Toe-In Inspection
For vehicle alignment to be accurate, the shop floor
must be level in every direction. The turn plates for
the front wheels must rotate freely without friction,
and the alignment equipment must be calibrated
every three months by a qualified technician from the
equipment manufacturer. Freightliner dealers must
have proof of this calibration history.
1.
Apply the parking brakes and chock the rear
tires.
2.
Raise the front of the vehicle until the tires clear
the ground. Place safety stands under the axle.
3.
Using spray paint or a piece of chalk, mark the
entire center rib of each front tire.
4.
Place a scribe or pointed instrument against the
marked center rib of each tire, and turn the tires.
The scribe must be held firmly in place so that a
single straight line is scribed all the way around
each front tire.
5.
Place a turn-plate or turntable under both front
tires. Remove the safety stands and lower the
vehicle. Remove the lock-pins from the gauges;
make sure the tires are exactly straight ahead.
NOTE: If turn-plates or turntables are not avail-
able, lower the vehicle. Remove the chocks
from the rear tires and release the parking
brakes. Move the vehicle backward, then for-
ward about six feet (two meters).
6.
Place a trammel bar at the rear of the front tires;
locate the trammel pointers at spindle height,
and adjust the pointers to line up with the scribe
lines on the center ribs of the front tires. See
. Lock in place. Check that the scale is set
on zero.
7.
Place the trammel bar at the front of the tires
(see
) and adjust the scale end so that
the pointers line up with the scribe lines. See
8.
Read the toe-in from the scale, and compare it to
the toe-in specification in
Group 33
of the ve-
hicle Workshop Manual. If corrections are
needed, refer to
Group 33
of the vehicle Work-
shop Manual for instructions on adjusting the
toe-in.
33–07 Steer Axle Hub Cap Vent
Plug Inspection
General Information
As a function of their design, hubcap vent plugs will
on occasion exhibit signs of hub oil on their exterior
surface. Depending on environmental conditions
and/or age of the plug, the amount of oil present can
vary. This is a normal result of the venting process
due to pressure increase within the hub cavity. For
an example of normal vent plug appearance, see
A vent plug can wear or be damaged and cause ex-
cessive leakage, or allow water to enter the hub and
contaminate the oil. For examples of a leaking vent
plug, see
and
. Evidence of a leaking
vent plug may appear as;
f330082a
10/05/2016
A
B
NOTE: B minus A equals toe-in.
Fig. 9, Wheel Toe-In (overhead view)
f330014a
10/05/2016
Fig. 10, Trammel Bar Positioning
Front Axle
33
Business Class M2 Maintenance Manual, November 2016
33/6
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