Last update: Jul 23 2016
Subaru uses Japanese Industrial Standard (JIS) size flange bolts throughout their cars. Most bolts in the car are M6, M8, or M10. The JIS head sizes and pitch differ from the more common DIN standard sizes. Your local hardware store likely stocks the DIN sizes only.
|Diameter||DIN Head Width||JIS Head Width||DIN Std Pitch||JIS Pitch|
A JIS flange bolt kit is a good investment to keep the hardware in the car consistent, minimizing wrench swaps. A good source for individual metric fasteners is BelMetric.
Rivet nuts are a simple way to install threads to sheet metal or fiberglass panel. They have a clean high-quality appearance when installed, and look almost like the OEM installed them. Rivet nuts are particularly helpful for blind installations where you want to bolt something securely to a panel or frame rail and do not have access to the back side. The tool is a little tricky to figure out the first time. I recommend installing a rivet nut of each size into a scrap for practise and to use as a reference so you can see exactly how deep the threads end up. This makes it easy to select the right length screw. Thread sizes larger than M6 or 1/4in require the larger lever-handle tool, which can be awkward in tight spaces.
All bolts securing high current electrical connections should have Nord-Lock wedge lock washers installed to prevent repeated heating and cooling from loosening the bolts.
I prefer using aluminum rather than steel wherever possible in an EV conversion due to its light weight and machinability. One problem with aluminum is that if you paint it as you would steel, the paint usually rubs right off. I found the procedure below works very well to get paint to adhere to aluminum.
12.0 VDC With Maximum %2 Voltage Drop
When you need to fasten two pieces of aluminum and either space is too tight for a conventional fastener or you want a seamless cosmetic appearance, you can easily make your own flush rivet. Drill a hole 1/8in diameter through the materials where you want to join them. Chamfer the outside edges of the holes. Cut 1/8in diameter aluminum rod from the hardware store to a length 25% longer than the total thickness. While holding the two pieces together tightly on an anvil, hammer the rod until it is flush. The rod expands to fill the hole, flowing into the chamfers. After a little filing and sanding, the rivet is invisible.
An automotive electrical connector kit is a must-have item when converting a car to electric drive. Two popular connector systems are the Delphi Weather Pack and Metri-Pack. The best source I found for connector kits is MJM National on eBay.
Delphi Weather Pack connectors are widely available, inexpensive, accommodate a large range of wire sizes, 22-12 AWG, and carry up to 20A. The best Weather Pack kits are at DIYAutoTune.
Delphi Metri-Pack 150 connectors are slightly more compact and modern than the Weather Pack. They accommodate wire sizes 18-16, and carry up to 14A. Both sealed and unsealed versions are available, although the unsealed are difficult to find. The JEGS Unsealed Connector Kit has 1-4 and 8 pin connectors. The 6 pin connectors are available at Mouser, part numbers 15396848 and 15396849.