Crack Between Rear Pillar and Roof

Just thought I'd throw my two cents into the mix. The crack you see is indeed the the lead filler used by the factory to cover the joint where the roof skin meets the quarter skin. It can crack for a number of reasons,(this applies to all cars not just Z's).

The most probable in my opinion is simply age. Lead, although it has great flexibility can crack just like any other type of filler. In fact lead is the hardest type of filler toget to stick properly although once it is stuck it generally stays put.

DO NOT simply resolder the lead with a solder gun as this will only last for a short while and the crack will reappear. I'm a bodyguy and have encountered this problem before especially on 87-93 Mustangs. Here is what I do and have never had a single comeback.

First remove all of the old lead on the seam. A oxy-acetlylene torch would be the best way. Set the flame to neutral,(use a weld tip not a cutting tip) and slowly and gradually heat the lead. Use a wire brush while you're heating and brush the surface until the lead starts to come off. Continue haeting and brushing until you have removed all that you can. Examine the seam for any signs of weld stress and repair if neccesary. Drilling some5/16 holes through one layer of metal and plug welding the holes with a MIG is a good precaution. But make sure ALL the lead is gone from the seam. Then use a good quality fiberglass filled filler and fill the seam. Follow up with a skim coat of poly filler and the repair will last for a long time. Hope this helps!:classic: