Thread from when I did mine, ....scariest part was drilling out the hole ready for recutting. Drilling into alloy with an electric hand drill not fun.
drmini in aust wrote:
OK today I started to machine up a few steel repair adaptors, as pioneered by 4myego on his Cooper S. (ta for the drawing Steve).
Outside diameter is 3/4 UNF, inside is 5/8 Whitworth.
Pic of the 1st one... (sorry about the crook flash job)
http://home.exetel.com.au/zoomini/zoomi ... GP2330.JPG
You drill and tap the gearbox to 3/4 UNF, clean the thread out and dry it, put some Loctite 262 on the outside of the adaptor, fit the sump plug and torque it up.
The factory may think 25lb/ft is OK, they were in the business of selling spare gearboxes. 15lb/ft would be plenty for a sump plug I reckon.
[edit] If anybody needs one, PM me.

Today I was able to tap my sump out to 3/4 in UNF (as above) and install the steel adapter made by Dr Mini from a design by 4myego.
Very happy with the result.
Big thankyou to 4myego for the original design and to Dr Mini for making up the adapter for me.
Pics.... sorry about the quality.

^^Sump drain drilled out to 17.5mm and tapped to 3/4 UNF ready to receive the steel adapter.^^

^^Original sump plug used to screw in adapter, Thread locker was applied to the thread before installing.^^

^^Adapter installed.^^
