Suspension :: Springs Install How-To

[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 or ratchet
Dead blow or rubber mallet
Torque wrenches to accommodate 22 ft-lb to 103 ft-lb values (R50-53), 121 ft-lb (R56)



Equipment Needed:
Auto jack or lift
Vehicle stands

Alternative Tools:
Spring compressor
Air ratchet
Impact wrench/deep thinwall 21mm 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. This project was performed by justintime on his sporty Cooper. Minitauro supplied the R56 examples.


Remove the pinch bolt with an 18mm socket, using a breaker bar to loosen and a ratchet to remove.


R56 models have a flare nut on the end of the pinch bolt, loosen the bolt end only on the R56.



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 front struts will pull free without compressing the spring.


Unscrew the guide support nuts with a 13mm socket untill they are loose, then while grasping the strut, unscrew the nuts the rest of the way by hand and lower it carefully feeding past the brake line & wire then remove outward and upward from the wheel well.


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 Guide supports have a nylon stud which can be removed to allow the support to shift providing more negative camber.


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. On R56 models with the nylon stud removed, push the strut towards the engine to increase negative camber before tightening 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. Install and torque the pinch bolt to 60 ft-lb.


The R56 outerball joint is attached differently, the lift point will be under the ball joint bracket's control arm bolt.


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.


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 Koni springs had to be installed using the “buddy method”.




Torque the shaft to 22 ft-lb using a 5mm Allen socket on a torque wrench in the reverse position while holding the nut with a 16mm box end wrench.


As with the front pinch bolt, clean the rear strut lower mount bolt and apply a small amount of anti-seize. Lift the strut into place under the vehicle and guide the lower mount bolt into place. Screw the bolt in until tight but don’t apply complete torque at this time.


Clean the upper mount bolt threads and apply a small amount of anti-seize. Raise the trailing arm with a jack and position the top of the strut within the chassis recess, line-up the upper mount holes and install the bolts, torque to 41 ft-lb.


Torque the lower strut mount on R50-53 models to 103 ft-lb.


For R56 models torque to 121 ft-lb.


Put the brake line and wire in their strut brackets, replace the lower bolt dust cover if your model has them, remount the wheels, torque the lug bolts at 89-92 ft-lb for R50-53, or 103 ft-lb for the R56 models, lower the vehicle.

[justintime]

:]

[drmike@txwerks.com]

Nice write-up!

[bluzeke]

Thanks for posting!

[COR BLMY]

great write up
NICE TIP ...
"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"

[golden_child]

Does anyone think think this should be stickied? Mods?

[RedSkunk]

Will come in handy next month!

[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. One thing to consider is cost, the MINI/BMW Hazet 21mm strut nut socket and a batch of MINI OEM nuts are much less expensive than the 22mm Stahlwille socket.

[FUEGO]

Great write-up! Thanks for taking the time to do it for the rest of us. It sure would have been handy when I installed M7 springs about 7 months ago .

The 21mm Hazet socket is available at www.samstagsales.com for under $60 as Hazet p/n 2593-21, but best if you call or email them for a quote. I got mine for $49.99 as a previous customer when I ordered some other tools with it. They carry lots of specialty tools for automotive use. They're also a good source for the 36mm shallow socket used for the MINI oil filter cap.

[THE ITCH]

K-huevo
Excellent write up!!! Thank you for your efforts. I would like to add one thing. Be sure when re-installing the front struts that the alignment wing on the strut is in line with the split in the knuckle. If you are using a jack to lift the knuckle back up it is very easy to bend the alignment wing if it is not in the slot. It is also difficult to see because it is behind the strut. Especially if you are doing this job alone and are trying to keep the alignment with the top of the strut.
The special 21 mm socket can be made a lot cheaper if your handy. I got a deep 21 mm socket from Sears and cut a window in it just like the OEM tool has to insert the allen wrench. I cut the window using a dremel with an abrasive cut off tool. It worked just great.
Thanks again for all your work, Steve

[justintime]

Originally Posted by THE ITCH

K-huevo
Excellent write up!!! Thank you for your efforts. I would like to add one thing. Be sure when re-installing the front struts that the alignment wing on the strut is in line with the split in the knuckle. If you are using a jack to lift the knuckle back up it is very easy to bend the alignment wing if it is not in the slot. It is also difficult to see because it is behind the strut. Especially if you are doing this job alone and are trying to keep the alignment with the top of the strut.
The special 21 mm socket can be made a lot cheaper if your handy. I got a deep 21 mm socket from Sears and cut a window in it just like the OEM tool has to insert the allen wrench. I cut the window using a dremel with an abrasive cut off tool. It worked just great.
Thanks again for all your work, Steve

I noticed that it wouldnt move easily unless they were lined up,good tip its kinda hard to tell if they are aligned or not

[bluzeke]

. . . just wondering?

In this kind of DIY installation, is it a foregone conclusion that the car will have to be realigned or is there a reasonable expectation that the replacement parts can be installed in a manner that does not affect the original alignment? If the car "seems" to track OK on a post surgery test drive, (that is, identically to the way it did before the change) is that good enough or could there be more subtle and new alignment issues that might be going unnoticed?

[justintime]

im having mine aligned again soon. keith said it is a good idea to have it done.

[THE ITCH]

bluzeke
If you are installing springs that would alter your ride height or camber plates an alignment is definately something that you should do. Even if your reason for taking these parts out is not to change anything it would still be a good idea to do an alignment. Lots of people drop the rear subframe to change the rear sway bar and do not do an alignment. IMO I think that is a mistake.
Steve

Originally Posted by bluzeke

. . . just wondering?

In this kind of DIY installation, is it a foregone conclusion that the car will have to be realigned or is there a reasonable expectation that the replacement parts can be installed in a manner that does not affect the original alignment? If the car "seems" to track OK on a post surgery test drive, (that is, identically to the way it did before the change) is that good enough or could there be more subtle and new alignment issues that might be going unnoticed?

[OSUBeaver]

If you were to just hit the shaft nut with an impact wrench, would it come off without needing the special socket?

Recently we tried lowering a friends Audi A4, and the nut was inaccessible even with an offset box wrench. After he took it to the shop the guy said he just used an impact wrench and the shaft can't spin fast enough so the nut comes off.

[simplekid15]

Justin has the front of your car lowered yet?

[justintime]

Originally Posted by simplekid15

Justin has the front of your car lowered yet?

haha nope, only the back kinda gives it a mean stance though

[billie_morini]

Hey K,
This is an excellantly prepared, "how to." Lots of good photos. Clear & concise notation, too. Thank you.

[Fatherdeth]

Originally Posted by OSUBeaver

If you were to just hit the shaft nut with an impact wrench, would it come off without needing the special socket?

Recently we tried lowering a friends Audi A4, and the nut was inaccessible even with an offset box wrench. After he took it to the shop the guy said he just used an impact wrench and the shaft can't spin fast enough so the nut comes off.

Yes, while I can't verify that this will cause any harm, you can use an impact wrench to take the strut shaft nut off. The torque spins it faster, so it comes right off. When I lowered mine a few months ago, it was the ONLY way to get it my driver's side off. When I took the strut assembly off the car, I noticed the smell of burnt grease. It seems like the bearing had gone bad and the nut was seized, so a zip with the impact wrench took it right off. Again, I don't know the long term effect of doing it this way. I would think that since they designed it to come off in their manner, they did it for a reason.

[PGT]

great write up! I've got a set of passthrough sockets....I need to check and see if I've got a 21mm in the set. I believe I do.

edit - just saw the post about using an impact. It's ok to use it to remove the nut, but NEVER use it to tighten it back down. You can and will snap the strut.

[PGT]

suggestions for where to source the tool? I just checked my kit and I've only got up to 19mm.

Originally Posted by 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. One thing to consider is cost, the MINI/BMW Hazet 21mm strut nut socket and a batch of MINI OEM nuts are much less expensive than the 22mm Stahlwille socket.

[k-huevo]

Post#9 for the Samstag Sales link and your favorite MINI or BMW parts departments.

[PGT]

ahh, thanks! I admit I didn't read every post :(

[groove67]

The only reason you need the special socket is to hold the shaft while you loosen it, could you use a racheting wrench that large, if it is available? I ask because Bilstein has the same type shaft design and I did it the hard way (standard open end wrench) when I lowered my camaro.

[THE ITCH]

You will also need the special tool to re torque the nut on the strut shaft. If you do not hold the strut shaft it will spin when you re torque.
Steve

Originally Posted by groove67

The only reason you need the special socket is to hold the shaft while you loosen it, could you use a racheting wrench that large, if it is available? I ask because Bilstein has the same type shaft design and I did it the hard way (standard open end wrench) when I lowered my camaro.