One of the marks of a quality restoration or custom build is the presence of perfect panel gaps. And as anyone who has ever rebuilt a vehicle knows, this can be tricky business. It starts with a “square” and proper body to hang your doors, hood, and trunk lids from. Assuming that’s all good, there are also a lot of fine adjustments required during reassembly to get things right.
Over the years, numerous tools have been developed to help professionals and DIYers alike with their panel gaps. Here are three that we’ve found helpful at different phases of the project. These also work well for adjusting body panels that may have had previous work performed.
Pin Alignment System
Aligning your panels before final finishing and reassembly is a smart move. And once you get everything set during pre-assembly, the best way to capture those settings is to index them. This pin alignment system is designed let you drill reference holes in door, hood, or trunk lid hinges using the included bits.
Once you drill these pilot holes, you can perform your refinishing and paint work on jambs. When it comes time to hang all those panels back on the car, just insert the magnetic alignment pins in the predrilled holes. Your hinge will be right where you set it, letting you bolt everything back together without movement.
You can protect the open alignment holes with a layer of paint to prevent rust from forming. If original appearance is a concern, you can also fill or spot glaze the holes and blend with touch-up paint.
Pro tip: If you’re setting the alignment on an empty door, don’t forget to add weight before drilling. You’ll need to account for the weight of missing glass, door handles, mirrors, window regulators, speakers and any other trim. Failing to do so will probably result in doors that sag and may not latch properly.
Hands-Free Panel Gap Setting Tool
Sometimes setting gaps requires adjusting fenders, cowls, or other panels in relation to other fixed panels. For instance, getting an even gap from side to side on front fenders once the hood is mechanically aligned. This panel gap setting tool lets you do that without any helping hands. It uses a series of flat, fixed-width finger gauges attached to a suction cup-mounted arm.
Each of its non-marking plastic blades is 0.045 inches, or about 17 gauge, thick. You can either set the gap to a pre-determined dimension or equalize the overall gap by make adjustments in either direction. A gap the width of three blades would be just over 1/8 of an inch at 0.135 inces, pretty typical for a modern vehicle. A factory-correct gap on an older car might equal four or five blades.
This set comes with three individual gap-setting tools. This allows you to set consistent gaps along one edge of a panel like a hood, for instance. Or you can triangulate and set equal gaps at once across three different openings. Either way, this set can be helpful in setting your spacing before or after paint without fear of damage.
Big Kid Panel Setting Blocks
When you’re building something special and want tight gaps no matter how much work is required, these are your tools. The steel panel setting blocks from Big Kid Blocks is perfect for the fabrication and pre-finishing phase of a project. The tool is machined to a precise dimension that will provide perfect show car-appropriate gaps. Simply build your panels using the gauge as your guide when testing fit.
Too big a gap and you might choose to add material with welding rod or body filler. To narrow a gap, and you can turn the gauge around and use the outside marking edge to transfer the proper gap dimensions to the panel that can best be trimmed. The backside of the tool is also flat for confirming flush surfaces across panels.
After paint and during reassembly, a plastic Final Assembly Gauge from Big Kid Blocks lets you make fine adjustments without damaging the paint. In this way, it’s like the gap setting tool above. However, it’s designed to help you reassemble based on the pre-set dimensions of the company’s steel block.
However you decide to set your panel gaps, take your time and get them right. Most shops will tell you this is one of the most nerve-wracking parts of a rebuild. The tools above were all developed to help get great results and prevent damage.