Gen 3: Replacement Seat & Seatbelt Anchor Bolts - what's the right size?

Roger, I can't find M11 x 1.25 and as far as I am aware the nearest sizes are M11 x 1mm or M11 x 1.5mm.

7/16 UNF is 11.1mm diameter with a pitch of 1.27mm. Both UNF and metric are 60 degree angles so 7/16 UNF would be almost impossible to tell apart from M11 x1.25mm if it exists.

I am not sure how secure a fit you would get if you screwed a M11 x 1.25mm in to a 7/16th UNF always assuming it would actually screw in.

Hi Doc.
From memory, seat belt fittings used an odd size to prevent unauthorised people from fabricating their own, possibly dangerous, mounting points.
Try calling a Mr. Wadishaw on 0208 888 1865. This is the Tap and Die co. at 446 West Green Road, London N15 3PL.
If he doesn't know, nobody knows!

Roger

Just checked with a local nut and bolt supply co. and they say the universal thread size for seat belt mountings is 7/16 UNF.

Roger

Back in the day when things where not so dangerous, my SJ was approved by the Norwegian departement of roads, with one seat belt from a Niva and one from a Opel Rekord. I was a bit worried about the kyrrilic russian letters on the one belt. But it was all ok and the SJ was changed from a commercial to a 4 seater.

All and any seat belt bolts will fit.

Decided to give cleaning up my existing bolts a go instead of worrying about buying new ones. I put them in white vinegar for about 48h and gave a tidy up with a wire brush and they came out looking remarkably fresh! I have also primed them with a LIDL aluminium zinc spray (only on the top, not on the threads) just to freshen them up.

If they all fit nicely in the new boot crossmember then job done. Otherwise I'll try some replacements! Also painted my corroded rear set anchors black (after sanding off the surface rot).

See pics!