Rear spring removal/installation - c900
Here's a job that should be fairly easy, as long as you can get the bolts off and aren't afraid of jacking and working under the car.
Difficulty: 2/5
Tools required:
-Long, flat screwdriver for removing center cap
-Lug nut/bolt wrench
-Trolley jack
-Two jackstands, cinder bocks, or old rims to stand the car on top of, because you'll need to support both sides at the rear
-16mm socket and ratchet or breaker bar
-16mm open-end wrench
-Penetrating oil
Parts required:
-4 self-locking nuts
-New springs or spacers, if you're looking to correct your ride height, or want to get a toppola.
If you want good overload springs, the ones made by SAS (sasab.com) have done me proud since summer of 2008. They are progressive-rate, hence the coils closer together at one end. It doesn't matter if you install these upside-down or right side up, as long as they're both the same way round (hell, that probably doesn't even matter, but I'm nitpicky). If you're looking for spacers, the SAS urethane spacers also seem to be holding up well. I think the cars for the USA market are higher in the front than in the back to meet some regulation. Most people lower the front, but I like raising the back, because I often move house in my SAAB.
http://saabworld.net/attachment.php?attachmentid=2123
Here's the SAS overload spring with 1/2" urethane spacer on the left and the stock '86 N/A spring on the right.
Start out by jacking the car up in the rear. DO NOT jack from the middle of the axle, as this will bend it. Put both jackstands or other such supports under the jacking points, so that the car is securely supported. Remove the rear wheels.
I came across the most difficult-to-remove bolt I've ever met while doing this job...
http://saabworld.net/attachment.php?attachmentid=2128
...so I would spray all bolts with your favorite penetrating oil the night before starting work, and use copious amounts of anti-seize all the way up the shafts of the bolts when reassembling.
Now, it's time to get down-and-dirty. You should do one side at a time, so that your rear suspension doesn't come entirely apart. Having the other side to anchor it all together is very helpful.
If you have a rear sway bar, remove it from the trailing arms and swing it down and out of the way first. Likewise, if you have a rear emergency-brake, remove its cable mount from the trailing arm you're working on.
Start by removing tension from the shock by jacking up the trailing-arm a bit. Then you can remove the bolt that holds the shock to the trailing arm safely. Then, raise the arm a bit more, and stick something under the axle near the side you're working on. Lower the arm again, so that the axle rests nicely on its support, but there is no stress on the bolt that affixes the axle to the trailing arm. This is important to get right, so that you can remove the axle-to-trailing-arm bolt easily and safely. Doing it with no support under the axle makes it more difficult, and you're liable to damage the flexible brake line. Doing it with no support under the trailing arm can lead to a spring flying out once the bolt is removed :o.
http://saabworld.net/attachment.php?attachmentid=2119
This shows the axle, supported by the trolley jack, and the trailing arm being let down slowly on the spare-tire jack after removal of the axle-to-trailing-arm bolt.
So after you let the jack holding the trailing arm down, the spring should just fall right out. Well done!
Now, you need to put it back together...
Insert the new spring where you took out your old one. Changing the shocks will likely require a hacksaw or at least a pipe wrench to get the old shocks off their top mounts, but it is pretty self-explanatory, if you plan to do this as well. Then jack the trailing arm back up, compressing the spring with the arm.
When the arm is level with the axle, you may have some trouble getting the bolt to slide in. If so, you'll need to play with positioning. I used a C-clamp and a jack to move the axle to the place I wanted:
http://saabworld.net/attachment.php?attachmentid=2127
http://saabworld.net/attachment.php?attachmentid=2126
After this, I was able to pop the bolt right in! Once you've got the axle on, attaching the shock to the trailing arm should be a picnic. I see little reason to do shocks and springs at the same time, because the shock is only held on by one more bolt, and can be done easily at any time without removing the axle.
Finally, torque the two bolts to 15-20 ft-lbs, put on the wheel and do lug nuts to 66-81 ft-lbs (or lug bolts to 78-92) and go for a test drive!
