BMW X3 (F25) Service & Repair Manual: Mechanical steering gear

BMW X3 (F25) Service & Repair Manual / Suspension / Mechanical steering gear

Notes on checking steering backlash on vehicles with rack-and- pinion steering

NOTE: The evaluation "steering backlash" is made usually when the front axle is raised, where the track rod is angled.

The force introduced via the track rod is divided into a horizontal force and a vertical force relieving the thrust member (1) against the spring (2).

The steering box is depressurized on account of no hydraulic assistance due to engine standstill and is thus not preloaded! The play created in this way is incorrectly referred to as steering backlash.

Suspension

3 = Rack

Solution:

1. Check the tie rod backlash only in loaded condition or in the design position.

2. Checking with front axle raised:

  • To evaluate the play of the steering gear, it is necessary to pressurize the steering gear via its servo system!
  • The combustion engine must be running during hydraulically or electrically assisted steering for this purpose

Desired state: The steering must be backlash-free in all components!

Notes on replacement of steering gear/steering column/steering shaft following accident damage

Steering gear facts: In the event of accidents or driving conditions similar to accidents, shock-like loads can cause different types of damage to steering boxes. When a steering box is externally undamaged, it is sometimes only possible to identify damage with great difficulty and with great effort. However, damage of this nature poses an unacceptable risk to the vehicle because it can result in failure of the steering system.

Due to the disproportionate amount of effort involved, it is generally not sensible to check thoroughly all the individual components of the steering box and as an alternative it is necessary to take into account other components which can be checked more easily.

Steering gear procedure:

The steering box must be replaced if one or more of the following points apply:

A. Visible or noticeable damage to the steering box

  • Version with electric steering box (EPS): Examine in particular the control unit with all plug connections for damage and hairline cracks.

B. Unacceptable torque increase and jamming when the steering box is turned from lock to lock (without hydraulic/electrical assistance)

C. Permissible tolerances exceeded during axle/wheel alignment (include alignment record with invoice/report if necessary)

D. Fire damage

E. Damage, permanent deformation or fractures to:

  • Wheel rims in the event of a negative result from the wheel alignment check
  • Spring struts, steering stubs, wheel carriers
  • Wishbones
  • Struts or trailing links or anti-roll bar with this function
  • Body-side screwing/attachment points for wheel guide/control components
  • Front axle support
  • Pitman arms
  • Track rods
  • Steering box fixtures
  • Steering Column

NOTE: If the steering box replacement work which is required for safety reasons is refused by the customer or an insurance company for cost reasons, a memorandum to that effect must be drawn up and countersigned by the party bearing the costs of the accident repair.

Facts on steering column and steering shaft: In the event of accidents or driving conditions similar to accidents, shock-like loads can cause different types of damage to the steering shafts and to the steering columns. In case no external damaged of the steering column and the steering shaft can be noticed, it is sometimes only possible to identify damage with great difficulty and with great effort.

Procedure for steering column and steering shaft:

The steering column and the steering shaft need to replaced if one or more of the following points apply:

  • Visible or noticeable damage, deformation or breakage of the steering column or the steering shaft
  • Damage, permanent deformation or breakage of the track rod
  • Unacceptable torque increase and jamming when the steering column is turned from limit position to limit position (without hydraulic/electrical support)
  • Permissible tolerances exceeded after wheel alignment (include alignment record with invoice/report if necessary)
  • Positive check for activated crash system of the mechanical steering column: If there is no visible damage to the steering column, the steering column needs to be checked for an activated crash system:
  1. Open steering column lock
  2. Pull steering wheel out towards the driver (towards the body) until the physical limit position is reached, but do not use excessive force
  3. Push steering wheel towards engine compartment (approx. 20-30 mm away from body) into the comfort position and lock.

    If no end stop is present when pulling out the steering column or if the gaiter of the steering column shroud is tensioned, the crash system was activated and the steering column needs to be renewed.

NOTE: If the replacement of the steering column/steering shaft work which is required for safety reasons is refused by the customer or an insurance company for cost reasons, a memorandum to that effect must be drawn up and countersigned by the party bearing the costs of the accident repair.

IMPORTANT: The vehicle's operating licence will be invalidated whenever the function of any of its safety components is compromised!

This guideline is binding for all accident repairs to BMW and MINI vehicles!

Replacing gaiter for steering box on left or right

IMPORTANT: The hydraulic steering gear must be replaced if the polished surface of the rack is damaged (e.g. by corrosion)!

Necessary preliminary tasks:

  • Remove UNDERBODY PROTECTION .
  • Remove TRACK ROD END.

Clean track rod.

Release band clamp (1) and EAR CLIP (3).

Detach gaiter (2) from track rod.

Installation note:

Clean rack and check surface for damage (e.g. by corrosion).

Clean track rod and apply grease to taper.

NOTE: This ensures that the gaiter is not rotated when the track rod is rotated.

Suspension

After installation:

  • Perform CHASSIS/WHEEL ALIGNMENT CHECK.
Electronic chassis alignment
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Steering gear with servo unit
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