E46 M3 Rear Subframe Reinforcement: Part 3

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E46 M3 Rear Subframe Reinforcement: Part 3

In continuation of part 2, part 3 covers the welding of the Redish plates underneath the RACP, cracks from the RACP separation and finishing work.

Step 1: Prepare bottom of rear axle carrier panel for reinforcement plates.

The cracks on the bottom mounts were stop drilled, beveled, and welded before being ground smooth for the reinforcement plates.

Step 2: Weld Redish V2 reinforcement plates to RACP.

The plates for the front mounts were welded on.


The spacer plates were tacked into place after the front mount reinforcement plates were welded. The bolts were installed to ensure proper alignment of the plates.

The rear reinforcement plates were then fitted and welded.

Step 3: Prepare and weld RACP separation cracks at wheel arch.

The rear axle carrier panel tends to separate at the driver’s side rear wheel arch and requires stitch welding to repair.

The seam sealer was ground away to reveal fresh metal.

No pictures were taken of the welding repair. Several stick welds were placed on the outside of the arch lip and the spot welds on the inside of the lip were reinforced.

Step 4: Prime and paint, seam seal, and finish all welded areas.

After welding of all of the reinforcements were completed the areas were finished with 2K epoxy primer, paint, seam sealer, and cavity wax. First, all areas were primed with 2K epoxy.

After the 2K epoxy primer was applied all areas were prepped for seam sealer.

Seam sealer was then applied and after drying 2K epoxy primer was sprayed over the seam sealer. On the bottom reinforcements SEM EZ coat olive green paint was sprayed over the primer. On the top reinforcements and wheel arch Imola Red paint was sprayed followed by 2K clear coat.

New BMW sound deadener was installed to replace what was removed in the trunk area.

After reinstalling the interior and rear drivetrain an alignment was completed.

Wondering where this started? Check out Part 1 and Part 2 of the E46 M3 Rear Subframe Reinforcement.

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