Upper seat belt bolt/nut question

Hi Mikael,

There should not be a nut in the engine compartment. If there is it may be because the threads have stripped out of the original captive plate and that's a pain in the butt. You could Helicoil it but I think you would have to drill a hole all the way through the box section otherwise you will not be able to get the tap through to cut the new thread. But If you have a nut then maybe someone has already drilled all the way through? Other than that you would have to cut the box section open and weld in a new captive plate.
This is very easy all you have to do is pop the engine and tranny out!


The bolt is 7/16 UNF. This is the standard seatbelt bolt size across the industry even used on Japanese cars and still used in all modern cars as far as I know. Sometimes they put a metric head on it but it's always a 7/16 UNF thread. It's also the same size as the drive shaft bolts except they use a 5/8th head.

If you have any trouble finding the right bolts let me know I have lots. Whenever the garage next door to my workshop scrap a car I always strip out all the seat belt hardware.

If you buy a Kirk Evans firewall kit you will not have to remove the entire bulkhead to access the engine because it has a removable centre section so you never need to undo the seatbelts. I installed one of these in my friends car and highly reccomned it.

Merry Christmas!

Johnny

Hi Johnny
Yes, I'd like two bolts if you have with proper threads and length. I'll pm address.

Not sure what a Kirk Evans firewall is. I've seen pictures that allow the passenger seat to go further back, but can't see the alternator. I want to keep all the noice reduction I can, my car is very noisy.

Helicoil won't give me peace of mind, since this thread might one day be the difference between life and death for me or a family member. So either if you have the right bolts and threads are fine, or I'm back to my idea of inserting the bolt from the engine room, and securing the seat belt bar with a nut. And I need some sort of positive lock for that nut.

Merry christmas, say hello to the artist.

Mikael,

You may (hopefully) get lucky and find the previous owner didn't have the correct bolts and just used a smaller nut & bolt leaving the old threads intact. It is pretty hard to strip out those fine UNF threads.

I believe in most Country's it is a DOT requirement to have the bolt thread into the chassis/body and that removable nuts are prohibited.

The 'captive nut' on my '74 is actually a piece of threaded tube welded into the box section, it does not go all the way through to the engine compartment. I would think it possible to cut this out and replace from the cabin if necessary. The tube is very thick wall and IMO you could probably retap it a slightly larger size. If so use an equally fine thread.

Are you using conventional seat belts or harnesses?

Good luck,
Julian

Hi Julian, here's a picture from earlier, still have the belts. Roll bar is replaced with seat belt bar now.

The stock shoulder harness bolts have a long unthreaded shoulder but are otherwise a std metric bolt. Over the years I've found the darndest mods when one or both the stock bolts go missing- including lead concrete anchors pounded into the tubes and grade-nothing lag-bolts holding a shoulder harness bar! I was able to drill them out and underneath, the stock threads at the back of the tube were just fine. This guy was apparently all into appearance and had complete faith he would never run into anything.... New owners, CHECK EVERYTHING! You never know who's been digging into the car.