Before you do all that try this:
ANOTHER METHOD to fix steering squeak
"I drive a 328ic with 159,000 on her. It stopped squeaking at about 130,000 miles. Now it was a grind...
In my case it was actually binding up and making it sometimes difficult to turn the wheel. I could hear a binding/cracking noise from behind the steering wheel.
Thanks to Patrokloss for the great diagrams and the detailed of the real problem i.e.: the lower steering shaft bearings.
Equipped with Patrokloss’s knowledge I discovered the outer steering column is hollow and the bearings are mounted on it. Picture a shower curtain rod with the screw adjustment inside that needs lubrication without using either end. Drill a hole….
THE SOLUTION:
After removing the paneling above the drivers’ feet to gain access to the firewall, drill a 1/32” hole in the outer steering column housing about 2" above the point where it meets the firewall and what I guessed to be a little above the bearings. Spray about 1 ounce of WD-40 in there and place a piece of tape over the hole. That’s it. My grind and squeak was gone….
Don’t drill on the bottom of the housing because the lubricant will drip out. Drill as far up the side as possible. Stick the lubricant straw in the hole and give it a 20 second squirt. The lubricant will saturate the bearings. I am now considering applying a thicker lubricant/grease.
My car steers like new.
Ken Gasper"
I got this from a thread here which has more stuff you can try:
https://www.bimmerforums.com/forum/showthread.php?245961-Steering-wheel-squeak-FIXED-Writeup-w-pics
I used spray grease, not WD40 and it worked. I was convinced the noise was from the top of the column right under the steering wheel as when with the wheel was off it sounded like it was high up but it was down at the bottom somewhere.
Edit: actually may have used grease but I don't think it travelled down the hole to the offending noisy but so I think I sprayed WD 40 too...
Ps your bumper is still in the garage waiting for you!