Eliminating vibration from the front of the car (BMW 7 Series E32)

Vibration of the steering wheel at certain speeds usually indicates an imbalance of the wheels.

Examination

Check your tire pressure and adjust it if necessary.

Take a test drive and determine as accurately as possible the conditions under which the malfunction occurred: speed range, type of road surface, driving on a turn or in a straight line.

Raise and support the vehicle.

Check the alignment of the discs. The wheel hub should protrude above the edges of the disc or be flush with them. If this is not the case, replace the discs.

Check the wheel suspension, for which check the condition of the rubber-metal hinges, joints, shock absorbers and springs.

Remove the wheels and clean them, remembering to remove any stones from the tire tread.

Check for skid marks on your tires, which are areas of shallow tread depth that result from braking with locked wheels.

Measure the tread depth of individual tires and compare the results. If the tires are abnormally worn at the front and/or rear, measure the toe-in at the front and rear and make adjustments if necessary. The toe-in adjustment should ensure the upper limit of the permissible values.

Note: For measurements, it is better to contact a workshop that has the necessary equipment.

Take the vehicle for a test drive and check if the problem still exists.

Checking the lateral runout and the height runout of the wheels

On the raised vehicle, install the dial indicator on the working surface and on the sidewall of the tire. Turn the wheel slowly by hand. Determine the runout by the dial indicator arrow and mark the maximum runout height with chalk. The maximum runout height is 0.8 mm, the maximum lateral runout is 1.2 mm.



If these values are not achieved, balance the wheels on a special installation. In this case, the wheels must be centered in the same way as on the car. Conical clamping devices for centering the wheel in the central hole are not allowed. The permissible imbalance in both planes is no more than 5 g.

Elimination of height runout

Release air from the tire and press the tire lugs into the base of the rim.

Rotate the tire on the rim by 120°.

Inflate the wheel and check the height runout again.

If the maximum runout value is exceeded, rotate the tire again 120° on the rim and check the height runout again. If the desired value is reached, balance the wheel.

Checking the lateral runout and the runout by the height of the disc

Center the disk without the tire on a balancing machine or on the car. Install a dial indicator.

Measure the height runout (H) and lateral runout (S) on the disc. Height Runout (disc deviation from circumference) is measured on the disk landing shelf, and the lateral runout is measured on the side surface of the disk edge. In this case, you can ignore random jumps of the indicator arrow, which are caused by small protrusions or depressions.

Maximum height runout - 0.3 mm; maximum lateral runout - 0.3 mm.



If the specified values are exceeded, replace the disk.

Installing wheels on a car

On the raised vehicle, install the wheels so that the place with the maximum runout in height is at the top. In this position, tighten the wheel bolts crosswise with a torque of 100 Nm.

Note: If the difference in wear between individual tires is small, then the wheels with the minimum height runout and minimum balance weights should be installed.

Take a test drive. If the vibration of the front of the car and the steering wheel is still there, then we can talk about residual imbalance, which is eliminated by balancing on the car.

Wheel balancing on a car

When balancing the drive wheels, place both wheels of the same axle on a roller stand.

The wheels must be driven by the car's engine so that the wheels rotate synchronously.

Take a test drive.

If there are defects, this means that the radial movements or runouts of one or more tires are too large. It is impossible to measure them using workshop equipment. In this case, the only option is to replace the front and/or rear tires. In this case, tires should only be replaced in pairs.