Protecting Undercarriage Fasteners

[ninjanick]

I plan to use Rubberized undercoating for the entire underside of the vehicle and it got me thinking about the hardware that will poke out below the undercarriage to secure my battery boxes. I would like to be able to remove the boxes if need be so I'm worried that a screw shank and nut protruding down may cause clearance issues. I plan to set ride height around 5". Is there a solution to prevent the hardware from damage? Worst thing is to scrap against a speed bumper and damage the hardware not allowing easy removal. Or just weld the nut in place and paint over it?

[Hindsight]

Most people are using the very flat hex head cap screws that FFR provides with the kit (the 1/4" ones). They are VERY flat and a little rounded and you can get extras from McMaster. At 5", I wouldn't worry much about those getting damaged.

[UnhipPopano]

Ok, I can see being concerned about scraping the undercarriage in the front, middle, and end of the car on big speed bumps. The battery box is so close to the front wheels, I am not visualizing a speed bump that would do this. On the other hand, I have driven on some bad roads that the crest stuck up quite a bit and might do that type of damage. At the same time I could see it take out the oil pan.

[billjr212]

I made it so the bottom side is always the button head side of bolts (had to swap things out in a few cases) so any excess bolt length and the nut is on top. Figured this minimizes the amount hanging down and a minor scrape or hit shouldn't affect the hex inside the button head. Just my theory anyway.

[ninjanick]

To keep the batteries flat against the bottom surface of the box, I'm countersinking the thru holes inside the box so the nut will be on the bottom. I'm mainly worried about the battery boxes behind the seats. I think that area is the most vulnerable. Sounds like I might be worried about nothing. I guess worst case I have to cut the screw/nut out.

[longislandwrx]

what did you guys do for the seat bracket bolts? grade 8 button head bolts?

[ninjanick]

what did you guys do for the seat bracket bolts? grade 8 button head bolts?

I didn't use the seat brackets since I have NRG seats installed so I had to weld in supports/rails. I'm short so I welded them on top of the frame tubing which allowed me to weld in bolts from the bottom. All this fits within the space between the frame and the bottom aluminum piece.

[longislandwrx]

yeah my Sparco seat rails bolt in... I could tack them but that limits me in the future. just don't want them to get sheared off.