JOSAM laser AM
Measuring system
38
Centering of the steering box
Checking the center point of the steering box
when it is marked.
Hang the frame gauges, gauge extensions and
measuring scales.
Jack up the axle.
Attach the wheel adapter and laser projector.
Run-out of the wheel can be compensated with the
adjustment knobs on the adapter.
Manufacturers mark the center point on the
steering box and the input shaft, as well as the
maximum deviation between the mark on the input
axle and the mark on the steering box.
Maximum deviation is no 10
°
.
Turn the steering wheel until the mark on the
steering box is in the designated center point.
Aim the laser projector from the wheel that is on
the same side as the steering box is located,
toward the front measuring scale A and read the
value. Rotate the laser projector and aim it at the
rear measuring scale B and read the value.
If the values are the same on both measuring
scales, the center point of the steering box is in
agreement with the straight ahead position of the
wheels.
If the values on the measuring scales A and B do
not agree, check the deviation.
The normal deviation between the middle position
of the steering box and the straight ahead position
is 1
°
per meter, 1
°
= 17. 5 mm per m.
The difference between the values on the front and
rear measuring scales is given in millimeters (mm).
The distance between the measuring scales is in
meters (m).
The value in (mm) divided by the distance between
the measuring scale in (m), gives mm/m.
For example:
The front measuring scale A = 115
Rear measuring scale B = 220
The distance between the measuring scales A and
B = 6m
220 – 115 = 105 : 6 = 17.5
The deviation is 17.5 mm/m, or 1
°
per meter.
If the deviation is more than 1
°
/m, the length of the
steering linkage should be adjusted so that the
center point on the steering box corresponds with
the straight ahead position of the wheel.
