Starting this thread to help myself and others who may find themselves in the same situation.
I took my Targa on the local PCA Holiday charity drive last weekend and while enjoying Christmas music along the route I noticed a clunk or rattle coming from the rear parcel shelf area. I thought something had come loose around one of the rear Blaupunkt speakers that were installed in the car by a previous owner.
I pulled off the speaker grill and much to my surprise it was the speaker itself that was rattling. It seems the flexible material that connects the speaker cones to the speaker enclosure had rotted away over the years and the speakers had started to rattle, hiss, and pop during the Holiday drive.
I removed the speaker enclosures to see what sort of holes had been cut in the rear trim panel. Luckily the holes themselves are only about 4 inches in diameter with the screw holes spaced about 4 1/2 inches apart.
I decided to remove the rear trim panel expecting the worst but surprisingly the backside was clean and looked almost like new and the sound deadening material beneath also looked very good minus the areas that had been "excavated' to install the speakers. Luckily they had not cut any metal during the install but sadly they did run some sheet metal screws into the rear shelf metal.
I also looked all around the base of the rear glass and did not find any signs of rust, just shiny Albert Blue plaint all around. I did find one area where the rear glass seal was puckered. Otherwise it was surprisingly clean.
Any ideas how I can fix the warpage in the top center of the rear trim panel while I have it out? Heat/steam perhaps? If I can get it straight I could always apply a bit of fiberglass to the backside for strength and to help stop it from warping again.
I will also need to figure out a solution for speakers that fit the holes and depth without causing any new damage. I could possibly replace the speakers in the old Blaupunkt enclosures to maintain a somewhat vintage look but I am guessing there are better alternatives. On my Targa the biggest issue is the depth of the speakers. Even with some of the sound deadening removed under the stream panel there is still only about 1 1/8 inch of depth, the rest is above the surface of the rear trim panel inside the 1 in tall speaker housing.
Show your rear shelf speakers solutions!