Diagnostic Information And Procedures; Abnormal Or Excessive Tire Wear; Trim Height - GMC chervolet camaro 1999 Service Manual

3-4 Suspension General Diagnosis
Diagnostic Information and Procedures
Abnormal or Excessive Tire Wear
Many conditions, including the following list, can cause
irregular or premature tire wear:
• Incorrect inflation pressure
• Lack of regular rotation
• Driving habits
• Improper tire and wheel alignment
If you reset tire and wheel alignment due to a tire
wear condition, always rest the toe as close to
O degrees as the specification allows.
Rotate the tires if you notice any of the following
conditions:
• Front and rear tire wear is unequal
• The tread of any tire wear is uneven
• Left and right front tire wear is unequal
Test the tire and wheel alignment if you notice any of
the following conditions:
• The left and the right front tire wear is unequal
• The tread of any front tire wear is uneven
• The front tire treads have a scuffed appearance
with feather edges on one side of the tread
ribs or blocks
Trim Height
Incorrect trim heights can produce symptoms similar
to those which produce tire and wheel misalignment.
Inspect trim heights whenever you diagnose
steering and vibration concerns.
In order to measure the trim heights accurately, use
the following check list:
• Tires should be at the correct pressure as shown
on the tire placard and up to vehicle capacity
• The fuel tank should be full
• The vehicle should have no additional weight or
passengers
• Seats should be in the full back position
• The rear compartment should be empty, except
for a spare tire and a jack, and a simulated
fuel load if required
• The vehicle should be on a known level floor
• Close all doors, the hood, and the rear
compartment lid
• Jounce the front and/or rear bumper of the vehicle
at least 38 mm (1.5 in). After jouncing, let the
vehicle settle. After recording the trim height
measurements desired, repeat the jounce
operation for a total of two times. Trim heights are
the average of the high and the low measurements
Measure all dimensions vertical to the ground. In order
to be considered correct, trim heights should be
within 1 O mm (0.4 in) of specification.
Suspension
Measuring Trim Height at Vehicle Side Rocker
Molding
349187
1. Calculate the trim heights (1 and 2) as measured
at the inner edge of the side rocker panels (3) to
the ground after each jounce/rebound cycle.
Record your measurement.
2. Verify the trim height measurements. Refer to
Trim Height Specifications.
3.
Continue to measure the vehicle trim heights at
the front and at the rear fascia at locations shown.
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