Hi: 2004 MCS, 156K, OE sport suspension. I need to replace the original OE rear sway bar bushings. Bentley's describes a bizarrely complex procedure by which the rear subframe and gas tank are lowered. First Question: Is that necessary? I hope not, since I am not replacing the entire bar, just the bushings. Second question: What is the diameter of my OE, R53, sport suspension rear sway bar? Third question: What bushings do people recommend? Powerflex, OE, or anything from one of our vendors? Thanks.

 

I can tell you both sides are easily accessible after wheel removal without any other work. I fitted regular OEM stock but as for size, etc, cannot help.

 

The R50 OEM RSB is 16MM.
The R53S is 17MM
For future reference go to: http://www.realoem.com/bmw/enUS/select

 

Your choice between OEM and polyurethane however, you're not going to feel much difference in response with either. OTOH, install a rear bar with poly bushings and your car will handle much better. BTW, it's not an overly difficult job to install a thicker bar.

 

There is no need to drop the subframe when replacing the rear swaybar bushings. The brackets are easily accessed through the wheel well with the car jacked up and the wheels removed. F.Y.I. - polyurethane bushings will transmit more road noise into the interior.

 

Stick with the OE rubber bushings, and also remember to have both rear wheels in the air to take load off sway bar.

My advice for easier access to the two bolts that hold the bushing brackets in place (especially the more forward of the two) is to remove the rear struts. Not particularly difficult, a single bolt at the strut bottom is all that needs to be removed to drop them, and the time saved by having full access to the two bushing bracket bolts (as opposed to wrenching them off and on in teeny-tiny arc increments) is worth it. With the struts in place, you can't get a ratchet socket in place as it's pretty tight quarters to get in on the bolts. With the struts removed, much easier.

This video shows the painstaking process with struts in place. If the bolts are rusty it makes it even more difficult.

 

Use stands. Jack it up from the front pad on both sides and slide a stand under the rear pad. DO NOT get under that rear end with it up on jacks alone. You may already know this but it doesn't hurt to be reminded, in the heat of battle some things get forgotten.