Every BMW is built to be competent on some twisty roads. It shouldn’t be a surprise that the M-badged cars receive the best suspension components in terms of handling precision, BMW engineers. The E90 generation M3 was an immediate success, lauded for its sharp handling characteristics and shrieking V8. Luckily for E9X owners of non-M cars, the M3’s front suspension arms directly swap over into any E9X chassis.
Whether you’re upgrading to the M3 arms or keeping them stock, the replacement process is going to be the same. Contrary to a lot of BMW jobs, replacing the arms doesn’t require any special tools. Follow the steps below to ensure you replace the arms correctly the first time around.
BMW models and years applicable:
Symptoms of worn BMW E90 front suspension bushings:
- A clunking sound coming from the front of the vehicle
- Uneven tire wear
- Instability under braking
- A wandering feeling during cornering
As the bushings in the front arms wear, the rubber in them becomes significantly squishier. Also called deflection, the increased slop causes a greater variance of dynamic toe angles while driving. That can lead to a numb or slightly squirrely feeling from the front of the car. The steering feel can be characterized as numb, while the vehicle may pull to one side during braking.
The M3 arms also feature a stiffer rubber bushing in the tension rod and a Heim joint for the lower control arm’s inner pivot. The change from the stock rubber bushings will increase the feel and handling capabilities while also increasing the NVH felt throughout the car.
How much will it cost to replace BMW E90 front control arms?
TRW sells a kit that will replace the front control arms on your BMW E9X with those of the M3. The bushings are stiffer, and the geometry is changed to allow for a more precise steering feel and response. The kit costs around $330 and is all you’ll need to replace and upgrade your front control arms.
How long will it take to replace BMW E90 front control arms?
Even with having to deal with corroded parts, replacing the arms shouldn’t be too long of a job. Set aside an hour for each corner of the suspension.
Parts required to replace BMW E90 front control arms:
Tools required to replace BMW E90 front control arms:
- 8mm Socket
- 10mm Socket
- 17mm Socket
- 18mm Socket
- 9mm Wrench
- 18mm Wrench
- 21mm Wrench
- T40 Torx Bit Socket
- Torque Wrench
- Pry Bar
- Brass Punch
- Deadblow Hammer
- Flathead Screwdriver
Steps required to replace BMW E90 front control arms:
Step 1: Remove the control arms
Jack up the front of the car and place it onto jack stands. Then, use a 17mm socket to remove the lug bolts so you can remove the wheel. With that out of the way, partially remove the fender liner and the splash shield.
The inner mounting bolt for the tension rod sits behind the fender liner. To access it, you must loosen the fender liner and move it out of the way. Use an 8mm socket to remove the three fasteners from the forward portion of the fender liner and the two from the splash shield below the fender.
Next, use a 21mm wrench to remove the nut securing the lower control arm to the knuckle. You’ll be able to break the nut loose, but the nut will eventually start to spin the ball joint stud. Use a T40 Torx bit socket to counter hold the stud as you loosen the nut.
Loosen the nut until you can pin to off with your fingers, but don’t remove it completely. Just inboard on the knuckle is the tension rod’s ball joint nut. Use the same wrench and T40 Torx bit socket to remove the nut from this ball joint.
Next, peel back the fender liner and splash shield to get to the tension rod’s inner mounting bolt. Use an 18mm socket to remove the inner mounting bolt. Pull the tension rod down and out of the subframe to remove it from the car.
After that, use an 18mm socket to remove the bolt from the lower control arm’s inner pivot while counter holding the bolt head with an 18mm wrench. Then, unclip the headlight leveling sensor arm from the driver’s-side arm.
Pull the old arm down and out of the car.
Step 2: Install the new lower control arm
Take the new arm and fit its inner pivot into the subframe. It will be a very tight fit, so you may have to use a dead-blow hammer to knock it in.
Align the hole in the pivot with that in the subframe and slide the mounting bolt through. Thread on the nut by hand and then fit the arm’s ball joint into the knuckle. Thread on the ball joint’s nut by hand.
Step 3: Install the new tension rod
Remove the old nut from the subframe for the tension rod. The nut sits in a small clip that aligns itself on the subframe. Remove the old nut and replace it with the new one included in the control arm kit.
Then, install the new tension rod. Ensure the outer half of the arm is positioned over the tie rod and into the knuckle before fitting its inner pivot into the subframe. This inner pivot won’t be as tight as the lower control arm’s, so you shouldn’t need the dead blow for this.
Thread in the tension rod’s inner bolt, but don’t tighten it. Next, take a 21mm wrench and the T40 bit socket, and tighten the ball joint nuts. Use the 21mm wrench to tighten the nuts while counter-holding the ball joint stud with the T40 Torx bit socket.
Step 4: Torque the nuts and bolts
Tighten the nuts for both ball joints. Then, use a 21mm Socket to torque the nuts to 175Nm.
Next, move to the lower control arm’s inner pivot. Examine the bolt head and look for the hardness rating. You’ll see either 8.8 or 10.9. If your bolt says 8.8, torque it to 68Nm, plus 90°. Torque a 10.9 bolt to 100Nm, plus 90°. Either way, use an 18mm socket to torque the nut while counter-holding the bolt head with an 18mm wrench.
The M3 style lower control arm uses a sealed Heim joint for the inner bushing; therefore, it doesn’t have to be at ride height when you torque it. If you’re installing the non-M arms, ensure you raise the suspension to ride height before torquing this inner bolt.
After that, raise the suspension to ride height. The tension rod’s inner bushing is still rubber, so you must torque it at ride height. Use an 18mm socket to torque the bolt to 68Nm, plus 90°.
Step 5: Install the new headlight leveling arm
Most cars come with self-leveling headlights. The lights are controlled by an arm that connects to the lower control arm, which senses the up and down movement of the suspension. The M3 arms use a different style of leveling arm that you now need to install.
Take the new arm and mount it to the headlight leveling sensor. Counter-hold the stud with a 9mm wrench while tightening the nut with a 10mm socket.
Then, position the lower portion of the arm into the lower control arm. Slide the stud through the hole on the control arm and then thread on the nut. Counter-hold the stud with a 9mm wrench while tightening the nut with a 10mm socket.
Lastly, resecure the splash shield and fender liner fasteners with an 8mm socket. Then, refit the wheels and lower the car to the ground. Use a 17mm socket to torque the lug bolts to 120Nm.
BMW E90 Control Arm Torque Specs:
- BMW Ball Joint Nuts = 175Nm or 129 ft-lbs, of torque
- BMW Lower Control Arm Inner Bolt (8.8-Spec) = 68Nm or 50 ft-lbs of torque, plus 90°
- BMW Lower Control Arm Inner Bolt (10.9-Spec) = 100Nm or 74 ft-lbs of torque, plus 90°
- BMW Tension Rod Inner Bolt = 68Nm or 50 ft-lbs of torque, plus 90°
- BMW Wheel Lug Bolts = 120Nm or 89 ft-lbs, of torque
With your new M3 front control arms, your BMW E9X is ready for the nearest track day or twisty mountain road. If you're interested in more DIYs for your BMW, you can visit bmw.fcpeuro.com and subscribe to our YouTube channel.
Owner of a flat-six swapped 1998 Impreza 2.5RS and a 1973 Porsche 914. Horizontally opposed views, only.