C-3 Rear Deck Lid Hinge Bolts / Screws

[Martin N.]

I was going to start on redoing my deck lid and underside components next week. Does anyone have known original Deck Lid bolts / screws on their C-3 that could post a piccture of them? As you can see (by the picture) "Bubba" used what ever was on the garage floor that day to replace all 4 on my 1974 convertible. The AIM calls out screw #3847758 with a drawn illustration, but I'm not having any luck finding them in the GMPD catalog. I believe these bolt / screws have a washer with them, but is it a flat washer or lock washer? What size should this combination be? Also what about shims for same? My lid will need to be adjusted I'm sure even after new a new weatherstrip is installed. Sorry for the long list of questions, but I'd like to have everything on hand before I start tearing things apart . THANKS in advance.

Marty

[Joe L.]

Re: C-3 Rear Deck Lid Hinge Bolts / Screws

I was going to start on redoing my deck lid and underside components next week. Does anyone have known original Deck Lid bolts / screws on their C-3 that could post a piccture of them? As you can see (by the picture) "Bubba" used what ever was on the garage floor that day to replace all 4 on my 1974 convertible. The AIM calls out screw #3847758 with a drawn illustration, but I'm not having any luck finding them in the GMPD catalog. I believe these bolt / screws have a washer with them, but is it a flat washer or lock washer? What size should this combination be? Also what about shims for same? My lid will need to be adjusted I'm sure even after new a new weatherstrip is installed. Sorry for the long list of questions, but I'd like to have everything on hand before I start tearing things apart . THANKS in advance.

Marty

Marty------


You could look forever in GMSPO information and you'll never find the GM #3847758 bolt. That's because it was never available in SERVICE. GM #3847758 is a 5/16-18 X 1-1/8" hex head bolt. It has a piloting tip (i.e pointed) and a black phosphate finish. It has a captured flat washer and the bolt head is "indented" (i.e. untrimmed). It is GM 280-M material grade (i.e SAE grade 5).

Bolts with captured flat washers or captured lock washers are rarely available in SERVICE. Primarily, they are a PRODUCTION-oriented convenience and are generally considered unnecessary for SERVICE. There were a few available but nowhere near all of those used in PRODUCTION.

Your forwardmost bolt looks like it could be original; the other one (with the trimmed head) is not original.

Attached is a photo of a known-original bolt.