DIY alignment procedure (with photos)
Thanks for the interest. This simple alignment approach saved me a lot of time, hassle, and some $$, as I have 4 earlier MBs (2 84 190Ds, 97 300D, and 99 SLK) with various DIY front end R/Rs completed.
Step 1) assemble required tools: 7ft. or 8 ft board, 2 ft. level, a pen, and masking tape (the masking tape is not essential, as you may mark directly onto your board, yet you will probably check distances several times when adjusting, and therefore the masking tape can be applied fresh for each measurement and this eliminates confusion)
(PLEASE SEE PHOTOS POSTED BELOW)
Step 2) drive the car onto level ground, and in doing so ensure that the car was driven directly straight ahead for at least 3 or 4 yds prior to parking. After parking do not adjust the steering wheel. Almost all cars will have some play in the steering paraphernalia, but the technological inclination of the wheels is to roll as straight as possible. Hence, we want to check the alignment after the wheels have rolled naturally for a distance.
Step 3) position the board, beginning with the front of the wheels. The center of the board as it lays on the ground should fall directly under the most forward center-point of the tire wall (approximately is OK). Place the level vertically on the center of the tire wall so as the bottom touches the end of the board. Slide the board one way or the other as required so as it is even with the level when the level is perfectly vertical.
Step 4) record the distance between the outside of the front of the wheels. Place a piece of masking tape on the board where it protrudes under the front wheel on the other side of the car, and position the level vertically above. Carefully mark a line on the masking tape with the pen.
Step 5) lay the board behind the front wheels and follow the same general format as in steps three and four, so as to record the distance between the outside of the rear of the wheels.
Step 6) compare the two marks recorded on the masking tape. If they are more than 1/8" in variation, then adjust the wheel positions by removing the front wheels loosening the tie rod assemblies, and turning them appropriately to bring the wheels to the point that they are both rolling in the same direction. This usually takes three or four adjustments and subsequent alignment checks to bring them perfectly aligned. Theoretically both L and R tie rod ends should be adjusted near to equal amounts, but an exception might be when a collision or impact on one wheel has skewed its individual alignment.
Step 7) check caster and camber - simply place the level vertically near the center of each wheel and thereby identify either wheel being far off level, and/or in substantial variance from one another. Depending on the wheels and tires you're dealing with, you may need to tape some spacer blocks onto the level to contact only with the tire walls top and bottom so as the protruding rim does not skew the level reading. In the photo, my stock 15 in. wheels on my 190D allow for the level to sit flush against the tires without any interference from the protruding rim
Important consideration:
If you're dealing with an earlier model car especially, it is best to check for play in both the suspension and steering components before being very concerned about achieving a precise alignment. Of course an exception might be if the car has been in a collision and the alignment is obviously a way off. Common points of wear as our Benz's age are the center drag links and the tie rod ends. these components are easily checked by rolling the front end of the car onto elevating ramps, and have an assistant sit in the car and turn the wheel back-and-forth slightly at a moderate rate. Erstwhile you should lie under the car and watch each connection in the steering assembly attentively, to identify where play (loose connections) prevail. The other common point of wear is the lower ball joints. To check these place a jack under the lower control arm close to the wheel, and elevate the respective side of the car. Take a long sturdy screwdriver or bar and pry between the lower control arm and wheel spindle assembly. If any play exists here, the ball joints require replacement.
