[200q20v] DIY Alignment, tools and procedures

Bernie Benz b.m.benz at prodigy.net
Tue Jun 5 23:54:58 EDT 2001


Required speciality tools and surface area.

1.  5' straight edge.
2.  Carpenter's framing square.
3.  Level, 9" torpedo, carpenter's, ect.
4.  Plumb bob.
5.  Chalk or floor marking pencil.
6.  Steel tape measure.
7.  2 Slip plates. = 1'sq. floor tiles, greased, face to face.
8.  Floor jack.
9.  A relatively flat garage floor or driveway, doesn't have to be perfect.


Calibrate your level.

1.  On bench top, shim under level until bubble is centered.  Rotate level
end for end, 180d.  Bubble must remain centered, if not adjust vial or get
another level.
2.  Shim under one end until full bubble moves just outside of mark on vial.
Measure shim height, h, required for this bubble movement, and length, l, of
level.  h/l = tan <, where < = the one bubble angle of your level.  Look up
< in your trig tables.  Write this angle on your now calibrated level.

Calibrate your alignment platform, floor.

1.  Mark off the four tire contact patch areas upon which you intend to
perform the alignment.  With two equal thickness blocks, one block on  each
of the two front contact patches, and using your straight edge, check the
floor level across these front contact patches, and record results.
Example: 1/4 bubble high on right side.
2.  Repeat for rear contact patches.

Insure that all relevant adjustment points are adjustable, not frozen.
Check all suspension and steering joints and bushings for obvious looseness
or failures.
Inspect each wheel rim and tire sidewall for runout by jacking suspension
and spinning wheel.  Mark high and low points of/on tire sidewall, and
difference.  (The sidewall, not the rim, is the easier alignment reference,
as used in this procedure.)

ALIGNMENT: To be done in order.  Camber and caster affect toe, therefore toe
must be the final adjustment.

CAMBER: Front and Rear.

My usual specs in general are within the broad factory spec range, depending
upon the useage.  Example:  200-20V front camber factory spec. -.5D +/- .5D.
For freeway cruising, what the 200 was built for and best at, I use 0.0D
camber for max tire life.  For aggressive driving I would use -0.5D (with a
prestressed Benz Strut Brace) at some sacrifice in tire wear.  For track (no
personal experience) I'd start with -1.0D, who cares about tire life?
Winning is everything!
But, IMO, the factory allowed side to side difference tolerences are grosely
unacceptable.  They should be zero, or as close to zero as possible.  DYI is
about the only way to achieve this with certainty.
1.  Drive car straight ahead onto the alignment platform.  If you found
significant sidewall runout, >1/8", position the tire on the patch such that
the high and low points are located front and back, not up and down.

2.  Hold the square vertically against the side wall just to one side of the
contact patch area (to avoid the sidewall bulge at the contact area) and
note the level reading on the horizontal arm of the square.  Correct your
bubble reading for floor level and convert it to degrees using your level
calibration factor.  This measured camber angle is negative if the top of
the wheel is leaning inward, positive if outward.  Repeat on the other side.

3.  Adjust camber on each side in the desired direction, and retest as many
times as is required.  Here you can use the slip plates to normalize the
suspension after jacking, or just roll the car off of, and back on to the
alignment spots.  You should end up with your desired nominal camber, and
with zero camber difference side to side.  If your readings are not
repeatable, your procedure is flawed and/or there is suspension or steering
play to be corrected.

TOE: Front and Rear.

Objectives:  The chassis should go down the road straight, therefore toe
should relate to a common chassis reference.  Consideration:  Applied
driving wheel torque, the most prevalent running condition, and the
resultant suspension deflections will increase toe-in slightly on all driven
wheels relative to your static measurements.
1.  Drive car straight ahead onto the alignment platform with steering wheel
centered.  If you found significant sidewall runout, >1/8", position the
tire on the patch such that the high and low points are located up and down,
not front and back.

2.  From a horizontal straight edge held across the wheel, at axle height,
and held against the sidewall on either side, drop and mark plumb bob points
on the floor as follows:  Immediately in front of the front wheels, and
immediately behind the rear wheels.  Also, from both front and rear wheels,
points adjacent to the center of the B post.  Further, measure the distance
from the straight edge to a point at the center of the B post on the welded
joint to the door sill bottom rail.  These measurement points each side on
the B post welds are the common chassis reference points for both front and
rear wheel toe alignment.

3.  Total toe for an axle is determined by comparing the side to side
distances between like plumb bob points for that axle.  For instance, if the
distance between the points ahead of the front axle is shorter than the
distance between front axle points at the B piller, that difference is front
wheel total toe-in for the longnitudinal distance between points.  This
technique yields extreme accuracy because of this approx. 5' longnitudinal
distance between measurement points, rather than using measurements between
wheel rims.

4.  To reference the total toe to the chassis, each side must also be set
such that the measured distances from the tire side wall line to the B
piller reference points are equal, side to side, for that axle.  This being
done for both the front and rear axles.

5.  Road test.  If the steering wheel is not straight, decrease toe
adjustment on one side and increase by the same amount on the other.
Recheck front total toe and chassis reference measurements.

CASTER: Front 

With careful technique and solid suspension and steering, this method of
camber and toe measurement should yield a very consistant measurement
repeatability over short time and mileage periods, weeks to months, and
hundreds to thousands of miles.  Only with this proven repeatibility,
and if the car still pulls to one side, IMO, might Caster measurement and/or
adjustment be considered.  I have not, as yet, had to do so, but if need be
I would increase the caster on the side to which the car is pulling, and of
course recheck the toe thereafter.  

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