New lower control arm front ball joint nuts are needed for assembly. To start with, one should place a block on the rear wheels, engage the parking brake, lift the front part of the car and support it by means of jackstands and finally remove the correct front wheel. Then, unscrew the splash shield to undo if from the screws, and finally unscrew the bolts to undo the reinforcement cross brace/plate located below the vehicle. For the models with suspension ride height sensors, now, the retaining nut needs to be unscrewed and the sensor link bracket needs to be detached from the lower arm. Loosen of the lower arm balljoint nut and free the arm from the steering knuckle by using a universal balljoint separator, while holding of the balljoint with the Allen key before nut removal. Undo the two bolts that fix the lower arm rear mounting bracket to the chassis, then unscrew the nut in the inner balljoint of the arm and raise the lower arm assembly out from under the car: the balljoint is likely to be tightly pressed into the crossmember and may need to be tapped out. Wash the lower arm and the adjacent zone and inspect the area for cracks, distortions, or other signs of wear, particularly in the mounting bushings and ball joint; if necessary, you should take the lower arm to a BMW centre or to a garage equipped for replacing the bushes as they should be pressed in. For installation, first, make certain that the balljoint studs and mounting holes are clean and dry, then align the lower arm, by engaging the inner mounting stud to the crossmember; then the balljoint stud with the steering knuckle while using the jack to pull the inner balljoint stud into place. Thread on a new nut to the inner balljoint stud and tighten it to the specified torque; then do the same to a new outer balljoint stud. Replace the bolts of the lower arm rear mounting bracket and torque it, in case you have models with the suspension ride height sensors then replace the sensor link bracket and tighten the nut. Last of all, replace the reinforcement cross brace or plate and torque the bolts, replace the engine splash shield, fit the wheel, lower the car and torque the bolt of the wheel.
