First job is to dig out all the underseal, kill any rust and repaint the metal. I found the best process was to slit it with a stanley knife into long strips the dig them out with a screwdriver. then get the rest of with a wire wheel in a drill.
On the corrado near the front of the arch there's 3 tabs where the inner and outer skins are spot welded together. They are folded in from the factory so i had to prise them them back so i could get behind them to remove the underseal.
Here you can see the standard arch, and lip, and that silly flat face on the arch, which actually isn't even vertical, it points inwards. There's a lot of space to be gained by stretching this out to follow the rest of the arch.
There is also this big chunky bit at the top of the bumper. I found it impossible to flare the outer arch without cutting a slit in this as you'll see later.
Here is the arch roller starting to do it's work.
View on the inside. See how the lip tucks right in. It won't do this unless you remove all the underseal from behind it. Any lumps you leave will show up on the outside.
The tabs folded back in. I couldn't get the roller in at the lower front edge of the arch and had to beat all that by hand (well, with a hammer)
Really starting to take shape now. Combination of hammering and rolling to get it this far, about 3 hours work.
lip nice and flat on the inside. Give it a good coat of zinc primer.
and the tabs again. note how between the tabs you can actually see a gap and see inside the car! hence the need for seam sealer.
And the outside
Compare to the standard arch
18"s now fit no problem
acres of room to go even wider
Note the hole at the back where i had to cut it. This now needs welding up
Once all that is done a coat of seam sealer down the inside and then it can go to the bodyshop to finish off the outside and apply paint.
Modified by phatvr6 at 10:23 PM 2-10-2008