Replacing rear control arms

[Ricky Bobby]

Originally Posted by Doru

If you check the rear wheels with the air suspension on, the only wiggle you will get, is from the control arms. So you won't know if the rear ball joint is shot. usually the ball joint fails before the arms, but I am speculating here, because that happened on 2 of my BMW's. Maybe on other vehicles it's different?

Anyway, what you have to do is, with the vehicle lifted and secured, you take out the air supply held in place by a clip - it's in the rear hatch left & right below the plastic trays - very easy to access. You have to leave the air connection off, because the car will pump air all the time, even without the key in the ignition. Also, if you change stuff, it's much easier to work with "limb" suspension parts, as opposed to stiffened parts, due to the air bags pushing down hard on the control arms & wheel carrier.
I have the BMW tool (it's a press, which isn't fancy), and it's a very easy job to do with the right tools.

I changed the ball joints only about 2 weeks ago, because the rear could not be "adjusted/aligned" properly, and I would go through tires too often.
it took me about 45 min/side, but to change the ball joint only, once the car is up and you do the other stuff, the procedure to press out/in the balljoints is no more than 10 minutes.

Once you're done, you have to place the air hose (clip) back on, then lower the vehicle SLOWLY. Once the air compressor will start pumping harder, you will hear it humming. That's when you STOP lowering the car, and wait until the hum stops. Then you lower a bit more, and so on. If you let the car all the way to the ground, you can damage the air springs (bags).

Myself, I use Lemforder for all the suspension components on all my BMW's.

Hey Doru, my right rear is not able to be dialed into spec either (currently like -2.9 degrees) but my toe was able to be zero'ed out on both sides in the rear to hopefully save my tires, I'm suspecting the straight guide links are fine as the toe adjustment was ok, but I probably need to do the UCA (wishbone arms) and the ball joints in the rear.

I've heard horror stories about doing the rear ball joints with the carrier on the car (even with the special tool), what was your recommended method to get them done easily, what did you remove?

From what I see, you gotta let the air out of the bag on the side you're working on, take the wheel off, possibly the brakes (can you leave them in place?), disconnect the rear sway bar links, take out the HUGE long bolt that goes through the integral link and ball joint, then that should give enough slack to pull the wheel carrier down so you can remove the integral link and have access to the ball joint?

If you could give some tips I'd appreciate it, I have a local member who has the BMW special tool for removal/reinstall of the rear ball joints who I can borrow it from.