Hands On Cars Ep. 4 – Replacing a Rusty Roof


In this episode Kevin is all about undoing the errors of some previous owner of the Zed Sled Camaro Z28. He finishes up with the rust replacement on the bottom of the car, and tackles the cause of all the rot in the first place: A leaking aftermarket sunroof installation.

With the use of a compete replacement roof panel from National Parts Depot, a MIG 175 welder from Eastwood, and lots of sweat equity he undoes years of rust, dents and neglect. The original factory panel is unleaded with the help of a propane torch, then using Eastwood double sided spot weld cutters the original fatigued, bent and sunroof scared panel is taken off. A large section of the original outer panel is cut and welded into a patch for where the sun roof was in the inner panel. Finally the new panel is spot welded onto the old roof, and then the door edge folded around with a body hammer and dolly set.

Also, Kevin meets Jerry Dixey from Street Rodder Magazine at the Eastwood Summer Classic car show. Together they go cruising in a custom 1959 Chevy Impala with a killer Roadster Shop independent suspension chassis put together by Hot Rods by Dean. Besides the modern injected LS 427 625 horsepower motor, and 4L80 transmission, it looks fast standing still with its stellar Ferrari Red paint.

Write Up & How To

In this episode of Hands on Cars Kevin removes and replaces the wavy, rust old roof with its scar from a sunroof in the 1978 Chevy Camaro Z28 Zed Sled project car. Plus he shows us the finished floor replacement from last episode. The rusty floor damage is very typical of an old car with a sunroof, especially a universal aftermarket unit. Luckily the rust didn’t get into any structural areas, but there was an awful lot of it.

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1. A new roof panel for GM F-body cars (Camaro and Firebird) of this generation is available from National Parts Depot, so the first thing to do is remove the old panel.

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2. Sanding off the old paint in the area where the roof joins the B pillar reveals not only the original factory joint, filled with old school lead solder filler, but 2 areas that had been repaired previously. Because lead can be toxic, you should never sand old lead filler.

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3. The proper safe way to remove old lead filler is to melt it out with a standard propane blow torch. It actually comes out really easily this way.

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4. Now that the lead and filler is gone you should be able to see the original factory spot welds. Mark these to drill out later.

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5. To make the job easier, use the Eastwood electric metal shears to cut off as much of the old roof panel as possible. Doing this allows you better access to the space between the inner and outer roof and makes it easier to remove the panel.

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6. Now, using the Eastwood 3/8 inch, double-sided spot weld cutter, start drilling out the old factory welds. Careful you don’t use to high a rate of speed on the drill, or you will just burn up the bit and not cut through the metal. To make your life easier you may want to dimple the center of each weld first with a smaller drill bit, like a 1/8 inch.

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7. On this particular model of car, the area of the roof above the door isn’t welded at all. The metal is just folded around the inner roof panel, much like a door skin.

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8. Once most of the roof is gone, Kevin discovers even more rust and rot on the passenger side. Unlucky for him no one makes replacement panels for this area, so this will need to either be repaired with a junkyard piece (like the passenger door latch panel was) or custom fabricated. Luckily this area will be hidden under the headliner and will never be seen.

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9. Test fit the new panel, now that most of the old one has been removed. The final place to be trimmed for fit is the A pillar. This is a much more complex shape than it seems, with channels for both the windshield and the door glass that need to be matched up.

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10. Before you can weld the new roof panel in place however, you need to patch the inner roof where the old sunroof hole had been cut. No one is going to see this area once the headliner is in. But since the roof on a uni-body car is structural, and this is a pro touring project that will see some serious Gs, it needs all the structure it can get.There is plenty of good metal in the old roof panel that was rut off, and it matches the slight curve of the roof. Flip it around so the solid part covers the hole and clamp it to the inner panel.

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11. Trace the shape of the hole on the underside of the roof.

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12. Trace and cut so that your patch panel is at least an inch, if not bigger, all the way around the hole. This way you can just overlap weld it to the good existing metal, instead of trying to fill the hole. Remember, no one will see this repair, so the most important thing is that it is structural, not pretty.

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13. Clean the areas around the hole of any rust and dirt with a wire wheel and prepare them for welding.

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14. Spray the area with Eastwood Fast Etch to quickly dissolve any rust you missed, and clean out the rust in the pits.

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15. Scrub it with a scuff pad to really work it into the pits.

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16. Wipe down the area next with the Eastwood Pre Painting prep.

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17. Then spray all the places that will be welded on with Eastwood’s Weld Through Primer.

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18. Finally, while you have access to this area, spray the rest of the inner roof with Eastwood’s Rust Encapsulater.

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19. Now you can weld the patch panel to the inner roof.

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20. Finish it off by spraying the welds with more Rust Encapsulater, the rest of the patch will be fine with the baked on factory paint from 1978. On the inside apply seam sealer to help keep out moisture.

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21. A 3/8 inch pneumatic hole punch will make short work of putting holes around the perimeter for rosette welding. If you don’t have a punch you can use a drill and bit, but it will just take a lot longer.

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22. Squirt some flexible foam between the inner and outer panel, to help keep them from rattling together and “oil canning” at speed.

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23. Then just start welding in your holes, replicating where the factory spot welds were.

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24. The A pillar area may require a little bit of tweaking to get all the surfaces to line up.

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25. Once it all matches, weld it in place.

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26. The final step is fold under the seam over the door. A simple body hammer and dolly are all you need, and lots of beating.

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And that’s it, no more rust or leaky aftermarket sunroof. Before primer and paint you will need to grind some welds and apply some body filler, but that is a project for another episode.

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One Comment

  1. So it doesn’t really state how you finish the seams, did you replace the lead on the sail panel joint or did you use a different technique?

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