This writeup is probably major o****ill for such a simple fix, but this question gets asked about twice a week so I figure it's time we had one of these. At any rate, the random squeaking noises when turning my steering wheel finally became unbearable. I couldn't really find a good writeup, so I tore into it and here's what I found.
As far as I can tell, there are only three things that can cause this noise. I would check them in this order:
1. Bearing at bottom of steering spindle
2. Bearing at top of steering spindle
3. Steering wheel slip ring
If you take your car to the BMW dealer with this problem, they will replace the slip ring, which will set you back about $300 and probably won't fix the noise... or it may actually seem to fix it for a week or two until it decides to come back. Speaking from experience on this one. Your best bet is to start with number one and work your way down.
Perform any of the following at your own risk. As always, follow basic common-sense safety procedures, especially when it comes to jacking up your car.
So here we go...
Steering Spindle Bearings
This is what the steering spindle assembly looks like. The lower bearing, number 7 in the diagram, is the most common cause of the squeak. The spindle itself is actually hollow, so even though the lower bearing is down in the engine bay below the firewall, any noise it makes will echo through the steering spindle shaft up into the car's interior. The result is a squeak that sounds like it is coming directly out of the steering wheel.
To lube the lower spindle bearing, you will need the following:
- floor jack and jackstands
- can of Tri-Flow or equivalent penetrating lubricant (NOT WD-40!!)
- three flexible party straws (see pic)
- duct tape
- safety goggles
There's no good way to access the lower bearing, because it sits just below the firewall way up in the engine bay. In order to get to it, you're going to need to use the party straws and duct tape to fabricate about 18 inches of extra tubing attached to the end of the lubricant spray can.
I bought a package of thin party straws with flexible end segments at the local supermarket for $0.58. These work well because the very tip of your 18-inch tube will need to bend slightly in order to get a clear shot at the bearing. Get the thinnest, smallest diameter straws you can find:
Jack the front of the car up, support with jackstands, and wriggle under there until you see where the steering shaft exits the firewall. It's way up in there, at the top of this thing:
Shake the can of Tri-Flow or other lubricant up REALLY good... You need to build up some pressure in order for it to shoot all the way up there. Attach your extension and manuever it until the tip is pointed right at the steering spindle assembly where it pokes out of the firewall. Then, soak it! (I recommend wearing some safety goggles while you do this... There's a good chance some of this stuff will drip down into your eyes/face.) At this point you may want to turn the steering wheel lock-to-lock just to make sure everything gets coated properly, then spray the bearing down again just to make extra sure.
Once that bearing assembly is good and drenched with lubricant, lower the car and take it for a drive. Do whatever you normally do that makes the steering wheel squeak... For me it was sharp low-speed turns like parking maneuvers. Listen for the squeak. If it's gone, great! If not, proceed to #2...
Next we'll tackle (2) the upper spindle bearing and (3) the slip ring. You will need:
- Bentley manual (not absolutely essential, but the photos are helpful if you've never removed the steering wheel before)
- ball-point pen
- metric socket set
- T30 Torx key
- felt marker, ultra-fine tip
- more Tri-Flow or equivalent
- copper paste lubricant (aka grease)
- torque wrench
This procedure involves removing the airbag. PROCEED AT YOUR OWN RISK.
Break out your Bentley manual and follow the instructions to remove your driver-side airbag and steering wheel. It goes something like this.
Start by parking your car with the steering wheel centered and the front wheels pointed exactly straight ahead. Then:
1. Disconnect negative battery terminal
2. Remove lower steering column trim mounting screw and remove lower trim. The screw is at the very bottom of the underside of the steering column. Remove it and then remove the plastic trim piece that covers the bottom half of the steering column. You'll need to push your cruise control lever around to get the plastic piece out without breaking it, but it will come out.
3. Remove orange SRS connector from its holder and carefully separate connector. There's a tiny little tab you'll need to press in on the side... use a ball-point pen. The connector should slip apart.
4. Working behind steering wheel, completely loosen Torx screws (T30) while holding airbag in place. Support airbag to prevent it from falling out. These scews are a PAIN but they WILL come loose if you're patient.
5. Carefully lift airbag off of steering wheel and disconnect orange harness connector from rear of airbag unit. Mine just pulled straight off. Be careful to set the airbag down face-up, someplace out of the way.
6. Now remove the steering wheel center bolt, number 6 in the diagram. If I recall correctly you'll need a 17mm socket here.
7. Now you can see the tip of the hollow steering spindle through the middle of the steering wheel. The outer edge of the spindle is toothed where the wheel slides over it. Use an ultra-fine tipped marker or something similar to mark the exact position of the steering wheel relative to the steering column shaft; that way you can put the steering wheel back on in precisely the same position later.
8. Unlock steering wheel by turning ignition key on. Remove steering wheel.
Now you can see the top part of the steering spindle assembly. Break out your can of lube and go to work. Give it several good shots and rotate the bearing and snap ring as you go to make sure the lube works its way in all around. Mop up excess.
I'm told that in some cases, the plastic bearing (#2 in the diagram) can be worn out, causing grinding and/or a wobbly or loose-feeling steering wheel. So, take a good look at the bearing while you're in there. If yours looks like it's on its last legs, you might consider replacing it. (Thanks to Kevin/KTL for the info.)
On the back of the steering wheel you can see the slip ring. Give it a light coating of copper paste lubricant.
Now it's time to put everything back together:
1. Install steering wheel while aligning matching reference marks you made earlier. Make sure airback contact ring locking pin engages cut-out in contact reel. (See the Bentley manual for photos... The pin is white and plastic and fits into a small hole in the ring in back of the steering wheel.) Install steering wheel center bolt and torque to 46 ft-lb (63 Nm).
The rest is simply the reverse of removal: Re-attach orange harness connector to back of airbag. Replace airbag and tighten the two airbag mounting screws in back of the steering wheel. Re-attach the orange SRS connector. Replace lower steering column trim. Replace trim retainer screw. Re-connect negative battery cable. Then follow the normal procedure for re-activating your auto-up windows, radio code, etc. You're done.
Take your car for another drive and enjoy the squeak-free silence.
I've found this entire procedure also reduces steering effort and helps isolate the steering wheel from roadgoing vibrations. My guess is this will all have to be repeated every 50-70k miles or whenever the lubricant dries up again.
