Strut Spring Install

[k-huevo]

Tools Needed:
13mm, 16mm, 18mm, and 21mm standard sockets; 21mm strut socket BMW # 31 2 210 (Hazet)
Long 6mm & 5mm Allen wrenches, 5mm Allen socket
16mm box end wrench, 17mm open end wrench
Ratchet
Long breaker bar
Dead blow or rubber mallet
Torque wrenches to accommodate 22 ft-lb to 103 ft-lb values R50-53, 121 ft-lb for the R56.



Equipment Needed:
Auto jack or lift
Vehicle stands

Alternative Tools:
Spring compressor
Air ratchet
Impact wrench and 21mm thinwall deepset socket

Lift the Vehicle and place on stands, remove the wheels, pull the front brake lines and ABS/pad sensor wire off the strut, and disconnect the stock drop link from the strut using a 16mm socket for the nut and a 17mm open end wrench to hold the bolt from behind the mount. The drop links shown during the spring install procedure are aftermarket that requires a 14mm socket and 13mm open end wrench. The main project was performed by justintime on his sporty Cooper. Minitauro supplied the R56 examples.

[k-huevo]

Remove the pinch bolt with an 18mm socket, using a breaker bar to loosen and a ratchet to remove. R56 Models have a ribbed flare nut on the end of the bolt, loosen the bolt head only.




Apply lubricant to the lower end of the front strut where it enters the steering knuckle.


Place a stick on the jack’s lift pad and use as leverage under the lower spring perch to compress the spring and push the strut out of the steering knuckle. A few taps with a dead blow hammer may be needed to break it free. Exercise cautions if a hand is needed to stabilize the strut, do not place the hand or fingers between the strut & stick or any place where it could be trapped if the strut shifts abruptly.


R56 models will not require compression of the spring.


Unscrew the guide support nuts while grasping the strut, once freed, lower the strut carefully feeding past the brake line and wire then remove outward and upward from the wheel well.

[k-huevo]

Remove the bearing dust cap and place the strut on its side. Use a block of wood to leverage the Allen wrench and body weight to leverage the strut shaft nut using the special 21mm strut socket on a long breaker bar. This can be performed with the strut upright but it requires much upper body strength. Unscrew the top nut until the nylon lock has cleared the shaft threads.


Without a spring compressor the nut can be removed safely using the “buddy method”. As a partner applies weight on the guide support, unscrew the last remaining threads, the partner releases pressure smoothly, and off comes the upper mount. justintime (seated) and simplekid15 (standing) demonstrate how it’s done.


A spring compressor will provide stability and facilitate removal if the install is performed solo.


R56 models have a nylon stud on the guide support, removing the nylon piece allows the guide support to shift a little, providing an extra half degree negative camber if desired.

[k-huevo]

After the replacement spring has been installed and the strut shaft nut tightened to 47 ft-lb, feed the strut into the strut tower, guiding the bolts through their mounting holes, while still grasping the strut, screw on the guide support nuts by hand to hold the strut in place then complete the fastening with a ratchet and torque to 25 ft-lb. For R56 models with the nylon stud removed, push the strut towards the engine to increase negative camber, before securing the nuts.


Clean the pinch bolt threads with brake cleaner and a wire brush; afterwards apply a small amount of anti-seize. The pinch bolts are exposed to oxidizing elements; anti-seize will help prevent a frozen bolt that could shear when attempting to extract.



Place a block of wood on the jack lift pad and raise the steering knuckle from under the outer ball joint nut. R56 location shown here.


Install and torque the pinch bolt to 60 ft-lb. On R56 models, after inserting the bolt hand tighten the end nut, apply torque to the bolt head only.

[k-huevo]

Torque the drop link to strut body at 41 ft-lb.


Be sure to place the drop link behind the strut to avoid making this mistake; oops.


Return the brake line and ABS wire to their strut body mounts and replace the bearing dust cover cap to declare the front strut has been completed; yippee!

Moving to the rear strut, remove the anti-sway bar drop link.


Pull the brake line & ABS sensor wire from the strut body.

[k-huevo]

Unscrew the bolts on the strut’s upper mount using a 13mm socket.


Loosen the lower strut bolt with a 21mm socket and breaker bar, attach a ratchet to unscrew, grasp the strut before removing the bolt completely to keep it from dropping and remove the strut.


Remove the strut shaft nut with a 16mm box end wrench and long 5mm Allen wrench. A spring compressor can be used on the stock springs but the H&Rs had to be installed using the “buddy method”.

[justintime]

fun day :]

[k-huevo]

While MINI uses 21mm & 16mm strut shaft top nuts, the rest of the metric world uses 22mm & 17mm; replacements are also easier to find. Shown is a Stahlwille 1051 22mm.