Getting ready to paint, I noticed horizontal cracks running across the windshield posts of my 72 Mach1. Very thin, I thought they were paint scratches at first but when I sanded the paint off, they were still there.

About 2 inches down from the top of the windshield, they are associated with areas where there is body lead applied to the post. One is cracked right at the edge of the leaded area and the other crack goes through the leaded area. Is this common?

I have yet to remove the interior trim pieces, the glass, and the drip rails.

I don't know if this has any bearing on it, but it appears that the roof skin might have been replaced. On the passenger side, there is a weld that runs from the back of the rear window, along2-4 inches down from the edge of the roof and then turns toward the center of the car and terminates about half way along the right side trunk opening. The "weld" if you can call it that consists of a series of tack welds about 1 1/4" inches apart. It had been buried in 1/4-3/8" bondo which had cracked heavily horizontally and vertically.

The driver's side, where the roof joins the side, is deeply buried in body lead which had bulged up in lumps about 1/16" tall. I haven't dug into that yet because I haven't learned lead work.

 

you dont have to lead the surface back....just get all of that out of there and see what you got...make sure to wear a good mask also no facial hair you dont want leaks etc....

you can fix anything under there then wipe with metal to metal(its an alum based filler and is more corrosion resistant than lead....)