laser weld seam and grind through top metal sheet. Be careful not to cut through and damage sheet metal underneath.

Remove sheet metal flange.

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