From the outside, the wheel arches looked great. Superficially, it did not seem like there was a lot of rust. In fact, the outer visible portion of the quarter panel had only minimum visible rust on the outside, and even after scrubbing it, only two minor rust holes appeared (barely visible in the picture below).
Looking at the inside of the wheel arch, there were fist-sized rust holes, so I masked off the paint and started cutting out the rust. To fix this properly, the outer wheel arch needed to be largely removed to allow proper access.
I tried to keep the cuts within the black area of the two-tone paint to avoid having to repaint the car.
While the outside still looked great, large parts of the inner wheel arch was rotten. Most part of the inner wheel arch were missing or weakened. At the part where the bumper was mounted to, road dirt and rain water entered the trunk through a hole.
Unfortunately, the inner wheel arch is not available as a reproduction piece, so I had to fabricate it myself. The tools that were most useful here were:
- A metalwork hammer and a sand bag.
- A stretch/shrink machine.
- Hand seam bending pliers.
- Magnets.
Restoring The Inner Wheel Arch
The inner wheel arch was too large to be made out of one piece, especially with the difficult curves. In the end, I recreated the inner wheel arch out of three pieces.
You need to have the outer wheel arch ready to test-fit the positioning and width of the inner wheel arch. In the end, the inner and outer arch need to fit together perfectly. If you are not doing this job properly, you will gaps or the outer panel may not fit at all.
You can see that I also did not manage to perfectly replicate the shape of the original wheel arch, as the repair piece is a bit flatter. However, I took great care that the width is correct, and the outer radius matches the outer arches.
The end area of the pockets is a rather straight shape, and fabricating the repair pieces at the bottom inner wheel arch is a bit easier. The pockets themselves are still in acceptable condition, and I decided to not cut any further.
Work has started on the second repair piece for the bottom inner wheel arch. Getting the inner fender to perfectly align with the outer fender is challenging.
Bottom inner side repair completed.
Repairing The Outer Wheel Arch
With the inner fender completed, the area was painted. I also applied Sikaflex body panel adhesive to strengthen the connection, noise isolation and sealing between the inner and outer fender.
The outer wheel arch in the process of being welded on. Similar to OEM, the outer and inner wheel arch are welded together using spot welds on the bottom seam.
The welding work is now almost completed. The outer wheel arch was made using three parts: the left and right piece are still the original metal that I put back after removing the surface rust, and the middle part was fabricated. I did not use a repair piece.
After the welding work was completed, I used corrosion protection grease to seal the cavity on the inside. I usually use Mike Sanders for this, but it is not available in Japan. I therefore used a homemade solution (90/10 mix of Vaseline with bee wax). Since this is mostly clean and new metal, wax would also work.
All that’s still left to do is to grind down the welds, a thin layer of body filler, and a local respray.
