S3 Crash Pad Installation
Posted: Wed Feb 18, 2015 9:06 pmThe dash crash pad in my 1967 S3 SE Coupe was in bad shape; lumpy, out of position, cracked, and ugly, the result of a previous owner's removal and replacement for reasons unknown to me. The dash was previously replaced using about 3-4 lbs. of silicone glue in what looked like an attempt to level it to the fiberglass cowl. As a result, it was positioned too high at the dashboard. I also replaced the cracked and delaminating dashboard.
I obtained a new crash pad, then tried to find any information on preparation and installation details, but found very little that really explained the process in any detail. I know that restorers are faced with crash pad replacement from time to time, so it can't be that no one knows how to do it properly, and I suspect the professionals just don't want to give away their little tricks and secrets.
My new replacement crash pad was an empty shell, with no foam inside. One detail that I gleaned from posts on this forum, was that expanding foam can cause warping and deforming of the crash pad, because ABS, particularly in the case of the thin crash pad, is very sensitive to high temperatures, which can occur with expanding foam.
To counteract that potential, I applied strips of window installation flashing tape, the stuff used to install new windows into buildings, to the underside of the crash pad. This material is a thin, rubber like material with a very strong adhesive backing. I figured the thin rubber would provide not only some degree of thermal protection to the ABS from the expanding foam, but to hopefully provide additional thickness to the crash pad for resistance to future cracking.
I selected a fireblock expanding foam for its claimed greater resistance to high temperatures, and reasonable expansion ratio - less rather than more - to reduce exothermic buildup. I then used clear package tape to mask off the front lip of the crash pad and the dash vent grill opening where I did not want the expanding foam to adhere, since it can be very difficult to remove, either when wet or cured. I applied the foam, and when cured, shaved it with a variety of tools, including a hack saw blade, and random orbital sander. It took a few tries to get the amount of foam correct for a good fit to the fiberglass cowl. I used the old dash board as a fitting/drilling guide for the dashboard screws, and then used more expanding foam to install the crash pad to the fiberglass cowl. After minimal trimming of the excess foam at the grill opening, I brushed on black paint over the foam so it wouldn't show through the grill.
All of this was done with the windscreen in place, and I have not found a need to remove it for this project. I have yet to finish the entire project, and need to screw the top vent grill down to the pad, and complete some extensive re-wiring, then install all of the cables, etc. The new dashboard is fully assembled, and pre-checked for fit.
I neglected to take pictures at each step, so hopefully the description will help bridge the gaps. If I think of any other details, I'll update this post.
Cheers,
Greg Tatarian
I obtained a new crash pad, then tried to find any information on preparation and installation details, but found very little that really explained the process in any detail. I know that restorers are faced with crash pad replacement from time to time, so it can't be that no one knows how to do it properly, and I suspect the professionals just don't want to give away their little tricks and secrets.
My new replacement crash pad was an empty shell, with no foam inside. One detail that I gleaned from posts on this forum, was that expanding foam can cause warping and deforming of the crash pad, because ABS, particularly in the case of the thin crash pad, is very sensitive to high temperatures, which can occur with expanding foam.
To counteract that potential, I applied strips of window installation flashing tape, the stuff used to install new windows into buildings, to the underside of the crash pad. This material is a thin, rubber like material with a very strong adhesive backing. I figured the thin rubber would provide not only some degree of thermal protection to the ABS from the expanding foam, but to hopefully provide additional thickness to the crash pad for resistance to future cracking.
I selected a fireblock expanding foam for its claimed greater resistance to high temperatures, and reasonable expansion ratio - less rather than more - to reduce exothermic buildup. I then used clear package tape to mask off the front lip of the crash pad and the dash vent grill opening where I did not want the expanding foam to adhere, since it can be very difficult to remove, either when wet or cured. I applied the foam, and when cured, shaved it with a variety of tools, including a hack saw blade, and random orbital sander. It took a few tries to get the amount of foam correct for a good fit to the fiberglass cowl. I used the old dash board as a fitting/drilling guide for the dashboard screws, and then used more expanding foam to install the crash pad to the fiberglass cowl. After minimal trimming of the excess foam at the grill opening, I brushed on black paint over the foam so it wouldn't show through the grill.
All of this was done with the windscreen in place, and I have not found a need to remove it for this project. I have yet to finish the entire project, and need to screw the top vent grill down to the pad, and complete some extensive re-wiring, then install all of the cables, etc. The new dashboard is fully assembled, and pre-checked for fit.
I neglected to take pictures at each step, so hopefully the description will help bridge the gaps. If I think of any other details, I'll update this post.
Cheers,
Greg Tatarian