27
TWO-WHEEL CENTERLINE ALIGNMENT
(TR-12)
The purpose of a Two-wheel Centerline alignment is to align the front wheels to the theoretical
centerline of the vehicle. This is accomplished by adjusting the front wheels to match up with the
centerline of the vehicle.
Note
: the Two-wheel Centerline procedure is the first step of the Thrust
Angle and Four-wheel alignments.
The following should be completed before making any measurements or adjustments:
x
Equipment should be checked for calibration
x
The full weight of the vehicle must be on its wheels
x
The suspension must be inspected
x
Front and rear wheel clamps must be installed
x
Runout must be completed on the front wheel clamps
x
Adjustments for caster, camber, and SAI should have already been completed
Note:
Make sure that the steering box is in the center position and locked before loosening the
tie rods.
Two-wheel centerline alignment procedure:
1)
Lock steering box in the center position. You may use the TR-32 Steering Wheel Holder to
do this.
2)
Hang TR-38 and TR-39 Combi gauges on the rear wheels, with the Centering scale facing
towards the front of the vehicle. Set the toe dials to zero.
3)
Hang the TR-36 and TR-37 Laser Guns on the front of the vehicle and level them; The
Laser Guns should snap into place with the laser box facing the rear of the vehicle.
4)
Set the toe dials on the TR-36, TR-37, TR-38 and TR-39 to zero.
5)
Adjust the cross laser on the TR-37 to hit the mirror on the TR-36 laser gun. Adjust the toe
dial on the TR-36 until the cross toe laser beam drops back into the hole on the TR-37 laser
gun.
6)
Read the toe dial remembering that the Total Toe is half of what is on the Toe Dial.
7)
Adjust both toe dials to reflect the Total Front Toe Reading. You now have two parallel
laser beams going down the sides of the vehicle.
8)
Set the toe dials on the TR-36 & 37 laser guns to reflect the current toe condition, for
example 1/16” toe in.
9)
Notice the laser beams on the combi gauges, the idea here is to have both laser beams on
the same numbers on both combi gauges.
10)
To make adjustments for Front Toe you may set the toe dials equally for Total Front Toe.
For example if the desired toe is 1/8” out, set both toe dials to 1/8” toe out.
11)
With the steering box locked in the center position loose the tie rods and adjust one tie rod
HALF the distance back to the hole on the TR-37 laser gun, then adjust the other tie rod the
other HALF distance back into the hole on the TR-37 laser gun.
12)
Note the laser beams on the combi gauges, if the left gauge reads 7 and the right gauge
reads 5. The number for centerline would be 6 (7+5=12 divided by 2 = 6).
13)
Adjust BOTH tie rods evenly to make the numbers match and the cross toe laser is still in
the hole. The Two-wheel Centerline alignment is complete when the cross-toe laser is
reflected off the cross-toe mirror back into the hole and the numbers on the Centering
scales match.
