Inspection Of The Toe-In
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. Western Star dealers must have proof of this calibration history.
- Apply the parking brakes and chock the rear tires.
- Raise the front of the vehicle until the tires clear the ground. Place safety stands under the axle.
- Using spray paint or a piece of chalk, mark the entire center rib of each front tire.
- 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.
- Place a turn-plate or turntable under each front tire. Remove the safety stands from under the axle, then lower the vehicle. Remove the lock-pins from the gauges; make sure the tires are exactly straight ahead.
- 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 Fig. Lock in place. Check
that the scale is set on zero.
Note: B minus A equals toe-in.
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Distance at front of tires.
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Distance at rear of tires.
Fig. 1, Wheel Toe-In (overhead view)
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- Place the trammel bar at the front of the tires, as shown
in Fig. and adjust the scale end so
that the pointers line up with the scribe lines. See Fig.
Fig. 2, Trammel Bar Positioning
Fig. 3, Setting Trammel Bar Pointers
- Read the toe-in from the scale. Toe-in should be in the range of -1/32 to +3/32 inch. If corrections are needed, take the vehicle to your Western Star Dealer to adjust the toe-in. The Toe-in should be set as close as possible to +1/32 inch.
Note: If turn-plates or turntables are not available, lower the vehicle. Remove the chocks from the rear tires and release the parking brakes. Move the vehicle backward and then forward about six feet (two meters).