BMW E36, E46, Z4 Camber Adjustable Rear Control Arm (RCCA) Install – How To, DIY
The E36 (3-series 92-98), E46 (3-series 99-05) and E85/E86 (Z4 03-08) BMW models all have a similar trailing arm rear suspension design. BMW has provided a small amount of rear camber adjustment at the outer mounting point for the lower control arm by using a slotted hole in the arm and an eccentric washer on the through bolt. When the suspension is lowered, this adjustment is no longer adequate for camber adjustment if long tire wear is a desired goal.
Bavarian Autosport offers two options that allow an increase in camber adjustment range. One is a urethane bushing that replaces the stock bushing at the camber adjusting location (in the lower wheel hub) and provides an increased range of camber adjustment. This bushing must be pressed into the hub eye after the stock bushing is pressed out (press tools included in the kit). The second option is to replace the stock lower control arms with our adjustable billet aluminum lower control arms. These arms are a direct replacement for the original arms and provide all of the adjustment that could ever be needed (more than the replacement urethane camber bushings). Additionally, once the arms are installed, they are easier to adjust.
This How-To write-up is directed at installing the Bavarian Autosport (www.BavAuto.com) Camber Adjustable Billet Aluminum Rear Lower Control Arms (LCA, RLCA). See our article on BMW camber and caster issues HERE.
Vehicle lift or floor jack and jack-stands.
16mm through 21mm 1/2″ drive sockets, extensions, wobble joints, ratchet and breaker bar.
16mm through 21mm combination wrenches or ratcheting combination wrenches.
1/2″ drive torque wrench.
NOTE: This procedure is performed on a non-M3 E46 3-series (99-05). The E46 M3, E36 3-series (92-98 except 318ti and Z3) and the E85/E86 Z4 are similar, with minor differences in the differential mounts.
Before beginning, disassemble the new adjustable control arms and liberally coat all of the threaded areas and parts with anti-seize compound. Reassemble the parts. Thread the ends onto the center bar evenly so that there are the same number of threads showing on each end of the bar. Specific length does not matter at this time.
- Raise and safely support the rear of the vehicle, with the suspension hanging free (wheels off the ground).
- Remove the wheels.
- Remove the outer through-bolt for the lower control arm outer bushing (this is where the stock camber adjustment is made). Use a pry-bar inserted into one of the lower holes in the trailing arm to pry the arm and hub outward, relieving tension on the bolt. Note to turn the bolt so that the offset washer at the head of the bolt will more readily clear the brake backing plate. Do this for both sides.
- Spread the two “forks” of the control arm and pull the end of the arm off of the bushing and lower the end of the arm (use the pry-bar, as noted in step-3 to relieve the hub’s inward compression on the arm). Do this for both sides.
- NOTE: In order to fully remove the lower control arm inner mounting bolts, the differential must be moved rearward a small amount. This requires partially or fully dismounting the differential from it’s subframe mounting points. Continue below for details.
- Support the differential with a floor jack and remove the rear differential mount bushing through-bolt. The floor jack is used to ease the removal (and installation) of the rear mount bolt.
- Loosen the two front differential mount bolts. Thread out the bolts about 1/2″ to 3/4″, but do not allow the bolt to be fully removed from the differential threads. Push the differential rearward as the bolts are threaded out.
NOTE: The E36 models and the E46 M3 have different mounting points for the differential. On the E36 models, you must fully support the differential with a floor jack and remove the one front and two rear mounting bolts, in order to perform the following steps.
- Loosen and remove the lower control arm inboard mounting bolts. Pry the differential rearward and to the left or right in order to provide clearance for the bolts to be fully removed. Note that there is a captive tab nut at the front of the subframe, that each bolt is threaded into. The tab nuts will fall out or you will need to “fish them out” with your fingers or needle-nose pliers.
- Pull the inner ends of the lower control arms out of the subframe and set the arms aside.
- Match the original control arms to the new adjustable arms. Turn the center rod clockwise or counter-clockwise to lengthen or shorten the control arm so that the bolt through holes are at the same length from inner to outer, as the original arms. This will just be an initial setting that will allow the car to be driven to an alignment shop or to act as a starting point for DIY camber adjustment.
- Insert the inner end of the adjustable control arm into the subframe and insert the through-bolt (prying the differential as required). Repeat for other side.
- Insert the tab nut into place using needle-nose pliers, and thread the bolt into the nut tab. Once the bolt is started threading into the nut tab, you can remove the pliers. Do not fully tighten the bolt. Repeat for other side.
- Install the forked end of the adjustable control arm over the outboard mount bushing, in the wheel hub. Pull the lower part of the hub outboard until the fork can be positioned over the bushing (use a pry-bar as noted in step-3 above). Insert the through-bolt and nut. Do not fully tighten. Repeat for other side.
- Remount the differential. In this case (non-M3, E46 models), push the differential forward and insert the rear bushing through-bolt. Next, thread-in and tighten the two forward bushing bolts. Finally, install the rear mount nut to the bolt and tighten. On the other models noted (E36 and E46 M3), use the jack and a pry-bar to reposition the differential and install the mounting bolts and nuts as required.
- Tighten the adjustment lock-nuts to the inner and outer ends of the arms (unless you will be performing a DIY camber alignment at this time).
- Install the wheels and lower the rear of the vehicle to the ground. Move the vehicle forward and rearward a few feet (to settle the suspension). Tighten the inner and outer lower control arm mounting bolts. This can be done with the vehicle driven onto ramps or a ramp lift, if chassis clearance is too low.
- As soon as possible get the vehicle to an alignment shop to adjust the rear camber (and the toe). For daily street driven vehicles, where tire wear is the most important desire, we recommend 0.25 degrees of negative camber and 0.05 degrees of toe-in, for each side (0.10 degree of toe-in, inclusive; total of both left and right).