MAHLE RTI Laser 4 - Manual (Page 10)

Page 9
CASTER READING (Laser 4 Plus)
Caster: The backward or forward tilt of the ball joint or strut at the top
Caster is measured in degrees:
Spindle support arm straight up and down on the true vertical: Zero Caster
Spindle support arm is tilted forward at the top from true vertical: Negative Caster
Spindle support arm is tilted back at the top from true vertical: Positive Caster
A vehicle with Positive Caster is shown in Fig. 15.
Proceed with the following steps to read Caster:
1) With the Electronic Gauge mounted on the left
front wheel clamp, turn the left front wheel
outward at the front for a 20 degree reading on the
radius gauge. (See Fig. 16)
2) Turn the Electronic Gauge so it is level.
3) Set the selector to CASTER and press the switch to
ON. Press the Zero Button. (See Fig. 18)
4) Turn the wheel inward at the front for a 20 degree
reading on the radius gauge. (See Fig. 17) This is a
total swing of 40 degrees.
5) Turn the Electronic Gauge so it is level.
6) Read Caster on the Digital Readout Scale (A positive
1.0 is indicated in Fig.18). The numeric reading will
be preceded by a + or - to indicate positive or negative
Caster.
7) Repeat the above procedure on the right front wheel.