For 1990-2009 cars

Rotors and drums do not have a set tolerance. However, rotors or drums with more than 21 g (0.75 ounce) imbalance have the potential to cause vibration. Inspect the rotors and the drums for imbalance using either the on-vehicle or the off-vehicle method.

### Checking Rotor/Drum Imbalance (On-Vehicle)

1. Raise and suitable support the vehicle. Refer to Lifting and Jacking the Vehicle in Vibration Diagnosis and Correction.
2. Remove the tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation in Tire and Wheel.

Caution: One or more of the following guidelines may apply when performing specific required tests in the work stall:

• | When a test requires spinning the drive wheels with the vehicle jacked up, adhere to the following precautions:

- | Do not exceed 56 km/h (35 mph) when spinning one drive wheel with the other drive wheel stopped. This limit is necessary because the speedometer indicates only one-half the actual vehicle speed under these conditions. Personal injury may result from excessive wheel spinning.

- | If all of the drive wheels are spinning at the same speed, do not exceed 112 km/h (70 mph). Personal injury may result from excessive wheel spinning.

- | All persons should stay clear of the rotating components and the balance weight areas in order to avoid possible personal injury.

- | When running an engine in the repair stall for an extended period of time, use care not to overheat the engine and the transmission.

• | When a test requires jacking up the vehicle and running with the wheels and brake rotors removed, adhere to the following precautions:

- | Support the suspension at normal ride height.

- | Do not apply the brake with the brake rotors removed.

- | Do not place the transmission in PARK with the drive axles spinning.

- | Turn Off the ignition in order to stop the powertrain components from spinning.

• | When running an engine in the work stall, use the exhaust removal system to prevent breathing dangerous gases.

3. Reinstall the wheel nuts in order to retain the rotors/drums.
4. Run the vehicle at the complaint speed while inspecting for the vibration.
5. If the vibration still exists, perform the following steps:

5.1. | Remove the rotors/drums.

5.2. | Run the vehicle back to speed.

6. If the vibration is eliminated, perform the following steps:

6.1. | Remove the rotors/drums one at a time.

6.2. | Perform the vibration test for each rotor/drum.

6.3. | Replace the rotor/drum that is causing the imbalance.

6.4. | Inspect the balance of the new rotor/drum.

### Checking Rotor/Drum Imbalance (Off-Vehicle)

1. Measure the diameter and the width of the rotor/drum.
2. Mount the rotor/drum on a balancer in the same manner as a wheel.

Important: You can only inspect the rotors/drums for static imbalance. Ignore the dynamic imbalance reading.

3. Inspect for static imbalance.
4. If the rotor/drum shows imbalance, replace the rotor/drum.
5. Inspect the balance of the new rotor/drum before you install the rotor/drum on the vehicle.