BMW Coupes and Sedans 1970-1988 Repair Guide

Rear Shock/Strut Assembly

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See Figure 1



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Fig. Fig. 1: Exploded view of rear strut assembly

REMOVAL & INSTALLATION




CAUTION
MacPherson strut springs are under tremendous pressure and any attempt to remove them without proper tools could result in serious personal injury!

1600, 2000 and 2002 Models

See Figures 2 and 3

The shocks on these models are separate of the coil spring.

  1. Raise the car and support the control arms with jackstands.
  2.  
  3. Remove the lower shock retaining bolt.
  4.  
  5. Remove the trim over the wheel arch, if equipped, in the trunk compartment and disconnect the upper strut retaining nuts at the wheel arch and remove the assembly.
  6.  



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Fig. Fig. 2: 2002 rear shock mount accessed from the trunk compartment



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Fig. Fig. 3: Cut-away view of rear shock upper mount assembly

To install:
  1. Install the assembly back into position, using new gaskets between the shock and the wheel arch, and new self-locking nuts on top of the strut.
  2.  
  3. Tighten the shock-to-body nuts to 16-17 ft. lbs. (21-22 Nm), and lower bolt to 52-63 ft. lbs. (16-82 Nm).
  4.  
  5. Install ant trim panels in the trunk compartment, if removed earlier. Lower the vehicle.
  6.  

1970-80 6-Cylinder Models
  1. On the 2500, 2800, Bavaria and 3.0, remove the sleeve which surrounds the shock absorber and the auxiliary spring as well as: the rubber washer; large metal washer; spacer tube; and the fastening plate.
  2.  
  3. On other models, remove the support disc, auxiliary spring (which fits around the shock absorber piston rod), and the outer tube. Remove both upper and lower lines, and inspect them, replacing if necessary.
  4.  
  5. Install in reverse order. In case you are replacing a shock absorber which has failed prematurely (especially due to leakage), it may be possible to avoid the cost of replacing the unit located on the opposite side. BMW dealers and some other shops are equipped with equipment designed for testing the shocks. You might be able to remove both shocks and have the performance of a new shock compared with that of the apparently effective old shock. If testing proves the performance of a new shock and slightly used shock to be sufficiently similar, re-use is possible. However, it is dangerous to risk replacing the only one rear shock without machine testing!
  6.  

1981-83 6-Cylinder Models

  1. On 1981-82 733i, remove the rear seat and back rest..
  2.  
  3. Raise the car and support the control arms with jackstands.
  4.  


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

  1. Remove the lower shock retaining bolt.
  2.  
  3. Remove any trim needed to access the assembly and disconnect the upper strut retaining nuts at the wheel arch and remove the assembly. On 733i models , the retaining nut is accessed from the rear seat compartment.
  4.  
  5. Remove the shock assembly from the vehicle.
  6.  

To install:
  1. Install the shock assembly back into position, using new gaskets between the shock and the wheel arch, and new self-locking nuts on top of the strut.
  2.  
  3. Tighten the shock-to-body nuts to 16-17 ft. lbs. (21-22 Nm), spring retainer-to-wheel house nuts to 16-17 ft. lbs. (21-22 Nm), lower bolt to 90-103 ft. lbs. (117-134 Nm).
  4.  
  5. On 733i models, replace the gasket that goes between the top of the strut and the lower surface of the wheel well. Final torquing of the lower strut bolt should be done with the car in the normal riding position.
  6.  

3 Series Models

The shock in these vehicles is separate from the coil spring.

See Figures 4, 5 and 6

  1. Remove the trunk trim panel, if needed 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. If equipped with a rubber cap over the mount in the trunk compartment, remove it and place aside.
  8.  
  9. Remove the upper mounting nuts and remove the shock from the vehicle.
  10.  



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Fig. Fig. 4: Remove the rubber cap over the shock mount in the trunk compartment



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Fig. Fig. 5: Remove the retaining nuts from the sides of the shock



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Fig. Fig. 6: Remove the retaining bolt from the bottom of the shock

To install:
  1. Exchange or replace the upper shock mount and tighten the upper shock nut to 11 ft. lbs. (15 Nm).
  2.  
  3. Install the shock and tighten the retainer 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 63 ft. lbs. (87 Nm) or if marked grade 10.9 on the bolt head,tighten to 94 ft. lbs. (130 Nm).
  6.  

5, 6 and 7 Series Models
EXCEPT RIDE CONTROL

The shock and spring are combined into a strut assembly.

  1. Raise and support the rear of the vehicle.
  2.  
  3. Remove the rear seat cushion and backrest. Remove the trim panel over the strut mount.
  4.  
  5. Support the control arm and remove the nuts at the top of the strut mount.
  6.  
  7. Remove the 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, then pull the top mount off. Remove the spring.
  10.  

To install:
  1. Compress the spring and position on the strut assembly. Install the mount and washers. Use a new locknut and tighten to 18 ft. lbs. (25 Nm). Release the spring.
  2.  
  3. Install the spring strut and tighten 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, tighten the lower mount to 94 ft. lbs. (130 Nm).
  6.  
  7. Install the trim and seat cushions.
  8.  

1987-88 7 SERIES WITH RIDE CONTROL

The shock and coil spring are combined into a strut assembly.

  1. Raise the car and support the control arms with jackstands.
  2.  
  3. For models with ride control, proceed with the following;
    1. Pull off and bridge (electrically) the low pressure switch electrical connection and turn ON the ignition.
    2.  
    3. Disconnect the control rod nut, holding the collar with a wrench. Do not 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. Disconnect the hydraulic line on the shock absorber.
    8.  

  4.  
  5. Remove the lower shock retaining bolt.
  6.  
  7. 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 spring and position on the strut assembly. Install the mount and washers. Use a new locknut and tighten to 18 ft. lbs. (25 Nm). Release the spring.
  2.  
  3. Install the assembly back into position on the vehicle, using new gaskets between the unit and the wheel arch, and new self-locking nuts on top of the strut.
  4.  
  5. Tighten the shock-to-body nuts to 16-17 ft. lbs. (21-22 Nm), lower bolt to 90-103 ft. lbs. (117-134 Nm).
  6.  
  7. Replace the gasket that goes between the top of the strut and the lower surface of the wheel well.
  8.  
  9. Final torquing of the lower strut bolt should be done with the car in the normal riding position.
  10.  

TESTING



The shock absorbers should be checked on a regular basis. Visual inspection for leaking oil and damage is a primary indicator of worn or broken shocks. A quick glance at the shocks will provide advance warning of shocks in need of replacement. If oil is visible in any amount more than a very slight coating, the shock need to be replaced. If any visible physical damage is noted, the shock should also be replaced.

The old time method of checking shocks by bouncing the corner of the vehicle is being outmoded by the use of gas pressure and deflecting disk technology shock absorbers. By the time the vehicle does bounce more than once during this type of test, the shocks have been in need of replacement for a long time. A gradual reduction in the handling capacity may not be noticed as it occurs over a long period of time. Some manufactures of shock absorbers use a design called deflecting disk. This design is inherently self-adjusting for wear and use. An indicator of worn shocks is uneven tire wear and a lack of suspension dampening while traveling over rough roads.

The shocks should always be replaced in pairs. It is also recommended to replace the springs on high mileage vehicles to restore original handling characteristics. Replace the shock mounts and rubber bushings. Check the condition of the stabilizer bar and the mounts

 
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