Steering gets really sensitive at highway speeds. Hit a bump then car likes to shake left and right.
Sound like out of balance tire or a separated tire or bearing but, the two most common causes are the ones. I suggest visit some tire shop and would like to have the tires inspected and balanced.
Some customers may comment on shaking/vibration in the steering wheel, floor or seat while driving at highway speeds (typically between 60-72 mph (96-115 km/h)) on smooth roads.
These specific vehicles may be sensitive to various rotating mass assemblies, especially if they are considered to be out-of-balance.
In order to correct this:
1. Visually inspect the tires and the wheels. Inspect for evidence of the following conditions and correct as necessary.
- 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. 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.
4. 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.
5. After confirming wheel balance and wheel runout, if any changes were made, road test the vehicle again.
6. 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The screened tire program is no longer in effect for Bridgestone/Firestone, Goodyear and Michelin.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.
7. Replace both lower control arms on vehicles built prior to the VIN breakpoints shown. 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.
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Nov 18, 2011 |
1996 Geo Prizm