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

Start of part 2 of 2....
 

Rear Shock Replacement with Bilstein Sport 
- ------------------------------------------ 
This procedure assumes the original load-leveling shocks 
are replaced with Bilstein Sports.  If you're only replacing 
springs there's enough room to remove the original 
load-leveling shock and use a spring compressor without 
disconnecting the hydraulic line to the accumulator in
the wheel well. 
 
 1. Block the front wheels and break loose (don't remove 
    yet) all the 17mm lug bolts from each rear wheel.   

 2. Jack car and insert jack stands. I jacked at the 
    differential and placed jack stands under the rear 
    suspension crossbar support points. 

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

 4. Take out the trunk mat and trim pieces from both sides 
    held in place with plastic screws.  

 5. To disable load-leveling, pull the spare tire and remove 
    the white plastic cover over the load-level pump.  Then 
    unplug the electrical connection to the pump. 

 6. Climb into the trunk to access the top shock mounts. 
    The passenger side has a plastic tank which limits 
    access to the shock tower nuts.  Remove the 10mm bolt 
    and move out of the way.  There is no need to disconnect 
    the rubber lines.  

 7. The driver side has an amplifier mount which limits 
    access.  Remove the two phillips head screws and move 
    out of the way. 

 8. Remove three (tight access, 16 ft-lbs) 13mm nylock nuts 
    at the top of the shock.  

 9. Remove lower shock bolt with 22mm wrench (92-105 ft-lbs). 
 
10. Disconnect the hydraulic line (on load-leveling shock) 
    from the accumulator inside the wheel well and remove 
    the shock. 

11. No need to disassemble the original shock.  The shock, 
    spring, and small pieces (see list) are all new. 

12. Be sure to compress the new Bilstein shock rod _all_ to 
    lubricate the seals before installing the spring. 

13. Bilstein Sport rear shocks have six adjustment grooves 
    0.39 inches or 10mm apart (I previously rounded it to 
    eighths or 0.375 inch, but it's 10mm).  Change rear ride 
    height by moving the circlip that holds the lower spring 
    perch.  You need 0.5 to 0.75 inch rake along the rocker 
    panel measured just behind the front wheel and just in 
    front of the rear wheel.  Setting the Bilsteins at the 
    fourth groove down from the top with Dinan springs, 
    gives 0.75 inch rake along the rocker panel.  Front and 
    rear rocker panel heights, with Dinan springs, measured 
    7.75 inches and 8.5 inches respectively. 

14. Use the new rubber pads (see list below) at each end of 
    the springs.  The springs ends are not ground flat.  Be 
    sure to seat the tail of the spring so the spring ends 
    are at the deepest point in the spring perches. 

15. Use the new dust cover (protection tube) and bump stop 
    (absorber) from the list below.  The dust cover clips to 
    the lower part of the rubber bump stop. 

16. Replace top shock mount (guide support - see list 
    below). 
    
17. Compress the spring enough to reinstall the 17mm nut on 
    the shock shaft while holding the shaft with a 6mm open 
    end wrench.  Unlike the front strut, there is easy 
    access to the nut.  
    
18. Check, and if necessary, replace the paper gasket 
    between the body and the top of the shock (p/n 
    33521 118 480  Gasket $0.67 each).
     
19. Reinstall shock and continue to the other side. 
 
 
Load-Level Elimination Parts from E28 535i fische 
(about $63 total) 
 
                                   Parts Fiche 
Quan Part Number   Description     Item Number    
- ---- ------------- --------------- -------------  
 2   33521 124 572 Spring Pad           14        
 2   33521 124 507 Spring Pad            3        
 2   33521 124 575 Protection tube      12        
 2   33521 124 573 Adsorber             11        
 2   33521 126 680 Guide Support         4        
 2   33521 125 651 Washer                8        
 2   33521 125 649 Support Cup           2        
                                                                                                 
 
 
 
Sway Bar Replacement, Suspension Techniques (ST) 25mm/19mm 
- ---------------------------------------------------------- 
Sway bar installation is much easier than shocks and springs.
It's a straight-forward bolt and unbolt procedure.  Just make
sure both wheels are off the ground at the same time so the 
bar isn't twisted.   
 
 
Front Bar 
- --------- 
 1. Block rear wheels and jack up the car so both front 
    wheels are off the ground (no twist in bar).   I jacked 
    at the front crossbar behind the oil pan and placed jack 
    stands at each frame rail. 

 2. Disconnect the lower part of the sway bar link from each 
    side (17mm nut and 16mm flat sides on link bolt).  Replace
    the links if the boots are damaged (p/n 31351 134 582 
    front sway bar link $ 25.18 each). 

 3. Remove two 13mm bolts from each sway bar bracket.  There 
    are four threaded holes on each frame mount, but only 
    two holes in the bracket.  The stock bar used the 
    inboard holes.  The ST bar worked best using the 
    outboard holes.  The ST urethane front bushing didn't fit
    (correct 25mm hole size, but outer part sized  for 535i 
    bracket) so the stock rubber bushing was reused 
    (p/n 31352 226 001).  

 4. Quality control on the front bar was less than perfect.
    The innermost hole was 0.080 inch thicker at one side of 
    the hole than the other (end wasn't completely flat before
    the holes were drilled).  Without a flat surface, the 
    suspension link bolt can't be tightened correctly.  To make 
    the inboard hole useable, I filed the bar flat and then 
    rounded the resulting sharp edge to prevent stress cracks.   

 5. Install the new bar.  I started at the middle hole, which 
    works out to be the same stiffness as stock.  The inner hole
    is the most stiff while the outer hole provides the least 
    front roll stiffness. 
 
 
Rear Bar 
- -------- 
 1. Block front wheels and jack up car so both rear wheels 
    are off the ground (no twist in bar).  I jacked at the 
    differential and placed jack stands under the rear 
    suspension crossbar support points. 

 2. Remove the load-leveling u-clamp from the center of the 
    bar.  If load-leveling is retained, the u-clamp is 
    reinstalled on the new bar and rotated to adjust rear 
    ride height.  Otherwise the u-clamp is removed. 

 3. Unbolt the "dog bone" shaped sway bar links from the 
    trailing arm, 13mm bolt and nut.  If the rubber inserts 
    look worn replace the link (p/n 31351 131 622 rear sway
    bar link $9.30 each). 

 4. Remove the 13mm bolt from each sway bar bracket and 
    remove the sway bar.  One side of the bracket slides 
    into a slot while the other end is bolted. 

 5. The stock sway bar ends just slip into a rubber bushing 
    in the "dog bone" shaped link.  To make the bar 
    adjustable, a metal bushing is pressed into the rubber 
    insert and the ST sway bar is bolted to the link with a 
    14mm bolt and nut.  To insert the metal bushing, wet the 
    rubber and use a vice to press it in -- a 1/4 inch 
    socket can be used to help start the bushing, backed by 
    a 15mm socket on the other side of rubber. 

 6. Lubricate the new ST urethane bushings with a waterproof 
    grease, such as for trailer bearings, and install the 
    new bar. 

 7. I started at the outer hole, which works out to 24% 
    stiffer than stock.  The inner hole gives even more rear 
    roll stiffness. 
 
 
Sway Bar Adjustment 
- ------------------- 
Adjustment of the front or rear bar is a simple process of 
moving two bolts to different holes.  Just jack the car so 
both wheels are off the ground and move the bolts to 
different holes in the bar.  Moving the bolt inward (shorter 
arm) increases roll stiffness at that end of the car while 
moving to the outer holes (longer arm) gives less roll 
stiffness. 
 
For more understeer, either stiffen the front bar (move to 
inner hole) or loosen the rear bar (move to outer hole).  
Create more oversteer by stiffening the rear bar (move to 
inner hole) or loosening the front bar (move to outer hole). 
 

...End of part 2 of 2.   

  Regards,

  Pete Read 
  '88 M5