BMW E92 M3: Installing H&R Sport Plus (Race) Springs
The M3 comes with very capable suspension; ours has EDC (Electronic Damper Control) so it can adjust to suit most conditions/people. However, I was looking for a bit more road feel and sharpness and H&R provided this in the form of Sport Plus (Race) springs. This installation is the EASIEST spring swap ever, the DIY guide I used to do this can be found at http://www.m3post.com/forums/showthread.php?t=183011
Start to finish with breaks and stopping to take these pictures took me about 2.5 hours, but allow more time if you are not an avid DIYer.
I found some lightly used springs in the forum classifieds for a deal, they are a GREAT place to save on mods before buying new.
Also, if you are installing springs and have not done so already, you may want to remove the factory strut alignment pins to allow max negative camber, detailed on my M3 page HERE.
Standard Disclaimer: ANY USE OF THIS INFORMATION BY YOU IS AT YOUR OWN RISK, I ASSUME NO LIABILITY FOR YOUR USE OF THIS INFORMATION.
I like to tackle the most difficult part of an installation first so in this case it was the front driver side. The driver side front and rear have headlight leveling switches that need to be disconnected before dropping the suspension which adds a step, and the front is considered to be more difficult than the rear.
Before lifting the car, break all of the front wheel lug nuts loose, but don’t remove. The car can be jacked using the central jack point and then jack stands are placed under the OE side jack points:
Once on jack stands, the lug nuts and wheel can be removed and you will see what you’re in for:
I started under the hood by breaking the strut nut loose, the EDC controls have to be removed to access this. Unplugging the wiring harness by pressing the two release tabs, and gently lifting the EDC cap up you will see a small plug where it connects to the damper. This plug can be disconnected by lifting straight up- no release:
With the EDC cover out of the way, the strut nut can be loosened (don’t remove yet) using a 10mm socket wrench to hold the strut piston rod and a 21mm wrench to break the surrounding nut loose. I attempted to use painters tape to prevent the strut brace ring from getting beat up, even though the tape looks ripped it did its job:
Back under the car, the headlight leveling switch can be disconnected from the lower control arm using a 10mm open end wrench on the flats behind the bracket and a 10mm socket wrench to loosen and remove the nut. I replaced the nut so it won't be lost and tucked the switch arm up out of the way:
Sensor wiring and brake lines are pushed out of their respective holders on the strut tube:
The sway bar link is removed from the strut housing, a 19mm open end wrench is used on one side to keep the ball joint bolt from rotating and a 16mm socket wrench is used to remove the nut. The nut is replaced so it won't be lost and the link is positioned out of the way:
[CAUTION: An automotive spring can exert a LOT of force that can cause injuries- Please proceed at your OWN RISK]
I compressed the spring by placing a jack under the lower ball joint and jacking:
With the spring compressed, spring compressors can be installed by hand and tightened on two of the lower spring coils. The spring compressors seen here are available through the FREE loaner tool program at AutoZone:
The 10mm socket wrench and 21mm wrench are again used on top to completely remove the strut nut:
The jack can be lowered to allow the strut to drop down/free. You may have to use your hands to push the strut piston down to allow it to be pulled out to the side and clear the fender, the spring might need a little help as well. If the strut bearing cover comes out with the assembly it can be reinstalled by pushing up and back into place. The spring compressors can be carefully removed from the spring, you will not need these to reinstall the strut with the H&R springs:
Front spring is installed, making sure the spring ends line up with the upper and lower spring stops, and all above reassembled and installed: strut piston rod nut (using jack to raise/hold in place as the assembly is aligned and reinstalled), anti-roll bar link, all hoses/wiring clamped back into strut tube holders, and for driver side the headlight leveling switch is reconnected to the lower control arm. Passenger side can be completed using the same steps. TIS Torque specs and instructions at bottom.
Similar to prep steps used in front, the car is jacked at the rear center support and jack stands are placed under the side rear jack points. It is NOT advisable to jack using the differential. ALWAYS USE WHEEL CHOCKS IN FRONT OF THE FRONT TIRES (you can't see them in the pics because they are some small collapsible chocks from an old 280Z but they are there):
Once on jack stands and with the parking brake on, the wheel lug bolts can be removed along with the wheel:
The driver side has the headlight leveling switch; it can be removed as in front using a 10mm wrench and a 10mm socket wrench and placed out of the way after the nut is reinstalled so it won't be lost:
The lower control arm is supported with a jack under the solid area below the spring:
The lower control arm has two bolts that will need to be removed, the shock bolt and the wheel hub bolt. FIRST, the shock bolt can be removed using an 18mm socket with a breaker bar at first and then a socket wrench. NEXT, the wheel hub bolt is removed using a 21mm wrench on the nut to hold while a breaker bar then socket wrench are used with a 21mm socket to remove the bolt:
The jack can be lowered once both bolts have been removed. The lower control arm is pushed a bit further down with one hand while the spring is removed with the other. I did this by pushing the spring down and out of the upper cup, and then lifting up and out of the lower control arm:
The new spring is installed making sure the lower and upper rubber stops are aligned with the spring ends. The lower rubber insulator has two tabs, the smaller tab fits through a hole in the control arm and the larger tab fits the larger rectangular hole facing toward the side of the car:
The jack is used to jack the lower control arm back into place; you will have to play with it a bit to get the optimal height and alignment to get the bolts through. Install the hub bolt/nut FIRST (a little tricky to align, once you figure it out the other side will be easy), and NEXT the shock bolt (careful not to cross thread the bolt). You can use a screwdriver in between the hub mounting point and shock base to get it aligned. The final tightening to specific torque values should be done with the suspension at normal height; this can be done with the wheels remounted and the car backed on to ramps- TIS torque specs and instructions at bottom:
Don’t forget to visit your tire shop for a 4-wheel alignment…………….
TIS Torque Specs: TIS instructions below with torque specs-