Subject : Shake/Vibration in steering wheel, Floor, Seat at Highway Speeds on Smooth Roads (Diagnose/Balance Tires/Wheels)
Models : 1998-2005 Buick Park Avenue, Park Avenue Ultra
2000-2005 Buick LeSabre
1998-2004 Cadillac Seville (SLS, STS)
2000-2005 Cadillac DeVille (DTS only)
2001-2003 Oldsmobile Aurora
2000-2005 Pontiac Bonneville (17″ Tires only)
Condition A few consumers might comment on shaking/vibration in the steering wheel, floor or seat at the same time as driving at highway speeds (most often between 60-72 mph (ninety six-a hundred and fifteen km/h)) on smooth roads. Those specific cars could also be delicate to quite a lot of rotating mass assemblies, particularly if they’re regarded as to be out-of-balance.
Correction
1. Visually check up on the tires and the wheels. Check up on for evidence of the next prerequisites and proper as important: • Missing balance weights • Bent rim flange • Irregular tire wear • Incomplete bead seating • Tire irregularities • Mud/ice build-up in wheel • Stones in the tire tread.
2. Set the tire pressure to 30 psi (205 kPa) COLD.
3. Street test the vehicle with the Electronic Vibration Analyzer (EVA) crucial instrument for a sufficient distance on a identified, smooth road floor to replicate the condition. Record the Hertz (Hz) reading as displayed via the EVA onto the tire knowledge worksheet found on the finish of this bulletin. This will have to be done after a tire break-in period of a minimum of 10 miles (sixteen km) at 45 mph (72 km/h) or greater, to be able to eliminate any conceivable tire flat-spotting.
4. If the road test indicates a shake/vibration nonetheless exists, check the imbalance of each tire/wheel assembly on a identified, calibrated, off-automobile dynamic balancer. If any meeting calls for more than ¼ ounce on both rim flange, take away all stability weights and rebalance to as with regards to 0 as possible. Vital: A few GM dealers will have a Hunter GSP9700 Highway Force Balancer, or a Coats XR1850 Runout Balancer. Both will simplify Step five by no longer requiring dial indicators. If a Hunter GSP9700 gadget is to be had, it can be used to measure the radial pressure of the tire/wheel assembly. A guideline right here is eighteen lbs or less.
5. While on the balancer, degree wheel runout. If radial or lateral runout exceeds .020 in (0.50 mm) for aluminum wheels (.030 in (0.seventy six mm) for metal wheels), change the wheel.
6. After confirming wheel stability and wheel runout, if any adjustments were made, street take a look at the vehicle again.
7. If the smooth highway shake/vibration nonetheless exists:
• If a Hunter GSP9700 Road Force/Balancing machine is used, document radial pressure adaptation (RFV) at the worksheet on the finish of this bulletin. If a number of of the tire/wheel assemblies read greater than 18 lbs, match mount the tire to the wheel to get under 18 lbs. Readings of 12 lbs or less are prime for delicate customers.
• If a Coats XR1850 Runout/Balancing Machine is used, document radial runout of the tire/wheel assemblies on the worksheet on the end of this bulletin. If one or more of the tire/wheel assemblies are greater than .040, fit mount the tire to the wheel to get underneath .040. Readings of .030 inch or less are finest for sensitive customers.
• If the RFV or runout can’t be reduced to a suitable degree, substitute the affected tire(s) underneath the guidelines of the GM Tire Warranty.
• The screened tire program is best to be had for the Normal branded tires used on the Buick LeSabre. Whole the tire request form at the finish of this bulletin and fax to Continental/General.
• Highway take a look at the car to verify the shake/vibration has been eliminated.
8. Exchange both lower keep watch over hands on vehicles built previous to the following VIN breakpoints. On Aurora, Bonneville, DeVille, Park Street, Park Avenue Ultra and Seville fashions, a newly advanced hydro-bushing lower regulate arm with improved damping features has been released. This regulate arm is not used at the LeSabre. The new decrease regulate palms may provide an incremental growth to the car ride. Consumers who have grow to be “tuned in” to the shake condition would possibly nonetheless really feel a few shake within the car after the brand new decrease keep watch over hands are installed. Refer to Lower Regulate Arm Substitute in SI.
