Project E46 BMW M3: Part 19 – Powerflex Rear Trailing Arm Bushings and Maintenance
We put on RTABs from BimmerWorld/Powerflex because the car's rear end was getting all over the place!
The rear trailing arm bushings (RTAB) on BMWs are rubber and are prone to cracking. I’ve had them go bad on previous E36 M3s, and the symptoms were simple to discover and quite obvious. One of the easy ways was to accelerate the car hands-free of the steering wheel. If the rear pulled to a side, you most likely had bad bushings.
I didn’t figure it out so easy on this car, however. It wasn’t until I took a high-speed, four-gear turn on an uneven cement onramp that I could feel the rear end dancing around with so much grip from the surface (cement usually has higher grip than asphalt). It was very unnerving, and quickly made me lose confidence in the car.
Upon a quick look underneath, it was obvious the car’s RTABs were wasted. The car just clicked 70k miles, so it was no surprise. We put a call into BimmerWorld, which is Powerflex’s master distributor for all things BMW. I’ve run Powerflex bushings all around on a previous turbocharged E36 BMW M3 with no problem. In fact, I believe it’s the same part number for the E36 and E46 RTABs.
Powerflex comes from Great Britain, and is imported to the USA for all things BMW by BimmerWorld—yeah those light blue and yellow BMW 3 Series you see on TV racing. BimmerWorld recommends replacement of your RTAB if you’re a spirited driver and have a car that has over 50k miles. They run $94 + shipping for the set.
These polyurethane pieces are modular and go together like so. These bushings allow for an easier install, because with a rotating mass there is no pre-tensioning. These particular RTABs should fit all E36 (except ti), E46 and Z Series cars.
With a quick glance underneath the car you can spot the tear in our Project M3’s factory bushing.
It’s that time again so we’ll be doing some maintenance updates using German-made Lubro Moly products from Bavarian Autosport, including 60 weight oil and oil filter, Lubro’s Engine flush to remove carbon build up, and Lubro’s Ceratec lubrication for the internals.