Ronal (15" from a 5k) Center Cap:

[Tony Hoffman]

Which is called Butyl. You can buy it in a roll at FLAPS.

Tony

On Fri, Mar 20, 2009 at 11:07 AM, urq <urq at pacbell.net> wrote:
> ... when they were new the caps should have held themselves in ... I suspect
> the goop may have been installed by a PO or service provider somewhere along
> the way.
>
> You need to find some adhesive that won't set as the caps need to come off
> when you have tires fitted ...
>
> The stuff that comes to my mind is that sticky gasketing material they use
> to hold and seal taillights ...

Steve is right on with the caps. They hold themselves in place. I'm
assuming you are talking about the 20 (or so) spoke ronals from an
early 5000 Turbo, 80 or 81? I had them on the V8 for winter wheels at
one point in time.

The taillight stuff is called Butyl. You can buy it in a roll at FLAPS.

Tony