Jim Smart
December 26, 2015

This is the third installment of our Restoration Mistakes series, dealing with common mistakes made when building or restoring a classic Mustang and how to avoid them. As we said at the beginning of this series, “We’ve been horsing around with classic Mustangs for more than four decades and have come to the following conclusion: we’ve never stopped learning from our mistakes nor have we stopped making them. When you’re restoring a classic Mustang or building a hot restomod it is important to see the pitfalls before you find them, not after stumbling and falling into them. Silly stupid mistakes we make time and time again. Whatever your reason for screwing up, we’re here to remind you we have been there ourselves and know how not to make the same mistakes again.” Our third tech tip deals with body panel fitment.

Body Panel Fitment Flops

This is a hot button issue for any restorer. It seems we always remember body panel fitment in the wake of bodywork and paint instead of beforehand. Body panel adjustment with a painted body is just asking for paint damage—ask us how we know. Body panel fitment and adjustment must be performed prior to paint. Adjustment should always begin at the B-pillars with door adjustment, then forward to front fenders, hood, fascia, and bumper.

If you are replacing rear quarter panels, the doors and deck lid must be already installed and adjusted prior to quarter panel removal and installation. These are important reference points to work with. If you install quarter panels cold without door and deck lid reference points you risk a nightmare scenario when it’s time to fit the doors and deck lid. Few things could be worse than discovering that the doors and deck lid don’t fit once the quarter panels have been welded and permanently installed.

Another area we don’t pay enough attention to replacing quarter panels is quarter-to-window clearances. This is a good example of insufficient quarter panel to window gap. Weatherstripping will tend to hang up whenever the window is rolled up or down.

What’s more, the quarter panel’s relationship to the rear quarter window must be established during quarter panel installation, not afterward. If the quarter window gap between window and quarter panel is insufficient you will run into weatherstrip clearance issues you don’t want to discover once the quarter panel is already welded in place. The deck lid must also be installed and properly adjusted prior to quarter panel installation.

And stop slamming the door!