What is the thread for the Sierra seat belt bolts. I want to buy some nuts to weld to the chassis or a tap to to thread some plate to weld on.

Hi Ewan,

This is an old chestnut (no pun intended). All seatbelts on UK cars are held in place with 7/16 UNF thread - and I have checked this with both thread gauge & tap.

There is a strictly non-standard metric thread M11 x 1.25, which is an approx equivalent to 7/16 UNF (provided that there are generous grades of thread fit). The UNF will be easier to obtain.

Dick

i still have a box of nuts somewhere in my shed that are the right ones for the belt. They are unplated steel and easy to weld to comply with sva captive requirements.

I can post you a few if interested.

atb

steve

Thanks Steve but I ordered them about 2 minutes after Dick posted the reply. Ordered from www.namrick.co.uk for 18p each.

Much appreciated though.

Ewan.