Toyota Corolla Front Mud Flap Mount Reinforcement Backer Plate

When replacing the front wheel fender liner on my 2006 Toyota Corolla, I encountered that the front mud flap, which is attached to the linter by two M6 bolts, needs a backer plate on the inside of the liner. The original backer plate was made of steel, and it rusted all the way through, plus the original bolts rusted and fused into it, to the point that they would need to be drilled out to be removed.

I printed a replacement backer plate with ABS (must use a heat-stable resin for car parts).

I replaced the metal hardware with stainless: two M6x20mm bolts, four 20mm diameter M6 washers, and two M6 Nyloc nuts.