Q&A: September 26, 2019 Edition

Q. Does anyone make a replacement convertible top with a “moonroof” (meaning a clear plastic piece over the front)? I recall seeing one in the old Warshawsky/J.C. Whitney catalog some time ago.
— Brian Cheske, Villa Park, Ill.

A. Golly, I don’t know. The J.C. Whitney of today is a far cry from the outfit that used to send me a new catalog (it seemed like) every week. I see there are convertible tops on its website, but none like the type you seek. You don’t say what car you want it for, but I suspect your best bet is to find a good auto trim/top shop somewhere near you and have one made.

Q. I just saw your answer to the Q&A question about GM headliners (Aug. 15). Having replaced more of these than I care to remember, I thought I would give you my information.

GM’s 1977 “B” bodies and subsequent models started using a headliner that did not require cross bows. It used a cloth material, velour or felt that had a foam rubber backing. This was then glued to a molded hard styrofoam backing. It’s not the adhesive that fails, but the foam rubber material on the back of the fabric. Because of the ridged styrofoam backing, it would hold in place using only the perimeter moldings and the interior lamp. This was a much cheaper way to do it, but with heat and age, the foam rubber turns to powder and the fabric falls down.

Now, as to total replacement, when available I used material sourced from GM parts. Later, I used SMS Auto Fabrics in Canby, Ore., and got the exact same thing. The perimeter moldings are not easy to remove as the plastic retaining clips are mean. They are “V” shaped and need to be drawn together right to left. I have a very old pair of 90-degree thin flat snap ring pliers that I use on them. They are also designed to draw the molding in to depress the headliner and that makes them fit tighter. Some will break on removal so it’s nice to have new ones on hand. Also, the visor supports will smash the styrofoam backing into the body causing it to stick. You will need a thin scraper to release it otherwise you will rip the corners out. Be very careful with the backing as it will be as brittle as a potato chip. Believe it or not, the old adhesive and what’s left of the foam can be removed with a very soft wire brush attached to an electric drill. A can of aerosol trim adhesive and new material, trim around the edges and time to reinstall. I have seen auto trimmers leave both the front and rear molding in place and slip the headliner in and out. I am not that good and have never tried that.
— Phil Aubrey, Merlin, Ore.

Q. In regards to Eric Anderson’s concerns about 1980s GM headliners bubbling and falling down (Aug. 15), I have the following reason for this. When GM starting using the foam blanket above the headliner they used adhesive on the foam, which absorbed the adhesive thus allowing limited sticking of the headliner material. This became even worse if the line crew put the adhesive on and went on break: the adhesive would partially dry while they were out, and caused this problem. The other issue is that when outside temperatures got very warm, this would also loosen the headliner and cold weather would do the same thing. I have had several GM vehicles on which this has happened.

I have a friend who worked for GM styling division for his whole career and GM was well aware of this problem as the adhesive was substandard. I found a way to mostly fix this issue by dropping one side of the headliner and spraying new adhesive on the foam, as well as a light coat on the headliner material. I had a helper in tucking the headliner back. Through another friend who has an upholstery shop, I found that 3M has an excellent adhesive. Hope this tidbit helps.
— Scott G. Peterson, Duluth, Minn.

A. Welcome to GM headliner week at Old Cars. Thanks to both of you for sharing your experiences. You’ve pretty well ruled out my suggestion for injecting new adhesive behind the headliner material. I yield to your expertise.