32 00... Diagnosis Of Power Steering Systems

Facts: 

Because of the complex mode of operation of power steering systems, customer complaints are often difficult to follow and to diagnose effectively. Consequently, individual components are frequently replaced without the actual cause having been identified and eliminated. In the Warranty department this is manifested in an increasing number of steering components being sent in which reveal no faults or defects when they are checked.

The Warranty department rejects and sends back at the dealer's expense steering components on which:

• damage resulting from the exertion of force is detected, e.g. when gripped in a vice.
• corrosion damage which can be detected from external influences, e.g. corrosion to racks as a result of leaking/damaged gaiters (stone impact/rodent bites).
• the gaiters or protective caps are missing.

Procedure: 

• Only roughly clean steering components which are to be sent back - do not steam-jet clean!
• Mount the seal plugs of the new part on all removed parts and return in the original packaging.

Fig 1: Protective caps, rack-and-pinion steering

Courtesy of BMW OF NORTH AMERICA, INC.

Protective caps, rack-and-pinion steering

Fig 2: Identifying Protective Caps, Rack-And-Pinion Power Steering

Courtesy of BMW OF NORTH AMERICA, INC.

Protective caps, rack-and-pinion power steering

Fig 3: Identifying Protective Caps, Ball-And-Nut Power Steering

Courtesy of BMW OF NORTH AMERICA, INC.

Protective caps, ball-and-nut power steering

• Leave the gaiters mounted on rack-and-pinion steering and rack-and pinion power steering systems.
  NOTE: To remove tie rods, release the gaiter clamping bands at the tie rod end only, push back the gaiters and remove the tie rods. Seal gaiters with steering protective caps of the new part and secure with adhesive tape.
• Traces of corrosion on the rack indicate gaiter leakage.

Fig 4: Identifying Traces Of Corrosion On Rack

Courtesy of BMW OF NORTH AMERICA, INC.

Traces of corrosion on rack

• Check both gaiters for leaks and damage caused by e.g. stone impact or rodent bites and if necessary notify the customer.
  IMPORTANT:

  Damage caused by rodent bites is difficult to detect. The bite marks are often very small and only one side. Leakage at only one gaiter will result in corrosion at both ends of the rack (expansion line).

• Avoid damage during removal.
• Before replacing individual components, carry out thorough diagnosis.