Elimination of vibrations from the front of the car (BMW 5 Series E39)

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

Examination

Check the tire pressure and adjust if necessary.

Perform a test drive. Determine as accurately as possible the limits of the malfunction: speed range, road conditions, driving on turns and in a straight line.

Raise the car.

Check the centering of the middle part of the rim. The wheel hub should protrude above the console of the disc wheel or at least end with it. Otherwise, replace the rim.

Check the wheel suspensions. To do this, check the rubber-metal bearings, joints, shock absorbers and rims for perfect condition.

Remove the wheels and clean them. Also remove any stones from the tread.

Check the tires for wear spots. These are areas with a slight tread depth that can occur as a result of the wheel locking up when braking.

Check the tread depth of individual tires and compare them with each other. If the tires are abnormally worn at the front and/or rear, it is necessary to determine the parameters of the vehicle's chassis at the front and rear and adjust them if necessary. In this case, the wheel alignment must be adjusted to the upper tolerance limit.

Please note: To determine the chassis parameters, appropriate measuring equipment is required, which is usually only available in a specialized workshop.

Perform a test drive and check if there are any other faults.

Checking the radial and lateral runout of wheels

With the vehicle raised, place the linear movement indicator first on the tread track and then on the sidewall of the tire. Turn the wheel slowly by hand and read the readings from the indicator scale. Mark the maximum radial runout on the tire with chalk.



Prescribed wheel runout values: maximum radial runout is 0.8mm; maximum lateral runout is 1.2 mm.

If these values are not maintained, balance the wheels on a stationary balancing machine. In this case, the wheels, as on a car, must be centered in the middle part. Conical clamping devices that center the wheel relative to the central hole are not allowed. The permissible residual imbalance in both balancing planes is 5 grams.

Elimination of radial runout

Release the air from the tire and press the tire bead against the base of the rim.

Rotate the tire on the rim by 120°.

Inflate the tire and check the radial runout again.

If the measured value exceeds the specified value, rotate the tyre on the rim by another 120° and check the radial runout,

If the prescribed maximum value is observed, perform wheel balancing.

Checking the radial and lateral runout of the rim

Center the rim without the tire in the middle part on the balancing machine or install it on the wheel hub. Perform measurements with a linear displacement indicator.



Check the radial runout in the "H" locations and the lateral runout in the "S" locations. In this case, local deviations in the dial indicator readings caused by elevations or depressions in the rim material are not taken into account.



Prescribed rim runout values: maximum radial runout is 0.3 mm; the maximum lateral runout is 0.3 mm.

If the measured runout values exceed the specified values, replace the rim.

Mounting wheels on a car

With the vehicle lifted, position the wheels so that the maximum radial runout is at the top. In this position, tighten the wheel bolts crosswise with a torque wrench to 100 Nm.

Note: If the difference in wear between individual tires is insignificant, install the wheels with the smallest radial runout and minimum imbalance on the front axle.

Perform a test drive. If vibrations still occur at the front of the vehicle or at the steering wheel, this may be due to residual imbalance, which can be corrected by subsequent balancing on the vehicle.

Subsequent balancing or equilibration of wheels on a car

When balancing the drive wheels, it is necessary to rotate both tires of one axle.

The wheels must be driven by the car's engine so that the wheels rotate synchronously. In cars with all-wheel drive, both axles must be lifted.

Take a test drive.

If the faults still occur, the radial or lateral runout of one or more tires is too large. This cannot be measured with workshop tools. In this case, the only option is to replace the front and/or rear tires. In this case, the tires must be replaced in pairs, i.e. for the entire axle at the same time.