How To Align A Fender

You don’t need any fancy equipment for basic fender alignment—just a good eye and lots of detail-oriented patience. Make sure that you have a variety of thick and thin shims on hand to dial in gaps. If your fender bolts are crusty or missing, resist using cheesy looking hardware store bolts. Instead, order a front-end fastener kit from a resto supplier. Most include factory-style washer bolts, an assortment of shims, and some of the weirder J-clips that hold everything together.

On this Chevelle and similar GM A-body cars, five bolts secure the rear of each fender to the body shell. Shims can be placed between the fender and body at each of these locations. Shimming at location A will push the top of the fender outward horizontally. Adding shims at location B will raise the fender upward, and make the side profile (the fender’s bulge) flatter. Similarly, shimming the two lower locations (D) lowers the fender’s bottom edge and flattens the bulge. Playing with shims at location C changes the width of the fender-door gap, making it thinner (less shims) or wider (more shims). Now’s a good time to make sure each door is aligned to the rear quarter-panel before you proceed.

With all four wheels on the ground, Cross snugged every bolt (except at location C) to check the fender’s overall fit. If your fender is seriously out of whack, you’ll see it now. This fender fit pretty well on the first try, but the uneven body line transition between the fender and door meant we had some shimming work ahead of us.

First dial in the height of the fender peak to match the height of the door. Cross adjusted the top of the fender to fit flush with the door by shimming location B; 0.100 inch of shims provided the proper height.

The top of the fender sat too far inward relative to the door, which meant we needed some shimming at location A. The bolt is accessible with a 9/16-inch box-end wrench with the door open. Cross added 1/8 inch of shims, tightened the bolt, and closed the door to check fitment—perfect. Just don’t close the door until the bolt is threaded in, as the bolt head may dent the door when it’s close.

With the top of the fender in check, Cross moved on to correct the side profile of the fender, which was bulging out slightly beyond the profile of the door. After loosening the two bolts at the bottom of the fender (location D), 3/16 inch of shims at each bolt location reduced the fender’s bulge to match the door’s profile.

The fun begins! Shimming one area to perfection often sends another adjustment out of whack. In this case, shimming the fender bottom (location D) pulled the top of the fender a little too far inward. No problem—Cross loosened bolts A and B, carefully moved the fender outward, and inserted another 1/16-inch shim at location A. That’s all it needed.

Cross then proceeded to check the fender-to-door gap. Toward the top of the panels, the gap looked satisfactory, so he shimmed bolt C to take up the gap and snugged it down. However, there wasn’t enough separation between the lower halves of the panels. Time for one of the tools of the trade—he used a body wedge to carefully widen the gap and tightened the rear bolt at location D when he was happy with the spacing.

A crucial step is making sure the lower portion of the fender is aligned with the rocker panel. The rear has already been aligned flush with the rocker, but the front (behind the wheel) is bowed inward. Cross gently tugged out on the front corner and tightened the front bolt at location D when he was happy with the straightness.

If the fenders you’re using aren’t original to your car, this might be a familiar sight. Although everything else lines up, there’s a gap at the rocker panel. Most body shops would call this good—but not on a high-caliber job from the Hot Rod Haus. For Cross, this means carefully measuring the gap, pulling the fender back off the car (first taking note of the shims used), and welding additional metal on the rocker panel to tighten the gap. That’s something we’d certainly leave to the pros, and it reinforces the importance of pre-fitting panels before final bodywork and painting.

Here’s another reason why you should always pre-fit panels: The door profile on this Chevelle had a few high spots that kept it from lining up perfectly with the fender. Cross used a body spoon and a couple of well-placed hits with a body hammer to bring the door into shape. Virtually no additional filler was required.

The upper body crease is a prominent feature on ’70-’72 Chevelles. Translated, this means a misaligned crease looks really crappy, especially after fresh paint. We couldn’t figure out why the body line didn’t line up on this perfectly installed fender, but Cross suspected that block-sanding the door and fender together would line everything up.

Sanding through a thin guide coat revealed the laser-straight body line. A half-hour of Cross’s work (we’d probably have spent an hour or two at it) not including time spent extending the rocker panel resulted in a perfect-fitting fender. And even though the fenders will be painted off the car, we’re guaranteed that reassembly will be a slam dunk.

Any good bodyman will tell you that surface prep is at least as important as the paint itself. Cheap paint over crisp, straight body lines always looks better than nice paint over waves. Similarly, poor panel fit after the fact can ruin even the straightest panels and the nicest paint job.

Perfecting the gaps can be a tedious process, but that’s what separates a stunning restoration from a mere paint job. The good news? The basic procedure won’t cost you any more than a few bucks for shim packs. The not-so-good news? You may find that some panels require significant working time, aligning effort, or serious metalwork (i.e., cutting and welding) to look “right.” But chances are, if your car hasn’t been seriously tweaked in the past, this step-by-step approach to aligning fenders will yield panel gaps so straight they’ll look laser-cut.

We followed along as Hot Rod Haus owner Dave Cross worked his magic on a ’70 Chevelle front clip. Keep in mind that this car is still in bodywork stages, and ideally, that’s where yours should be when you’re aligning its body panels. Fitting the panels before painting allows you to play with shims and work the metal into shape if necessary without worrying about damaging the new paint.

When everything fits the way it should, you tear it apart, paint it, and put it back together. Keeping track of the shims used at each location will make post-paint assembly a snap. Remember, fitting panels after they’re painted will invariably lead to chipped edges, mediocre fit, and loss of sanity, so save yourself some grief and pre-assemble that body using Cross’s foolproof method.