PeachParts Mercedes-Benz Forum - View Single Post - Need tip on changing upper control arm on W210

kwmccauley · #2 04-01-2007, 04:59 PM

My car is a 1999 diesel with Turbocharger. It should be similar to yours but not exactly the same.
Well, that control arm you mention was probably the most challenging part of the job, except perhaps for the upper control arm on the driver's side.
The bolt head for the upper control arm that goes thorugh the fender well is, as it sounds like you know at this point, 15mm. The nut on the other end is 16mm. Once you get access (see below), use an offset box wrench to hold that. Loosen using the 15mm bolt head.
Here is what I had to do to get access. I have some digital photos I could send to you if this explanation does not sound sufficiently detailed. On the passenger side, remove the air cleaner cover, filter element and air cleaner box (housing). The air box is a press fit into a large rubber grommet in the frame. After you remove the top and filter element, disconnect the hose at the front and the box should swing up and out of the way so you can see what you are doing to get to the front 15mm bolt head.
This next step seems really overwhelming at first look but just go slow and it is not too bad. It goes back really easily. The photo I took in advance definitely helped me with the reassembly.
To get to the rear 16mm nut, carefully remove the cover to the electronic control module box. Disconnect the connectors then remove the control modules (I have a good picture I can send you on this too). They slide out like index cards in a file box. Once the modules are out, loosen the four screws holding the control module housing upper section to the lower base. Swing the box upper half up and toward the front of the car. I then used some simple wooden shims to go between the lower housing and the rear of the front fender well. SLIGHTLY deflect the lower box front lip toward the rear of the car. Now you will be able to see the 16mm nut. Hold that and undo the bolt head from the front of the fender well. When you put in the new control arm, do not tighten this bolt and nut to the specificed torque value until the car is resting on its wheels. Obviously, it is not possible to start the car with all of the electronic modules hanging out. What I did was to lower the wheels on to a set of ramps once I had the suspension components reconnected.

Do you already have the driver's side complete? If not, I'll send some info on that as well.
Please send me your e-mail address if you want me to send some photos.
Hope all goes well!
Ken