I bought a 91 Burb about 4 or 5 years ago. I checked high and low for rust and it was clean. Now I've got the usualy Burb rust at the roof lines. At the tops of the rear glass, at the roof joints in the door jambs and really bad at the holes around the roof rack. I know this is pretty common to all Burbsm but, I need to make a decision. I could fix it, but, what will prevent it from happening again or in different areas? Is there a seal issue with the roofs in Burbs? Anything I can do to prevent further rust from happening? I have 5 other GM trucks, all 73 to 87 / 91. all older than the Burb, and all less rust! The trucks do sit out in San Francisco. Is there hope, or should i just consider purchasing a Burb .... or something else just as big. Do the later generation Burbs rust like the 73 to 91 Burbs? Thanks, Eric M.