BMW X3 Service & Repair Manual: Opening welded connections

1. Components made of steel:

1.1 Opening welding 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 welding spots be drilled out on these sheet panels.

Use BTR/BOR milling cutters only in conjunction with Vario Drill spot-weld remover. Sourcing reference for spot-weld remover and BTR/BOR milling cutters.

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

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

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

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

Follow the special procedure for SPOT WELDS.

1.2 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.

1.3 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.

2. Components made of aluminum:

2.1 Opening MiG weld seams:

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

  Do not use a chisel.

  Remove component.