Exterior

Undertray Fastener Replacement

My car had a full dealer service history when I bought it. In fact, I had the seller's dealer in Denver do the timing belt/water pump/rollers & tensioners before I even saw it. So when I got it home I was less than thrilled with the assortment of fasteners they had used to hold the tray up. The screws for the front were gone, so it was hanging from the two steel brackets. At the rear, only the two 6mm bolts into the steering rack were in place. The rear tray had one of the bracket screws missing, so it was hanging a little low on the driver's side too.

So, I went to my local dealer to get all the original fasteners and do it right. That lasted through a couple oil changes, fighting with those little tinnerman nuts and the screws that aren't long enough after you bottom the front spoiler a couple times.

Out came the nutsert tool. Nutserts are threaded inserts similar in principle to pop rivets, but with a threaded hole in the middle. It takes a dozen of these to replace all those tinnermans, giving you a real threaded hole to stick real machine screws into. I left the sheet metal screws into the frame rails, but may come back later and tap those holes out so that all the screws are the same.

Nutserts are commonly available in US sizes, but can be found in metric if you search hard enough. I used 10-32 inserts because I had them in stock at home, along with some stainless machine screws and washers from the boat bin. The only disadvantage of stainless is that the magnetic screwdriver won't hold them for the two that go up inside the NACA ducts behind the rack.

Look at industrial hardware stores, race shops, etc for nutserts. They go by a few different trade names so search by description. The simple tool they supply for installation is slick and inexpensive.

Anyway, that's the solution I found. After seeing that the trays are $hundreds to replace, it made the extra effort suddenly worth while.

dr bob