1999 Buick Lesabre removing driveshasft pulley

First you’re going to need a better socket.
And try it again.

I normally don’t recommend this method to people, but I’m sure you are getting to your wits end. You’re probably still frustrated from trying to track down that knocking sound (I’m assuming that’s why you want to replace the HMB)

Get your socket, your breaker bar, and maybe even a piece of pipe big enough to fit over the breaker bar handle.

You are going to put the socket and breaker bar on the big bolt in a way that the handle is going to rest against something solid like the control arm, or frame of the car.
REMEMBER the HMB is going to be turning clockwise.

Now get in the car and bump the key for a split second.

The starter motor will turn the crankshaft clockwise, the breaker bar cant move because it’s against something solid, so the bolt will stay stationary when the crank turns.

Everything normally jumps off and all of the tools land on the floor.
Most of the time, it works on the first try.

If you don’t have an impact gun, this is pretty much the only way you’re going to get that bolt loose.

Good luck

Oops.
Forgot something.

While you are at the parts store getting a better socket,
ask them for Permatex brand valve grinding compound.
Read the label, you want it to be suspended in water NOT GREASE.

Put some of it on the head of your bolt.
The tiny partials in the grinding compound will help keep the socket from slipping off of the bolt head.