Front brake pad replacement       

Before jacking the car, pry off the center trim covers on the front wheels, then break the wheel retaining bolts loose.  A 1/2" breaker bar fitted with a 3" extension and 19 mm socket makes a great lug wrench.

Jack the car and support it on stands, then remove the front wheel bolts and wheels.  If you leave one at the bottom, the other 3 will come out easily.  Then you can push the bottom of the tire with your toe as you remove the last bolt.

Double check the security of the jack stands.

Have a straightened coat hanger wire handy to suspend the caliper.  Or invert a car wash bucket or something similar to use as a stand to set the caliper on (I generally prefer this method except when removing the discs - in that case, the bucket usually gets in the way when I'm trying to remove the 17 mm caliper mount frame bolts).  You can also use a short bungee cord to hang the caliper from the car's suspension spring.  

Put the key in the ignition and unlock the switch so the wheels can be turned.  Turn the wheel full right for passenger side work, and full left when working on the driver's side (you can work with the wheels straight head, but turning them gives the easiest access).  Look on the inboard side of the caliper - you should see two cylindrical protrusions at the front, top and bottom.  Use a screwdriver to pry the plastic caps out of the holes.  Use a 7 mm hex wrench ("Allen wrench") (a T-40 Torx can also be used) to remove the two retaining studs.  You can get hex and Torx bits that mount to a 3/8" drive ratchet, and that sort works best here.  At this poit, I believe all cars use the hex bolts, but a Torx will also work.   After the bolts are loose, be careful not to let the caliper fall, as that could damage the rubber brake line.

Pry the spring clip off by using a screwdriver to pry outward at one of the two points where the ends press into the holes in the caliper.

Pull the front of caliper firmly toward you.  The object is to rotate/rock it a bit to compress the piston and give some clearance.  If the rotors are worn to the point that there is a lip around the edge, you'll have to rock the caliper a lot to provide enough clearance.  If there is no lip on the rotor, the caliper should slip forward and off the rotor at this point.  Lay the caliper on the inverted bucket, or suspend it from the car's suspension spring with the coat hanger wire or bungee cord.  Be careful if using coat hanger wire - it wants to go every which way, and it could easily put your eye out.  If you use a coat hanger, make sure it is securely twisted so it won't fly open, and make sure the ends are tucked away where you can't contact them.  As I said, I prefer something of the right height to lay the caliper on, or a bungee cord.

If the caliper is balky and you can't compress the piston enough, try prying the caliper forward and off the rotor.  In extreme cases you'll need to crack the bleeder valve to allow the piston to be compressed. This makes it easier, but it also increases the danger of getting fluid on the pads and air in the system.

Remove the outer pad from the carrier.  The inner pad is held in the piston cup by three spring fingers - pry the pad out.

If removing the discs, first put a screwdriver or something in one of the ventilation slots in the outer circumference of the disk, rotate the disk until the screwdriver jams against the caliper carrier, then remove the T-30 screw and the wheel guide pin (10 mm wrench) that secure the disc.  You will then need to remove the two 17 mm bolts on the inner side of the caliper carrier that secure he carrier to the hub.  Use a breaker bar and 17 mm socket to break the bolts loose, then use a ratchet and socket to remove the bolts.  The bolts are secured with thread locking compound, so they are pretty tough to turn for the first few turns.  Once the carrier is removed, the disc will fall off, so be prepared to catch it.

The choice of brake pads is, in my opinion, very important.  Stock Saab pads are excellent - they have very good sensitivity, stop extremely well, are quiet, and don't wear rotors appreciably.  They do wear fairly fast though, they're quite expensive, and they're pretty bad for creating lots of reddish-black dust that accumulates on the wheels.  Most aftermarket pads strike me as being way too hard - the pedal sensitivity is often terrible.  Not only do I want a pad that has good maximum grip and resists fade, but I also want a pad that responds positively to light to moderate pedal pressure - I don't want to have to do leg press exercises three times a week just to be able to stop the car.  More important than absolute pressure requirements is the TIME required for the brakes to begin stopping.  Pads that require high pedal pressure waste precious fractions of a second before they begin to stop the car.  Many hard aftermarket pads don't wear at all - but they chew through brake rotors like crazy!  Hard pads also tend to glaze, and the pedal pressure requirements increase with age.

Having said all that, I must say that I'm extremely impressed with PBR Deluxe (Deluxe, not MetalMaster) brake pads.  The pedal response is wonderful - they're very responsive, very direct, and the responsiveness, the feeling of stopping power and utter control of the brakes is really a joy.  The maximum stopping power is as good as any I've ever used.  They do not give off any noticeable dust at all.  They're not very expensive at all - much cheaper than stock Saab pads.  After about 55 K miles, the front pads appear to be about half worn, although the rear pads were ready for replacement.  I think the front pads will probably go between 90 K and 100 K miles (the ought to be replaced when they get down to around 1/8" in thickness, in my opinion).  Surprisingly, the rotors are worn very little.  

I have noticed two drawbacks to the PBR Deluxe pads: 1) they have been prone to squeaking; 2) they take a fraction of a second to get a good, positive grip on the first application in very wet conditions in highway driving.  Others have not noticed these issues.  NOTE: After about 50 K miles I replaced the pads with stock Saab pads, without replacing or turning the rotors.  The pedal pressure was disappointingly high, so I ordered new stock rotors, mounted those and reinstalled the PBR Deluxe pads.  On inspection, the Saab pads didn't appear to have bedded in completely, even after 1500 miles or so (I should have either had the rotors turned or replaced them).  The Saab pads produced unbelievable amounts of ugly reddish-brown dust - on a single 600 mile road trip, the wheels started out clan and ended up absolutely covered with dust.  It's more than a little irritating!

Tips to avoid squeaking:  Bevel all the edges of all pads with a file - just round off all the outer corners and edges.  Also, coat the backing surfaces of the pads with Permatex Disk Brake Quiet (follow directions on the bottle).  I recommend doing this to any new pads, and, in fact, any time that you might remove and reinstall the pads (or any time the pads get squeaky).

OK, so reassembly:

If you removed the disc, reposition it on the hub and lightly secure it with the countersunk screw and wheel locator stud.  Put thread locking liquid on the threads of the two 17 mm bolts, line up the caliper carrier piece and tighten the bolts to 66 ft-lbs.  I used the less aggressive blue thread lock (the red is extremely aggressive and may require heat to release the bolt).  I am not sure which compound is specified, so consult your manual or a Saab dealer to be certain.  After installing the caliper carrier bolts, gently tighten the wheel alignment pin and the countersunk screw to retain the disc.

Compress the piston until it's flush with the caliper body.  They make piston compressors for this purpose, but I haven't found one that fits the Saab caliper (NOTE: worked fine on the '94 Aero caliper, but not on the '91).  I use a C-clamp.  You can either lay a piece of metal or plywood across the cup opening and clamp against that, or you can put a socket down into the cup and clamp against that.  Be advised that enough fluid may be displaced that the reservoir will overflow; although it's unlikely, keep an eye on it.  Crack the bleed valve if necessary (don't let any fluid get on the pads!).

Install the inner pad by pushing the three spring fingers into the piston cup.  Put the 7 mm hex-driven studs into the caliper, but make sure they're back far enough that you can put the caliper onto its mount.  Put the outer pad in place in the carrier - friction side toward the disk - as you're guiding the caliper into position.  Align the studs, screw them in and tighten securely.  NOTE: The Haynes manual gives a spec for the front caliper retaining bolts as 66 foot-pounds, but I feel sure this is for the two 17mm bolts that secure the caliper mount frame, not the 7 mm hex "pins" or studs - I have not found a spec for them, so I always just tighten them securely (I feel quite certain that 66 ft-lbs would shear these bolts in two).  Install the two plastic dust caps.  

Reinstall the spring: It's easy once you know how to do it. Orient the spring so that the two ends that go into the holes are toward the front (the looped ends that clip over the fixed carrier are more rearward).  Push the bottom end into its hole while positioning the bent end against the carrier, then drive the spring into the hole with a couple of hammer taps.  Now align the other end over its hole and drive it into the hole with a hammer.  Now you can pry the other bent end back and into position over the carrier tab.  You can use either pliers or a screwdriver; I prefer pliers.  Tap everything into position with the hammer.  Get into the car and press the pedal a few times - make sure it feels OK.  It will probably be very soft at first until the pads contact the disc.  Press the pedal only about half way down, then release and repeat, until the pedal hardens up.  Inspect alignment visually before reinstalling the wheels.

Before you reinstall the wheels, have a good look at all the CV joint boots to make sure there are no splits and no cracks are developing.  Best view is with the steering wheel turned all the way toward the side you are inspecting; rotate the wheel a full turn while inspecting the the valleys of the folds in the boots and the shoulders where the big end of the boot clamps onto the hub.  Check for loose clamps and grease leakage too.