Installing Mini Cooper (R50/53) Springs and Rear Control Arms
The Mini Cooper S handles great from the factory, but the ride height is a bit too high for some. Some will argue that putting lowering springs in a Mini will have it riding on the bump stops and it will handle horribly. What they don’t understand is that BMW designed the suspension in these cars with progressive bump stops that are meant to be part of the spring travel to provide a smooth ride but allow it to handle great as well. I have had no issues and did not trim the bump stops since that would alter the progressive design intended by the engineers.
I chose APEX Suspension Systems springs for their cost (mine were a low-mileage set found even cheaper on the forum classifieds) and they have turned out to be a great value. Originally intended as a stop gap for coilovers, I think they work so well that they will become permanent. I also installed Hotchkis adjustable rear lower control arms (aka rear camber links) from Way Motor Works so I could adjust the camber back to spec during the wheel alignment.
This write-up was helpful to me: http://www.minicooperspeed.com/mini-cooper-strut-springs-or-lowering-spring-installation
Standard Disclaimer: ANY USE OF THIS INFORMATION BY YOU IS AT YOUR OWN RISK. I ASSUME NO LIABILITY FOR YOUR USE OF THE BELOW INFORMATION.
NOTE: TIS Instructions and torque specs at bottom of write-up for reference.
Front Spring R&R:
First step is to jack up the front side that you will be working on (using jack stands of course) and after placing jack stands under the car, removing the wheel/tire:
Remove the brake line and brake sensor wire from the strut retainers carefully:
Remove sway bar end link from strut: Use a 17mm open end wrench on the flats behind the sway bar link joint to prevent rotation while loosening the bolt with a 16mm socket/ratchet. Remove the sway bar link from the strut mount after removing the bolt:
You may want to soak the base of the strut to steering knuckle union with PB Blaster so that it will come apart easily:
Remove the strut pinch bolt: After soaking both ends of the bolt liberally with PB Blaster and allowing some time for it to soak in, I used an 18mm socket with a ratchet and/or breaker bar to loosen and remove the pinch bolt. I also used anti-seize with this bolt on reassembly after reading some nightmare stories on the forums of people breaking these off in the steering knuckle due to rust-weld.
Remove the three upper strut mount nuts: In my case this required a 13mm socket (OE nuts may be the same….or not):
The steering knuckle did drop but not enough to free the bottom of the strut- I had to compress the suspension to remove the strut assembly after removing the three upper strut mount nuts in order to get enough room to clear the knuckle. This will require some creative thinking on your part or a spring compressor that works with the strut installed. It also helps to twist the steering knuckle while pulling the strut assembly out at an angle:
With the strut removed, the plastic cover can be removed using a standard screwdriver to access the nut:
Compress spring using a spring compressor (I have always borrowed one from a McParts store like AutoZone using their tool loaner program) and remove strut assembly nut:
There are some different ways to remove the nut from the strut but none work better for me than an impact wrench, I have air but electric works too. If you don’t have access to one of these, I have used creative solutions like the one below in the past- a 13/16 spark plug socket and the correct HEX wrench with Vice Grips, no guarantees this will work for everyone or every car. Pic below is merely to illustrate a potential alternative to an air wrench, in the past I would have cut the hex wrench down so that the Vice Grips and the wrench on the spark plug socket were closer together, and a closed end wrench on the spark plug socket will always work better than an adjustable:
After removing the nut you will see that there is the spring, rubber insulator, top hat, washer, strut mount, and nut in that order:
When installing the front spring in the front strut assembly, make sure the spring ends are positioned at the rubber pad stops and that the rubber pads are positioned correctly on the lower and upper mounts. Assembly is spring, rubber insulator, top hat, washer, strut mount, and nut in that order. I found that the spring compressors were not required to reassemble the strut assembly, but you may need a helper to start the nut while you compress the spring by hand:
Installation is reverse of removal J Remember to reinstall brake lines and brake sensor wiring in strut holders:
Rear Spring R&R:
After jacking and supporting the rear with jack stands, remove the brake line and brake wiring from the shock holders:
Remove the lower shock mounting bolt using a 21mm socket with breaker bar at first and then socket wrench:
Remove the upper shock mount bolts using a 13mm socket (extension optional):
Disassemble the rear shock assembly by removing the nut, using an air wrench (16mm socket) or a 5mm HEX wrench/16mm box end wrench:
Reassemble the rear shock assembly making sure the spring ends meet the rubber pad stops and reinstall. Installation is reverse of removal (don’t forget to replace the brake lines/wiring in the shock holders):
Hotchkis Rear Lower Control Arm/Camber Link Installation:
Start by removing the inside bolt/nut for the lower control arm/camber link. The exhaust shield may need to be “adjusted” to access the nut:
After removing the inside bolt/nut, the outside bolt is removed. You can see that there is some degree of camber adjustment in the factory setup:
After removing the OE camber link and comparing to the new Hotchkis piece, you can see that not only will it be adjustable but stronger as well. I adjusted the new Hotchkis link to be the same length as the OE piece removed, bolt center to bolt center, to get it close enough to drive to the alignment shop with no issues. Installation is reverse of removal, I found it easiest to grease the camber links before installation- Make sure the zerk grease fittings are pointing down when installed and that the right angle zerk is mounted to the inside mounting point:
TIS Instructions and Torque Specs:
AFTER COMPRESSING SPRING WITH SPRING COMPRESSOR
AFTER COMPRESSING SPRING WITH SPRING COMPRESSOR