"BMW X5 - How to Replace the Lower Control Arm"

By Ron Stultz

22 April 2011

Summary: getting control arm ball joint to separate from steering knuckle can be difficult. Otherwise, easy enough do-it-yourself (DIY).

Background:

BMW X5: Model year 2000, 4.4i, sports package, 149,000 miles.

Time to replace: lower, upper (tension) control arms and sway bar link of front suspension.

Tools needed:

Can of penetrating oil or 3-in-1 Oil

Torque wrench that will do 150 foot pounds (ft-lbs)

Ratchet.

22millimeter (mm) socket.

19mm socket or lug nut wrench.

18mm socket

17mm wrench.

Socket extension

10mm wrench (Believe it 10. Used to remove sensor clamp from control arm.)

Hammer.

Pickle fork.

Note: tried universal ball joint separator but because of angle, no go.

Note: bought special ball joint separator used in limited space but jaws would not open wide enough. So it you go this route, buy or borrow one, that opens a good 4 or more inches.

Good work light. Have to be able to see under car.
 

Car or hydraulic jack.

How to remove old arm:

Set park brake.

Jack up car on side to be worked on.

Remove wheel (19mm lug nuts).

Remove nut from ball joint, steering knuckle, end of lower control arm first (22mm).

22mm nut will be tight.

Once nut removed from lower arm, spray penetrating oil or 3-in-1 Oil around base of exposed ball joint bolt.

On right side (passenger side in United States): remove small nut (10mm?) holding sensor arm to lower control arm.

Remove sensor arm from lower control arm.

Remove nut (17mm open wrench and 18mm socket) on bushing bolt.

There is no car weight on this bolt.

On side with sensor, sensor has a plate on it that goes under the bolt head end of the bolt.

On side with sensor, sensor plate has a hole for the bushing bolt as well as a small tab that sticks into the sub frame bracket so when you reassemble you must get plate to align with both holes in the bracket.

Remove bolt and remove sensor plate.

Getting ball joint to separate from steering knuckle: one one side, couple of hammer blows on arm near knuckle and arm popped free but on other side....... in the end, heat on knuckle (propane torch) and a lot of hammering on pickle fork broke arm free. No good answer here on how you do it, As written by others that have dealt with ball joints, "however you can." But can tell you, be patient and keep hammering on pickle fork.

How to install new lower control arm:

Select correct new arm for the side you are working on. New and old arm should be stamped left or right.

Place new arm ball joint bolt up through steering knuckle and start new 22mm nut by hand.

Place other end of arm up near sub-frame bracket and move about until it fits into bracket and allows bolt to be inserted.

On side with sensor, place bolt through sensor plate and then bolt through sub-frame bracket.

Hand start new 18mm nut on bolt.

Move bolt head all the way through bushing until mates with sensor plate.

Move sensor plate upward until tab on plate mates into hole in sub-frame.

With sensor plate in proper position, place 17mm open wrench on bolt head and use 18mm socket and ratchet to tighten up nut.

When nut becomes snug, check that sensor plate still in proper position.

Tighten nut on bushing bolt to 90 foot pounds (ft-lbs). Unclear what BMW recommended torque is.

Now using 22mm socket and perhaps an extension, begin to torque down the nut on the ball joint bolt.

As there is limited room, will be a while torguing nut down tight against steering knuckle

Again, unclear BMW recommended torque but I used 100 pounds.

On side with sensor, open clamp on sensor arm and place around lower control arm where the arm has a specific place for clamp to mount (clamp goes between 2 ridges on arm)

Tighten 10mm nut on clamp bolt.

Check everything over.

Remount wheel and lower car off of jack.