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<E28><E24> Suspension Installation, 1b of 2

Start of part 1b of 2....

 
Front Strut Replacement with Bilstein Sport 
- ------------------------------------------- 
 1. Block the rear wheels and break loose (don't remove yet) 
    all the 17mm lug bolts from each front wheel.   
 
 2. Jack the car so both front wheels are off the ground.  
    This takes the twist out of the sway bar, making removal 
    of the strut link much easier.  I jacked at the front 
    crossbar behind the oil pan and placed jack stands at 
    each frame rail. 

 3. Remove one front wheel, five 17mm lug bolts (85 ft-lbs). 

 4. Remove brake caliper (two 19mm bolts, 81-91 ft-lbs).  
    Hang it with a piece of wire so the brake hose isn't 
    supporting the caliper weight.  
 
 5. Rotor removal is optional (5mm allen bolt), but 
    recommended because it makes the strut assembly much 
    lighter. 

 6. Disconnect the sway bar link from the strut.  17mm nut 
    and 16mm flat sides on the link bolt. 

 7. Pull brake line and ABS sensor wires from the strut 
    guides.  On the left front, disconnect the brake wear 
    sensor that is clipped to the disk splash shield. 

 8. Remove three 17mm bolts from the bottom of the strut.  
    Note that these bolts need 48 ft-lbs and Locktite on 
    reassembly. 

 9. Remove three 13mm nuts (16 ft-lbs) from the top of the 
    strut and pull the strut assembly out of the wheel well. 

10. Use a spring compressor to prevent the upper strut mount 
    bearing from flying off when the top nut is removed.  I 
    used the cheap, two piece, spring compressor that hooks 
    on either side of the spring.  Each side is tightened 
    alternately, so the spring is compressed evenly.  The 
    spring only needs to be compressed enough to take 
    tension off the top nut (and allows the nut to be 
    rethreaded on the strut shaft on reassembly).  Some type 
    of power wrench, electric or air helps.  Spring 
    compressors usually have fine threads and take lots of 
    turns. 

11. Remove plastic cap and 19mm nut at the top of the strut, 
    while holding the strut shaft 6mm end.  There are 
    several options for holding the shaft and removing the 
    nut (recessed so you can't get an open end wrench on 
    it).  Ideally one has a 19mm deep socket special wrench 
    with an open end (like Griot's Garage sells) and a 6mm 
    socket to insert through the opening.  The next best way 
    is to hold a 19mm 1/2 drive socket with a vice-grip, 
    leaving the socket end open.  Then a 1/4 inch drive 6mm 
    socket can be inserted through the open socket end.  A 
    third option is to wrap the jaws of a vice-grip wrench 
    with tape and insert it through the spring coils to hold 
    the shaft.  Caution, if the vice-grip jaws damage the 
    strut shaft, the oil seal will be ruined in a short 
    time.  Use the minimum tension necessary to hold the 
    shaft and place the vice-grips as high on the shaft as 
    possible. 

12. Remove the top strut bearing, paying special attention 
    to the location and orientation of the washers.  Remove 
    the spring.  The dust cover and bump stop are discarded 
    because Bilstein front struts have a bump stop built-in 
    and a new dust boot is provided.  Retain the rubber pads 
    at the ends of the spring. 

13. Place the strut housing in a bench vice and unscrew the 
    original strut cap nut.  No special BMW tool is needed.  
    Use large channel lock pliers or a pipe wrench to loosen 
    the strut insert.  Be sure to pour out any oil out from 
    the strut housing.  Oil in the strut housing is 
    sometimes used to help transfer heat from the strut 
    insert, but Bilstein front strut cartridges are built 
    "upside down" internally compared to other brands.  The 
    bottom of the strut breaths (air out on the downstroke 
    and air in on the upstroke).  Oil in the strut housing 
    can cause hydraulic lock. 

14. Screw the Bilstein insert into the strut housing.  
    Bilsteins are supplied with a new strut cap nut and a 
    special tool so you don't have to use the channel locks 
    again.  Before installing the spring, push the strut 
    shaft _all_ the way down to lubricate the seals.  Unlike 
    the rear shock installation, the original rubber bump 
    stop and dust cover are not used.  The Bilstein shaft is 
    too large for the original pieces.  An internal bump 
    stop is built into the strut.  A new dust boot is 
    supplied with the struts which fits over a plastic dust 
    boot holder. 

15. You may want to replace the upper strut bearing (p/n 
    31331 124 508 Strut Bearing $42.95 each).  It's a 
    combination rubber mount and ball bearing for the strut 
    upper mount/pivot point.  

16. If installed, Dinan negative camber plates attach above 
    the strut bearing to offset the top of the strut inward.  
    Knock the mounting studs out of the upper strut bearing 
    and install them in the camber plate.  Then bolt the two 
    together. 

17. An alternative to the negative camber plates is the 
    factory camber correction strut bearing (31331 138 484 
    about $80 each).  They provide 0.5 degree negative camber
    on each side (or positive if turned around) versus 0.625 
    degree each side for the Dinan plates. 

18. Both front and rear springs have "pig tail" ends.  That 
    is, the end coils are not ground flat.  Reuse the rubber 
    spring pads and be sure the spring ends are at the 
    deepest points in the spring perches. 

19. Compress the spring enough to reinstall the 19mm nut on 
    the strut shaft.   

20. Reinstall strut and continue to the other side. 

21. Check front end alignment after replacing both struts. 
 
 

...End of part 1b of 2.  To be continued...... 

  Regards,

  Pete Read 
  '88 M5