HOW TO: Suspension Install

If anyone sees something that needs to be added, let me know. I'm writing this all from memory, and it's quite possible I forgot details.

THE REAR

1st, I started with the rear suspension since it's easier. Jack up the car and remove the wheel for the side you're starting on. Use jack stands for safety, dropping the car on you can make for a really bad day.

I removed the shock first; this will let the suspension droop more and saves extra work with the spring compressor. To remove the shock I started with the bottom bolt. I think it's an 18 mm bolt through the bottom of the shock. After that bolt is out, remove the interior trunk liner and undo the 2 nuts that hold the shock mount into the sheet metal of the car. When those nuts are off the shock will drop out of the bottom of the car.

Once the shock is out, I undid the sway bar to allow the suspension to droop even further. To undo the sway bar, take the nut off of the bottom of the hoop that the end link is bolted to. There's a nut/bolt that goes through the bushing, which appears the easiest at first, but will not allow the sway bar to come loose because the bolt is trapped. If you look up from the ground, you'll see the nut that needs to come off. This should let the trailing arm droop it's most without undoing the axle.

With the trailing arm drooping, take your spring compressor and squeeze the rear spring until you can pull it out. Be VERY careful with the spring compressor, springs store enough energy to cut pinched fingers off as well as enough stored energy to fly and knock all your teeth out. Never put your fingers somewhere that if the compressor fell off that you'd get pinched by the spring. I'll say once more, be VERY careful. I don't want to hear about anyone getting hurt doing this. I used one foot and stepped on the brake rotor to help make more room to pull the spring out. I also used 2 huge flathead screwdrivers to help pry it out.

Now that all your rear suspension is totally removed, it's time for installation. Install your spring first; if you're using a lowering kit, you'll probably not need to use the compressor to get the springs in. Be sure to reinstall the rubber pads on the top and bottom of the spring. I reused my old ones but new ones wouldn't be a bad idea. If you have high mileage, I'd plan on replacing them.

Next, reassemble your new shock. I used new shock tower mounts, I had them from a left over e30 project, and I think the m3 ones is upgrades for us. Remove the mount to recover the washers and shock cover from the old one. To remove them I used a wrench and a pair of vise grips. The wrench fits on the locknut, the vise grips on the shock shaft end. Reassemble with the shock cover and washer on the new shock and shock mount. Also be sure to use the new nut that came with the new shock.

Install the new shock assembly in the car by bolting the bottom of the shock to the trailing arm. Use a couple drops of loctite on the bolt, put thru the shock and tighten really tight. Use a jack and line up the top holes to the shock tower mount. Jack up the trailing arm with the studs lined up to the holes until the shock begins to compress. Switch to the inside of the trunk and install the 2 nuts that hold the shock mount to the car.

Finally reinstall the sway bar. Using the jack, align the bolt to the hole on the trailing arm. Install the nut that you pulled off earlier. Put the wheel on and congratulate yourself on a 1/4 job well done. The other rear side is a mirror image of this job you just did.

THE FRONT

The front suspension is a little harder than the rear. Start with the wheel off, remove the 3 bolts that connect the shock to the king pin. 2 of the bolts are 18 mm and are accessible from behind the brake rotor (#3 on the diagram). The third bolt is held in with a nut, so apply tools to both sides and remove (#5 and #6 on the diagram) http://www.realoem.com/bmw/showparts...21&hg=31&fg=10
Remove the brake lines and wires before undoing the rest of the system, then switch to the topside and undo the 3 nuts on the shock tower mount. At this point the whole assembly should be loose and you can lift it out. If it still feels attached to the king pin, use a flathead screwdriver and pry it off. There's an aligning dowel that held mine in place until I persuaded it off. I left the brakes and sway bar intact for this job. Be sure while the strut assembly is out that you don't let the brakes pull on the hydraulic lines.

With this assembly out of the car, compress the spring. I had to compress both sides, remove the first and re grab the spring with 1 more coil to get enough bite on the system. Continue once the spring is no longer touching #8. http://www.realoem.com/bmw/showparts...87&hg=31&fg=10
To remove the nut at the top of the shock (#4 on the drawing) I used a (6mm??) Allenwrench, 22 mm deep socket, and 2 pairs of vise grips. Look here for a picture. http://www.318ti.org/gallery/data/500/DSCF0041.JPG Some people use an impact wrench to do this instead, but since I was at a friend's house without my compressor, I made do with this. Reassemble with new shock and spring, I reused the spring pads (# 9 and # 13) but new ones wouldn't hurt. I did however replace the shock tower mount (#1) with a new one. Reassemble with all the parts in the same order you removed them.

Reinstalling the assembly, I hung the strut by the 3 studs poking thru the strut mount. I had help for this part of the project, so holding the assembly up while someone finger tightened the 3 nuts on top was easy. Line up the bottom and pull the dowel thru the new strut with the 2 bottom bolts, start them loose and tighten them gradually to keep things straight. Remember to apply a couple drops of red loctite to the bolts before installing. When the 2 bolts are mostly tight, align the king pin so you can insert the third bolt. Tighten all 3 bolts and the 3 nuts on the strut mount and this side is complete.

Do the other side, and admire your work. This job took me 6 hours or so to complete. I had to run to the store to buy 18mm wrenches to do this job; other special tools are listed above.

Good luck all.