Ask most any car builder, restoration or otherwise, what the most difficult aspect of dealing with classic car and the answer is always the same, wiring. Chasing down shorts and open circuits has certainly caused more than one enthusiast to call it quits with a project. The problem is, the older a car gets, the worse the wiring situation becomes, especially when dealing with 50’s and older cars built with cloth-covered wires.
The biggest difficulty with cloth-covered wires is the cloth itself. As the material ages, it gradually becomes more and more brittle, which eventually leads to entire sections falling off. Not only does this not look good, it is an extreme fire hazard. It takes very little spark to set a car on fire, and the results are devastating.
Once the integrity of the wiring is broken, the actually wire begins to deteriorate to the point that corrosion and fatigue breaks the wire, causing an open circuit, or worse and intermittent open that always springs up at the worst possible moment.
While the typical solution is repairing the original wiring or replacing it with a modern vinyl-covered kit, these options just leave the car looking hacked up or modernized, which detracts from the original look of the car. The best solution for a 100-percent restoration is a complete original-style wiring harness.
These kits like the one we used here from Douglas B. Seybold, are built to the original factory specs, loomed in cloth, in the correct positions, lengths and locations, greatly simplify the installation. The best part about the kit we used (and most of the other kits that are on the market) is the wire used to build it is a vinyl-covered wire that is covered in correct-coded cloth. That means you get the best of both worlds, with a correct, 100-percent original quality wire that looks the part with added durability and safety of modern wiring. Even though these kits cost more than a retrofit wiring kit, for a true restoration, this is the only real solution. Kits can be found for just about any classic, considering we found a kit for a 1941 Buick, you should be able to find one for your classic.
As with any project, this one requires a certain amount of skill. Even though the kit comes pre-terminated (the fitting s are already attached to the wires) for most applications, there are a few specialized connections that require some electrical knowledge. The turn-signal wiring for our 41 Buick required the reuse of the original bulb housing and the small round wafer board. The original wires were cut and removed, and the new wires slid in the holes, the new contacts were the crimped on and the restored assembly was reinstalled. You will need some specialized tools to complete the installation correctly. A set of high-quality crimpers (those combination crimper-cutter-strippers from Radio Shack are not high quality) from Klein (available at most hardware stores) are the best way to go for this project. Additionally, a quality set of wire strippers makes it easier to cut through both the cloth and the vinyl, leaving minimal cloth strays, which need to be removed.
When starting a project like this, make sure you can have the vehicle down for a while. Even though the wiring project can be completed in a weekend, the level of disassembly alone can take a day or two. Unless you are an experienced automotive electrician, do not just go through the car hacking everything out and hoping you will remember it all later, attack each section at a time, removing the old wiring, installing the new section, removing the next section, etc. This not only keeps things fresh in your mind, but it simplifies the task in sections, which is a good idea as a lot of builders absolutely dread wiring and looking at a car without a stitch of wiring is panic-provoking.
While the switches, circuit boards, and contact boxes are free of wiring, it is also a good idea to take a brass brush and clean the contacts. The environment under the hood of a car is not the best for wiring, water and fuel attack copper contacts, reducing their ability to conduct, which causes even more problems. If you find a really corroded and tarnished contact, a little baking soda\water paste will do wonders to clean up old contacts.
To show a few of these tricks, we re-wired a 1941 Buick Eight using a Douglas Seybold restoration wiring kit. Along the way, we removed the dash for restoration and found a well-hidden rat nest. All in a days work.