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Replace BMW Upper Control Arms

March 16, 2010

Q I was looking for your write-up on changing the upper control arms (thrust arms) on a 2001 E38, can you point me to this information?

A Since the upper control arm (thrust arm) replacement is covered fully in the Bentley repair manual, we have not yet done a DIY article on this task.

Basically, here are the steps, which generally apply to the following BMW chassis: all E28 (5-series 82 through 88), E34 (5-series 89 through 96), E39 (5-series 97 through 03), late-E24 (6 series 83 through 89), E23 (7-series 83 through 87), E32 (7-series 88 through 94), E38 (7-series 95 through 01), E31 (8-series), Z3, Z4 through 09 :

* Raise and safely support the front of the vehicle, with the suspension hanging free.

* Release the outer ball-joint (on the end of the control arm) from the lower strut/spindle assembly. You can use a ball-joint remover tool, a “pickle-fork” (as long as you are not re-using the control arm, as this will damage the ball-joint boot) or by rapping a 2 to 3-lb short-handled hammer (commonly called a drilling hammer) on the spindle housing where the ball-joint tapered pin goes through. This sets up a vibration that should release the tapered pin. See the Fall 2006 issue of the Bavarian Autosport Fast Times newsletter for additional info on removing the ball-joints (note that this DIY is for a 3-series car and the rest of the procedure is different than that for the BMW models listed in this answer).

* Remove the through bolt that secures the control arm bushing to the frame mounting bracket. On various models you may need to remove the bolts that secure the swaybar mounting crossmember to the frame, and lower the rear of the swaybar for access to the control arm bushing bolts.

* Remove the control arm.

* Install in the reverse order of the removal. Take note of the following points.

** Do not tighten the bushing through bolt until the vehicle’s weight is on the suspension. This can be done on ramps or on the ground.

** If the ball-joint tapered pin turns when you try to tighten the nut, tap the pin into the spindle, from the opposite side of the ball-joint, in order to seat the pin in the hole. As a last resort, you can place a bottle or floor jack under the joint and lightly push it up into the mating hole, then tighten the nut.

Click here for the Fall 2006 issue of the Bavarian Autosport Fast Times newsletter:
http://www.bavauto.com/newsletter/2006_n406_newsletter.pdf

Click here for BMW Bentley repair manuals:
http://www.bavauto.com/se1.asp?dept_id=224

Click here for BMW control arms and bushings:
http://www.bavauto.com/se1.asp?dept_id=162

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