twh

IMO, from the picture, it does look like a welded nut based on the color differentiation between the top and bottom of the hole.

It will be painful to find, but you can find the torque value here: BMW Workshop Manuals

Find your car. Then on the left side, find the subassembly...front axle, for example. Find the bolt. The bolt will have some label on it or in the text like "1AZ" for the torque (it probably won't be 1AZ exactly, but it will follow that naming convention). Then go to the left menu again and go to Tightening Torque. Then click on the subassembly...front axle, for example. Find that same value, e.g. 1AZ.

evolotion

As your in the UK, measure the thread size and ring up your local wurth trade counter for a "time-sert" kit of the correct size. its like a helicoil but IMHO much easier for a novice who has no experience of threaded inserts to install. it will be expensive in that size, ~£70 id think but the kit comes with a hand drill, tap, countersink and insertion tool., if the captive nut in the chassis is spinning, you will need to cut an access window as others have mentioned. Standard practice. I did one just yesterday on a 55 plate mondeo as the captive nut started spinning during a clutch installation.

twh

Time-sert is also an option. I've done both. It might cost more to do Time-sert as you'll need the Time-sert specific drill, tap, insert and Time-sert thread setter/expander. Cost me $100 for the kit I bought for one size to do my oil pan. You'll also need to buy the right length Time-sert insert. The insert cannot be longer than the threaded hole as the last few threads on the Time-sert are what holds it in place.

Stranger12

Many thanks, when we say access windows is that cutting part of the chassis and then welding it back ?

KyleB

Yes.

Can you post another picture from a bit further out than the first one?

BrandonSS

I'd helicoil that and call it a day. The result is going to be a stronger thread than just tapping the existing hole.

Stranger12

sure when I go back to the garage