C3 Seat Belt Bolts

[Joe L.]

I'm interested in the external configuration of C3 seat belt bolts (the one securing the outer belt which can be seen on the bottom of the floor boards). Of course, most of the bolt cannot be seen. However, the bottom of the bolt can be easily seen under the car. Attached is a photo of an original bolt on my 1969. This bolt has a tapered pilot (i.e. the configuration at the end of the bolt). I'm curious as to what configuration may be seen on other C3's, especially 70-76 models. This is really easy to see or photograph looking under the car.


DSCN2990.jpg

[Tom R.]

Re: C3 Seat Belt Bolts

I have the bolts on a 78 removed and have another still in place. Are you interested in the plate/nut that secure the bolt or just bolt?

[Kurt G.]

Re: C3 Seat Belt Bolts

Unless I'm grossly mistaken the bolts are the same in the later models.

[Alan S.]

Re: C3 Seat Belt Bolts

Hi Joe,
On my 71 the seat belts are mounted through the sides of the underbody on both the outer and inner belts.
Here's a picture of the bolt…. mid-January built 71. No taper.
Here's the inner bracket showing the non-tapered bolt installed. The outer mount is now up along side of the rocker channel and can't be seen when the body is on the frame.
Regards,
Alan

[Edward J.]

Re: C3 Seat Belt Bolts

Joe, My 72 car is on a lift and took a look and the bolts are as Alan's

[Tom R.]

Re: C3 Seat Belt Bolts

These are the seatbelt bolt anchors from a 1978. The short one is top...while the longer is the lower bolt as evidenced by the wear. These are metric torx bolts a I recall...I think the size was 50mm. They were plated with pastel blue...lightly.

DSC03793.jpgDSC03794.jpgDSC03796.jpg

[Lawrence M.]

Re: C3 Seat Belt Bolts

Joe,

The bolts on my last week of production (Dec 15) 69 appear as yours.

[Joe L.]

Re: C3 Seat Belt Bolts

I have the bolts on a 78 removed and have another still in place. Are you interested in the plate/nut that secure the bolt or just bolt?

Tom------


Mainly the bolt but the nut plate might also be interesting.

[Joe L.]

Re: C3 Seat Belt Bolts

I'm also interested if any C3 is found to have seat belt bolts with a pilot configuration as seen in the attached photo:


GM #3977719(repro2).JPG

[Pat M.]

Re: C3 Seat Belt Bolts

Joe, my May built 70's bolts have heads like Alan's bolts, and my inner bolts appear to have tapered ends like yours. I can't see the ends of my outer bolts.

[John H.]

Re: C3 Seat Belt Bolts

I'm also interested if any C3 is found to have seat belt bolts with a pilot configuration as seen in the attached photo:


[ATTACH=CONFIG]53724[/ATTACH]

Joe -

In the plant, that was called a "dog-point" bolt. In 1968, I developed and patented the "roll-point" bolt jointly with Anchor Fastener, which rapidly became the assembler and repairman's best friend.


RollPointBolts.jpgRollPointBolt.JPG

[Joe L.]

Re: C3 Seat Belt Bolts

Hi Joe,
On my 71 the seat belts are mounted through the sides of the underbody on both the outer and inner belts.
Here's a picture of the bolt…. mid-January built 71. No taper.
Here's the inner bracket showing the non-tapered bolt installed. The outer mount is now up along side of the rocker channel and can't be seen when the body is on the frame.
Regards,
Alan

Alan------


I presume this bolt to be a GM #3977719. This is the bolt that was supposed to have been used for 1970 through at least 1972. Note how the end has no pilot, at all. Note how the end differs from the bolt in my photo. I just cannot imagine why GM would have gone to a non-pilot bolt after 1969 but, apparently, they did.

[Joe L.]

Re: C3 Seat Belt Bolts

Joe, my May built 70's bolts have heads like Alan's bolts, and my inner bolts appear to have tapered ends like yours. I can't see the ends of my outer bolts.

Pat-------


It must be that 1970's used the same bolt as 1969 even though the AIM does not indicate that. I'm pretty confident that Alan's bolts are the GM #3977719.

[Joe L.]

Re: C3 Seat Belt Bolts

These are the seatbelt bolt anchors from a 1978. The short one is top...while the longer is the lower bolt as evidenced by the wear. These are metric torx bolts a I recall...I think the size was 50mm. They were plated with pastel blue...lightly.

[ATTACH=CONFIG]53716[/ATTACH][ATTACH=CONFIG]53717[/ATTACH][ATTACH=CONFIG]53718[/ATTACH]

Tom-------


Yes, apparently for 1978 GM began using metric bolts for the seat belt anchor bolts. 1978 marked about the beginning for "metricification" of US-manufactured vehicles. Thereafter, the process proceeded inexorably.

I believe there's one last bastion of US/SAE size bolts in the GM stable for PRODUCTION vehicle components. Does anyone know what it is?

[Alan S.]

Re: C3 Seat Belt Bolts

Hi Joe,
The 71 AIM lists 3977719 as the part number for the seat belt bolt and 3956042 as the part number for the shoulder strap reel mounting bolt.
Regards,
Alan