Ball Joint
 

Note that the ball joint is a "ball and socket" joint. The base of the ball joint (the socket) is pressed into the lower control arm. The threaded/tapered spindle portion of the "ball" extends upward, and attaches to the lower end of the steering knuckle. A nut threads onto the threaded portion and seats the tapered spindle into the steering knuckle. Note that the entire brake caliper/rotor/wheel is attached to the steering knuckle. When you steer the car, the whole steering knuckle rotates at the ball joint. Also, note that there is another "ball and socket" joint at the upper end of the steering knuckle where it attaches to the upper control arm.

Note that when you do this job, you will remove the entire steering knuckle and the lower control arm LCA from the car. You need to use the proper spring compressor to do this. DO NOT USE ANY SPRING COMPRESSOR OTHER THAN THE ONE DESIGNED FOR THIS CAR...IT HAS A CENTRAL SHAFT THAT EXTEND THROUGH THE CENTER OF THE SPRING BY WAY OF THE HOLE IN THE SPRING HUMP IN THE ENGINE COMPARTMENT. YOU THEN SLIDE IN TWO PLATES THAT HAVE CUTOUTS INTO THE SPRING FROM THE SIDE, AND THE PLATES SEAT INTO THE SHAFT. YOU THEN TIGHTEN THE NUT AT THE TOP OF THE SHAFT AND COMPRESS THE SPRING. THIS TOOL IS ESSENTIAL.

Regards,

Mark

I thought (well at least on a w126), that there is a stop on the upper control arm.

Why is that?

(it worked fine for me, so i'm wondering why this would be a bad thing)

Because they were not designed for the MB. The AZ ones are known to bend.

Note that you have it backwards. Note that the base of the ball joint is pressed into the steering knuckle and note that the tapered stud is inserted in the lower control arm. Note that this arrangement is opposite that of most domestic vehicles and frequently causes confusion amongst those who have not noted the difference.

Oh Geez..many appologies...
 

I absolutely did have it "bass ackwards". Yes the ball joint sockets are pressed into the STEERING KNUCKLE, and the threaded spindle extends DOWNWARD THROUGH THE LCA. You know, the last time I did ball joints was about 5 years ago on my previous 300D. It amazes me lately how details that would once stick fresh in my my mind like glue for years, now seem to fade into a fog!!!! Oh to be in my twenties again!!!!

Thanks Tangofox007 for catching that!!!

Regards,

Mark

Upward, actually.

I thought this too. I am looking to replace my front shocks soon. If the shock is indeed what is holding the suspension then I will have the dealer do it. Thats just TOO scary for me to want to be a part of. :eek:

Can anyone confirm the actual process of front shock replacement?

How big of a press do you think lower ball joint would need? Would a 12 TON A-FRAME INDUSTRIAL HEAVY DUTY FLOOR PRESS do the job?

Absolutely right-I used the loan-a-tool to replace springs on an old Civic once-they started to bend just doing those little ones-they would not be strong enough to do Mercedes springs safely.

My lower control arm bushings are shot and I called the local indy who referred me to someone else. That guy didnt seem to want to do it and quoted me $1500.. is that normal or did he want me out of there? If thats what I can expect in California I'll just get the spring compressor myself.