Spitfire Spitfire - Seat Belt Anchor Bolts [Size?]

[dklawson]

This should be a fairly simple question. What size should the bolt be for the floor mounted seat belt anchor bolts? My car is a 1972 Spit and a previous owner damaged both weld nuts on the underbody. One has been drilled through and fitted with a large bolt with a heavy hex nut underneath. The other side received a smaller bolt and the DPO put a stainless wing nut on the underneath side.

I'd like to get the proper size bolts. I'm not opposed to using a heavy nut on the bottom side and/or welding in new anchor nuts. I'm working on the floor and now is the time to fix this area.

 

[DougF]

Wingnut? Sounds like someone had a huge life insurance policy on the passenger.

 

[dklawson]

It's even better than just a wing nut. It was a stainless wing nut that was bottomed out on the end of the (too long) bolt's threads. It was not secured against the bottom of the floor with a lock washer or even with Loctite.

 

[Mark Jones]

Doug,

I don't know the size off the top of my head, but the anchor bolt used on the floor is the same size as the anchor bolt on the wheel well (if that's of any help).

 

[Andrew Mace]

Doug, there are any number of companies that have the hardware individually or in kits. One example is Andover, who has various kits at what look to be reasonable prices.

 

[guzzul]

Mine are 7/16" UNF (20 pitch).

 

[dklawson]

Thanks all. I will try to chase the threads in the floor with a 7/16-20 tap to see if they'll clean up. If not, I'll go for 1/2-20 and enlarge the hole in the belt anchor. I may have a couple of spare Grade-8 7/16-20 bolts. If not, I'll try the local nuts & bolts supply places.