DeVille DTS V8-4.6L VIN 9 (2002)
3.
Road test the vehicle with the Electronic Vibration Analyzer (EVA) essential tool for a sufficient distance on a known, smooth road surface to
duplicate the condition. Record the Hertz (Hz) reading as displayed by the EVA onto the tire data worksheet shown. This should be done after a
tire break-in period of at least 10 miles (16 km) at 45 mph (72 km/h) or greater, in order to eliminate any possible tire flat-spotting.
4.
If the road test indicates a shake/vibration still exists, check the imbalance of each tire/wheel assembly on a known, calibrated, off-car dynamic
balancer. If any assembly calls for more than 1/4 ounce on either rim flange, remove all balance weights and rebalance to as close to zero as
possible.
Important:
Some GM dealers may have a Hunter GSP9700 Road Force Balancer. This will simplify Step 5 by not requiring dial indicators. If a Hunter
GSP9700 machine is available, it may also be used to measure the radial force of the tire/wheel assembly. A guideline here is 18 lbs or less.
5.
While on the balancer, measure wheel runout. If radial or lateral runout exceeds .020 in (0.50 mm) for aluminum wheels (.030 in (0.76 mm) for
steel wheels), replace the wheel.
6.
After confirming wheel balance and wheel runout, if any changes were made, road test the vehicle again.
7.
If the smooth road shake/vibration still exists:
Important:
The completed worksheet must be attached to the hard copy of the repair order.
^
Record Radial Force Variation readings if you have access to Hunter GSP9700 Wheel Balance equipment. Use the worksheet shown in
this bulletin to record the readings.
^
If one or more of the tires have RFV readings in excess of 18 lbs, match mount the tires to get below 18 lbs. Readings of 12 lbs. or less are
preferable for critical customer concerns.
^
If the RFV can not be reduced to an acceptable level, replace the affected tire with one obtained locally.
^
The screened tire program is no longer in effect for Bridgestone/Firestone, Goodyear and Michelin. Low speed screened tires are available
from Continental General only, and only for the Buick LeSabre.
^
Road test the vehicle to ensure the shake/vibration has been resolved.
8.
Replace both lower control arms on vehicles built prior to the VIN breakpoints shown. On Aurora, Bonneville, DeVille, Park Avenue, Park
Avenue Ultra and Seville models, a newly developed hydro-bushing lower control arm with improved damping characteristics has been released.
This control arm is not used on the LeSabre. The new lower control arms may provide an incremental improvement to the vehicle ride. Customers
who have become "tuned in" to the shake condition may still feel some shake in the vehicle after the new lower control arms are installed. Refer to
Lower Control Arm Replacement, (refer to the Parts Information table below for SI document ID numbers).
Important:
THE CONTROL ARMS SHOULD ONLY BE INSTALLED ON VEHICLES IF, AFTER THE TIRE AND WHEEL DIAGNOSIS AND
REPAIRS HAVE BEEN PERFORMED, THE VIBRATION CONDITION STILL EXISTS.