Flange Surface Installation Note

WARNING: This page is about a different car, the 2020 Mazda MX-5 Miata. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION:

If the TWC or main silencer is reused, sand the flange surface and remove sanding residue, accumulated matter, and friction marks before installing the seal ring.
If this work is not performed, the seal ring may not be installed correctly. When sanding the flange surface, be careful not to damage the surface.
When sanding the flange surface, sanding residue may get into the removed part or pipe resulting in deterioration or damage to the part. When sanding, make sure parts are protected from sanding residue or foreign matter penetration.

Sand the surface shown in the figure using sandpaper and remove sanding residue, accumulated matter, and friction marks.
Degrease the sanded surface.

Courtesy of MAZDA MOTORS CORP.