Self-locking hex nut — a genuine BMW part, number 61 13 8 367 755. The number stamped on the part is 61138367755; BMW's catalog files it under the short number 8367755. You will find it on our Electrical shelf, under Plug connection, terminal. BMW has since replaced it with 7575164.
It fits every E46 body style (320i, 323i and 325i, 1999–2006), with the M52, M54 or M56 engines — and the European-market versions.
BMW draws it on 4 diagrams, among them Battery Cable(battery Rear) (61_1108) and Battery Cable (61_1628).
We have not had one on the shelf yet. Request it and we will tell you when one comes off a car.