MAHLE RTI Laser 4 - Manual (Page 5)

Page 4
PRE-ALIGNMENT CHECKS
To maintain a true alignment job; ensure maximum tire mileage and steering safety, it is important to perform
certain pre-alignment checks before doing wheel alignment adjustments. They are:
1. Inflate tires to proper inflation pressures.
2. Check car spring height.
3. Check shock absorbers and struts.
4. Inspect steering/suspension parts for wear or looseness. Replace
parts which are worn beyond manufacturer’s accepted tolerances.
5. Check calibrations of the Laser 4 wheel alignment equipment. See
Calibration Procedure section of this manual.
FRONT WHEEL SETBACK
Front wheel setback is a condition in which
one front wheel has been driven or pushed
back, out of alignment, from the opposite
wheel. It is caused by one wheel of the vehicle
striking a curb or pothole in the road forcing
that wheel back from the other (See Fig. A).
To measure front wheel setback with the Laser
4 wheel alignment system, adjust front wheel
toe; center steering wheel, and note the
location of the Laser beam on the wheel
setback scale (See Fig. B) of the passenger side
laser toe gauge. Make sure that the Laser toe
gauges are centered on the wheel clamps. The
scale reads either right or left wheel setback.
The front wheel suspension should be adjusted
if the setback is greater than 1/4 inch.
Excessive front wheel setback will cause a
change in caster.
The Laser 4 alignment system automatically
compensates for front wheel setback because
of the use of the tapered, precisely ground
magnets. When toe is adjusted to zero, the tube
of the optical toe gauges become parallel to
each other. Front wheel toe reading is
unaffected by front wheel setback.