How do you change the brake pads on the Saab 93?
Replacing SAAB 9.3 rear brake pads (backing off the caliper piston without requiring use of special tools or re-bleeding the brake system):
Note: SAAB 9.3's DO NOT have an hydraulic actuating piston adjusting screw on the back side of the rear brake caliper/hydraulic actuating piston assembly as the earlier SAAB 900's do.
Assuming that the portion of the procedure involving safely raising and placing the vehicle on jackstands, removing the tire/wheel and removing the rear brake caliper/hydraulic actuating piston assembly from the rear brake caliper/pad carrier bracket went OK, the interesting part then becomes backing off the caliper assembly's hydraulic actuating piston (sometimes referred to as winding the piston in) to provide the additional clearance necessary to permit the caliper/hydraulic actuating piston assembly to then be able to accommodate the new (and therefore thicker) brake pads. It requires that the hydraulic actuating piston be rotated to the right (clockwise) while at the same time being pressed inward. SAAB service garages use a special tool to accomplish this but it can also be accomplished in your home garage with everyday tools as follows:
- use the tips of a pair of heavy needle nosed pliers (or end prong snap ring pliers or a 'U' bent heavy nail's shank clamped in long nose Vice-Grip plier jaws) to engage the two holes on the face of the hydraulic actuating piston to twist the hydraulic piston to the right a few turns until it turns somewhat more freely within its rubber dust seal (lubricating around the edges of the dust seal where it meets the face of the hydraulic piston with brake fluid helps).
- place a piece of 3/16" clear tubing over the the nipple of the brake bleeder valve after removing its dust cover and OPEN THE BLEEDER VALVE keeping the clear tubing pointing upward (important to keep air from possibly entering the hydraulic assembly; a small amount of brake fluid will come out but no air should be allowed to enter)
- apply an 8 inch 'C' clamp which has a ball jointed (hopefully lubricated) pad at the end of the clamp's jack screw such that the clamp's ball jointed pad rests centered on the face of the hydraulic actuating piston and the clamp's fixed pad rests on the back side of the caliper/hydraulic actuating piston assembly. Tighten the 'C' clamp enough so that the clamp will stay in place on its own and then give it another 1/4 turn on the jack screw (do not over tighten it as it would cause damage) .
- now using a pair of channel lock pliers, clamp them firmly around the outer perimeter of the 'C' clamp's ball jointed clamp pad which is resting in contact with the face of the hydraulic actuating piston and turn it 1/4 turn to the right, such that THE PAD AND PISTON ROTATE TOGETHER. If the pad skids on ther face of the piston instead of turning together with it, include a small piece of sandpaper or a knurled (bicycle axle type) washer between the 'C' clamp's pad and the face of the hydraulic actuating piston to improve the grip. The piston MUST turn while being forced inward.
- notice that the 'C' clamp becomes a bit looser as the hydraulic actuating piston retracts slightly with the 1/4 turn so re-tighten the 'C' clamp with a 1/4 turn of its jack screw after each 1/4 turn of the hydraulic actuating piston, repeating this operation until the hydraulic actuating piston has been backed off sufficiently to provide the caliper / hydraulic actuating piston assembly adequate clearance to accommodate the total thickness of the new thicker brake pads and the brake rotor.
- reassemble the caliper/hydraulic actuating piston assembly over the brake rotor with the new rear brake pads in place in the caliper / brake pad carrier bracket and refasten it onto the caliper carrier bracket (with its two Allen head bolts - applying a thin layer of grease to the shanks of the bolts and blue loc-tite reversible thread locker to the threads - replace the dust covers over these two bolts when fully tightened / torqued).
- CLOSE THE BLEEDER VALVE (obviously a most important item) and dry it and its surrounding area off completely.
- Start the engine to power up the hydraulic brake booster and pump the brakes firmly several times which will cause the caliper assembly's hydraulic actuating piston to self adjust the caliper's hydraulic actuating piston into proper relationship with the brake rotor.
- Re-check the bleeder valve to be absolutely sure it had been properly closed and that no brake fluid had issued when pumping the brakes in the step above and replace its dust cover.
- Open the cap on the on the master cylinder's brake fluid reservoir (under hood on the driver side firewall) and replenish any lost brake fluid (using only type DOT 4 brake fluid - do not allow any dirt to enter the master cylinder's reservoir)
- Test the hand brake and test drive the vehicle with several hard stops before considering the newly replaced rear brake pad job complete and the vehicle ready to be safely returned to service.
- This is a safety related procedure so please do the work with great care.