tire tub bolts 1966

[Joe L.]

Re: tire tub bolts 1966

So I removed my spare tire assembly to do a little work on my leaking differential. When I removed the 4 fasteners that secure the tub to the frame. I found 5/16-18 bolts not 5/16-24. I did read other articles that indicated that others also found 18 thread, and yes some previous owner may have changed them before my ownership (have owned this car about 40 yrs). The odd thing is 2 of these bolts have anchor head markings, which I believe is period correct for a 1966. Also the tips are a chisel design with a shoulder under the head. If not correct for the tub where else could these been used? Anyone else found these on their '66? Pics included

Thanks for any comments
Ric

Ric-------


I have no doubt that these screws are original to your car. For one thing, screws of this type, configuration and finish are not the type of thing one would find in a hardware store. Second, the headmarks for those with headmarks are period correct and very unlikely to be found on aftermarket screws. The fact that some have manufacturer's ID marks and some do not means nothing. These things were pulled out of bins by line workers and more than one manufacturers screws may have been in that bin.

These screws are self-tapping and tap their way into the unthreaded holes in the crossmember. I would not attempt to install any other thread pitch screws. Since the holes have already been "threaded" for the threadpitch of these screws you might strip them out. I would also not apply more torque than specified in the AIM when re-installing these screws. To do so might also cause stripping of the threads in the crossmember.

[Richard S.]

Re: tire tub bolts 1966

Thank you everyone for your replies. Joe I was definitely going to use these bolts when I put the tub back and not force a 24 thread into the frame supports. As I said in an earlier post I found it odd that these fasteners met all the criteria other than the shoulder and therefore in my mind could have been there since day one.
It would be nice if other cars were found with the same configuration as the ones I found. Maybe some day.
Thanks again
Ric