BMW Cars 1999-06

Shock Absorbers

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Removal & Installation





Click image to see an enlarged view

Fig. Rear suspension system-5 Series

  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following:

    Rear seat cushion and back rest
     
    Trim panel over the strut mount
     
    With the control arm supported, rubber cap and remove the nuts at the top of the strut mount
     
    Lower mounting bolt and lower the spring/shock assembly. Remove the assembly from the vehicle.
     

  4.  
  5. Use a spring compressor and compress the spring. Remove the top nut and pull the top mount off. Remove the spring.
  6.  

To install:

  1. Compress the new spring or replace the old spring on the shock. Install the mount and washers. Use a new locknut and tighten to 18 ft. lbs. (25 Nm). Release the spring.
  2.  
  3. Install the shock. Upper mount nuts: 16 ft. lbs. (21.5 Nm). Loosely install the lower mounting bolt.
  4.  
  5. With the vehicle lowered to the ground and at standard riding height, tighten the lower mount to 94 ft. lbs. (130 Nm).
  6.  
  7. Install the trim and seat cushions.
  8.  


    Click image to see an enlarged view

    Fig. Exploded view of the shock and coil spring assembly-5 and 7 Series


  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following:

    Rear seat cushion and back rest
     
    Trim panel over the strut mount
     

  4.  


NOTE
The coil spring, shock absorber assembly acts as a strap so the control arm should always be supported.



Low pressure switch electrical connection and turn on the ignition
 
Control rod nut, holding the collar with an 8mm wrench against torque. Don't disconnect the rod at the ball joint.
 

  1. Operate the lever on the control switch in the "discharge" direction for about 20 seconds to discharge fluid from the lines.

    Hydraulic line on the strut and turn off the ignition
     
    With the control arm supported, rubber cap and remove the nuts at the top of the strut mount
     
    Lower mounting bolt and lower the spring strut assembly. Remove the assembly from the vehicle.
     

  2.  
  3. Use a spring compressor and compress the spring. Remove the top nut and pull the top mount off. Remove the spring.
  4.  

To install:

  1. Compress the new spring or replace the old spring on the strut. Install the mount and washers. Use a new locknut and tighten to 18 ft. lbs. (25 Nm). Release the spring.
  2.  
  3. Install or connect the following:

    Spring strut. Upper mount nuts: 16 ft. lbs. (21.5 Nm). Loosely install the lower mounting bolt.
     
    Hydraulic line on the strut
     
    Control rod nut, holding the collar with an 8mm wrench against torque
     
    Low pressure switch electrical connection
     

  4.  
  5. With the vehicle lowered to the ground and at standard riding height, tighten the lower mount to 94 ft. lbs. (130 Nm).
  6.  
  7. Install the trim and seat cushions.
  8.  



Click image to see an enlarged view

Fig. Rear suspension system-5 Series

  1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
  2.  
  3. Remove or disconnect the following:

    Rear seat cushion and back rest
     
    Trim panel over the strut mount
     
    With the control arm supported, rubber cap and remove the nuts at the top of the strut mount
     
    Lower mounting bolt and lower the spring/shock assembly. Remove the assembly from the vehicle.
     

  4.  
  5. Use a spring compressor and compress the spring. Remove the top nut and pull the top mount off. Remove the spring.
  6.  

To install:

  1. Compress the new spring or replace the old spring on the shock. Install the mount and washers. Use a new locknut and tighten to 18 ft. lbs. (25 Nm). Release the spring.
  2.  
  3. Install the shock. Upper mount nuts: 16 ft. lbs. (21.5 Nm). Loosely install the lower mounting bolt.
  4.  
  5. With the vehicle lowered to the ground and at standard riding height, tighten the lower mount to 94 ft. lbs. (130 Nm).
  6.  
  7. Install the trim and seat cushions.

    Click image to see an enlarged view

    Fig. Exploded view of the shock and coil spring assembly-5 and 7 Series

  8.  

  1. Before servicing the vehicle, refer to the precautions in the beginning of this section.
  2.  
  3. Remove or disconnect the following:
    NOTE
    The coil spring, shock absorber assembly acts as a strap so the control arm should always be supported.



    Rear seat cushion and back rest
     
    Trim panel over the strut mount
     



    Low pressure switch electrical connection and turn on the ignition
     
    Control rod nut, holding the collar with an 8mm wrench against torque. Don't disconnect the rod at the ball joint.
     

  4.  
  5. Operate the lever on the control switch in the "discharge" direction for about 20 seconds to discharge fluid from the lines.
  6.  
  7. Remove or disconnect the following:

    Hydraulic line on the strut and turn off the ignition
     
    With the control arm supported, rubber cap and remove the nuts at the top of the strut mount
     
    Lower mounting bolt and lower the spring strut assembly. Remove the assembly from the vehicle.
     

  8.  
  9. Use a spring compressor and compress the spring. Remove the top nut and pull the top mount off. Remove the spring.
  10.  

To install:

  1. Compress the new spring or replace the old spring on the strut. Install the mount and washers. Use a new locknut and tighten to 18 ft. lbs. (25 Nm). Release the spring.
  2.  
  3. Install or connect the following:

    Spring strut. Upper mount nuts: 16 ft. lbs. (21.5 Nm). Loosely install the lower mounting bolt.
     
    Hydraulic line on the strut
     
    Control rod nut, holding the collar with an 8mm wrench against torque
     
    Low pressure switch electrical connection
     

  4.  
  5. With the vehicle lowered to the ground and at standard riding height, tighten the lower mount to 94 ft. lbs. (130 Nm).
  6.  
  7. Install the trim and seat cushions.
  8.  



Click image to see an enlarged view

Fig. Rear suspension system

  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove the trunk trim panel to expose the upper shock mounts.
  4.  
  5. Support the trailing arm and remove the lower mounting bolt.
    WARNING
    The support must not be removed until the new shock absorber is installed, and the vehicle must not be raised since this could damage the halfshafts.

  6.  
  7. Remove the cap and remove the upper mounting nuts and remove the shock from the vehicle.
  8.  

To install:

  1. Place the shock into position with new seals fitted between the shock absorber and body. Renew the upper self-locking nuts: 11 ft. lbs. (15 Nm) for the Z3, 16 ft. lbs. (22 Nm) for all other 3-Series vehicles.
  2.  
  3. Install the trunk trim panel.
  4.  
  5. Install the lower shock mounting to the rear axle assembly. The thrust washer on the rubber mount must face the screw head.
  6.  
  7. With the vehicle resting at standard ride height, tighten the mounting bolt to 63 ft. lbs. (87 Nm), or to 94 ft. lbs. (130 Nm) if marked with 10.9, for the Z3, or to 74 ft. lbs. (100 Nm) for all other 3-Series models.

    Click image to see an enlarged view

    Fig. Support the trailing arm and remove the bolt (1)-3-Series



    Click image to see an enlarged view

    Fig. Upper mounting nut locations-3-Series

  8.  

E30 Models
  1. Remove the trunk trim panel to expose the upper shock mounts.
  2.  
  3. Raise the rear of the vehicle and support safely.
  4.  
  5. Support the lower control arm and remove the lower mounting bolt.
  6.  
  7. Remove the upper mounting nut and remove the shock from the vehicle.
  8.  

To install:

  1. Exchange or replace the upper shock mount and tighten the upper shock nut to 11 ft. lbs. (15 Nm).
  2.  
  3. Replace the gasket between the shock mount and the body. Install the shock and tighten the nuts to 11 ft. lbs. (15 Nm). Install the trunk panel.
  4.  
  5. Install the lower shock mounting bolt and lower the vehicle. With the vehicle resting at standard ride height, tighten the mounting bolt, if unmarked, to 57 ft. lbs. (77 Nm) or, if marked 10.9, tighten the bolt to 74 ft. lbs. (100 Nm).
  6.  

E36 Models
  1. Remove the trunk trim panel to expose the upper shock mounts.
  2.  
  3. Raise the rear of the vehicle and support safely.
  4.  
  5. Support the lower control arm and remove the lower shock mounting bolt.
  6.  
  7. Remove the upper mounting nut, then remove the shock from the vehicle.
  8.  



Click image to see an enlarged view

Fig. The lower shock mounting bolt threads into the rear bearing carrier



Click image to see an enlarged view

Fig. Pull back the trunk lining to access the upper shock mounting bolts



Click image to see an enlarged view

Fig. With the lower mounting bolt removed, remove the upper mounting bolts and the shock can be carefully lowered down and removed

To install:

  1. Exchange or replace the upper shock mount and tighten the upper shock nut to 11 ft. lbs. (15 Nm).
  2.  
  3. Replace the gasket between the shock mount and the body. Install the shock and tighten the nuts to 11 ft. lbs. (15 Nm). Install the trunk panel.
  4.  
  5. Install the lower shock mounting bolt and lower the vehicle. With the vehicle resting at standard ride height, tighten the mounting bolt to 57 ft. lbs. (77 Nm) or if marked 10.9, 74 ft. lbs. (100 Nm).
  6.  

Ride Level Height Control Suspension
  1. Raise and support the rear of the vehicle.
  2.  
  3. Remove the rear seat cushion and back rest. Remove the trim panel over the strut mount.
    NOTE
    The coil spring, shock absorber assembly acts as a strap so the control arm should always be supported.

  4.  
  5. Disconnect the low pressure switch electrical connection and turn on the ignition.
  6.  
  7. Disconnect the control rod nut, holding the collar with an 8mm wrench against torque. Don't disconnect the rod at the ball joint.
  8.  
  9. Operate the lever on the control switch in the "discharge" direction for about 20 seconds to discharge fluid from the lines.
  10.  
  11. Disconnect the hydraulic line on the strut and turn off the ignition.
  12.  
  13. Support the control arm, pull off rubber cap and remove the nuts at the top of the strut mount.
  14.  
  15. Remove the lower mounting bolt and lower the spring strut assembly. Remove the assembly from the vehicle.
  16.  
  17. Use a spring compressor and compress the spring. Remove the top nut and pull the top mount off. Remove the spring.
  18.  

To install:

  1. Compress the new spring or replace the old spring on the strut. Install the mount and washers. Use a new locknut and torque to 18 ft. lbs. (25 Nm). Release the spring.
  2.  
  3. Install the spring strut and torque the upper mount nuts to 16 ft. lbs. (21.5 Nm). Loosely install the lower mounting bolt.
  4.  
  5. Connect the hydraulic line on the strut.
  6.  
  7. Connect the control rod nut, holding the collar with an 8mm wrench against torque.
  8.  
  9. Connect the low pressure switch electrical connection.
  10.  
  11. With the vehicle lowered to the ground and at standard riding height, torque the lower mount to 94 ft. lbs. (130 Nm).
  12.  
  13. Install the trim and seat cushions.

    Click image to see an enlarged view

    Fig. Strut and coil assembly with ride level height control (exploded view)

  14.  

Standard Suspension
  1. Raise and support the rear of the vehicle.
  2.  
  3. Remove the rear seat cushion and back rest. Remove the trim panel over the strut mount.
  4.  
  5. Support the control arm, pull off rubber cap and remove the nuts at the top of the strut mount.
  6.  
  7. Remove the lower mounting bolt and lower the spring/shock assembly. Remove the assembly from the vehicle.
  8.  
  9. Use a spring compressor and compress the spring. Remove the top nut and pull the top mount off. Remove the spring.
  10.  

To install:

  1. Compress the new spring or replace the old spring on the shock. Install the mount and washers. Use a new locknut and torque to 18 ft. lbs. (25 Nm). Release the spring.
  2.  
  3. Install the shock and torque the upper mount nuts to 16 ft. lbs. (21.5 Nm). Loosely install the lower mounting bolt.
  4.  
  5. With the vehicle lowered to the ground and at standard riding height, torque the lower mount to 94 ft. lbs. (130 Nm).
  6.  
  7. Install the trim and seat cushions.

    Click image to see an enlarged view

    Fig. Shock and coil spring assembly (exploded view)

  8.  

Testing & Inspection



The purpose of the shock absorber is simply to limit the sudden motion of the spring during compression and rebound cycles. If the vehicle is not equipped with these motion dampers, the up and down motion would multiply until the vehicle was alternately trying to leap off the ground and to pound itself into the pavement.

Contrary to popular rumor, unless gas charged, the shocks do not affect the ride height of the vehicle. This is controlled by other suspension components such as springs and tires. Worn shock absorbers can affect handling; if the front of the vehicle is rising or falling excessively, the "footprint" of the tires changes on the pavement and steering is affected.

The simplest test of the shock absorber is simply push down on one corner of the unladen vehicle and release it. Observe the motion of the body as it is released. In most cases, it will come up beyond it original rest position, dip back below it and settle quickly to rest. This shows that the damper is controlling the spring action. Any tendency to excessive pitch (up-and-down) motion or failure to return to rest within 2-3 cycles is a sign of poor function within the shock absorber. Oil-filled shocks may have a light film of oil around the seal, resulting from normal breathing and air exchange. This should NOT be taken as a sign of failure, but any sign of thick or running oil definitely indicates failure. Gas filled shocks may also show some film at the shaft; if the gas has leaked out, the shock will have almost no resistance to motion.



Click image to see an enlarged view

Fig. When fluid is seeping out of the shock absorber, it's time to replace it

While each shock absorber can be replaced individually, it is recommended that they be changed as a pair (both front or both rear) to maintain equal response on both sides of the vehicle. Chances are quite good that if one has failed, its mate is weak also.


NOTE
When replacing shocks, always make sure they are a matched set, or for one shock, make sure it matches the shock not being replaced.

 
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