This was done on a 1991 318is. Please Note that you should change the pads in pairs either the front or back or all around at the same time. The pictures I have taken are of the front not the rears, which differ slightly.
For the Front
- Jack up the car and remove the wheel where you want to change the pads.
Use a jack stand so you do not have to worry about the car crashing down on you while you’re under it. Remove the 2 bolts that hold the Caliper onto the wheel you will need a 13mm Socket or conventional wrench for the bolts and either a decent pair of Pliers/Channel locks (I used these) or a 15mm wrench. Please see photo for where you need to hold and where you need to unscrew.
After you have removed both screws you should be able to pull the outer part of the caliper off and have access to the pads. Be careful after the outer part is free, because its attached to a hose and you do not want to let it fall and cause any damage. After this you need to compress the brake piston, its on the far side of the caliper, and this can be done with a C-Clamp applying pressure to compress it all the way down. Another way to do it is before you take the caliper off stick a flat head screwdriver between the pad and rotor and apply pressure to compress it (be careful not to damage the rotor).
After the piston for the brakes is compressed you can seat the new pads. I recommend putting them on either side of the caliper and then putting the outer cover back on. When you put the cover back on make sure the springs are in the right position, they will push back on it some so you need to use a little pressure. Realign the screw holes and put the screws back in the way you took them out. Replace the wheel and torque to the suggested settings.
Continue to the next wheel.
After you are done start the car, and then press the brake pedal until its firm again, this will move the brake piston back to where it needs to be. I then tested to make sure the car stopped at low speed, and then drove it for a few minutes to make sure all was well. Please note it make take a couple of hundred miles to bed the pads in and they may make more noise in this time and take a little longer to stop.
Please note the Left front and Right Rear locations have brake pad sensors, which can be reused if they are in good condition. Otherwise they are very easy to replace.
Differences Between the Front and Back procedure
: The Rear is set up differently from the front, you need to remove 2 black covers under those covers are the caliper guide pin which required a 7mm Hex head (Allen wrench, or a socket attachment) unscrew them and then move to the front of the rotor and remove the retaining Clip. This can be done with a flat head screwdriver. After that you should be able to remove the housing, you need to compress the brake piston just like in the front and then replace your pads, reverse the process to put it all back together.
There you go guys, Sorry some of the pics are kind of blury, and Sorry there are not any pic of the rears I did them 1st and thought the fronts were going to be the same. I need to replace my sensors as they are busted so when I put the new ones in I will try to get some better pics.
*edit corrected the wrench size for the front rotor procedue.