What is the socket size for the rear hub nut on a beetle?

it's 36 mm and you will need a 3/4 inch T-bar and the socket to go with it as well as a nice long cheater bar 2 get it off the help of a heavy friend will be handy.

There is also a Tool that you can buy that you can use one person and a 3/8" socket wrench with it. It's about $60.00 (US). If you plan on keeping the car, BUY it or keep it and rent it to your friends. It involves a set of gears and it's great for putting the hub nut back on. You can accurately torque it instead of guessing. It will also remove the flywheel nut.

But follow the directions as you can OVER torque the nuts with it.

Just search the internet for "Torque Tool Flywheel & Drum plate kit"

thesamba.com, cip1.com, etc....