In this tech article we will discuss replacement of the front brake pads on the E30 BMW. While this tech article is specific to the E30, it applies to most other BMW models with floating calipers as well.
I had begun to notice that my brake had started to squeak a bit. Shortly afterwards, I noticed the “brake linings” light come on in the dash. This is a a visual system BMW uses to indicate that the brake pads will soon need replacement.
Wheel lugs should be 17mm. Remember to loosen the lugs while the car is on the ground. Then remove them once it is on the stands. Instructions on jack up points can be found here: http://www.rtsauto.com/e30-jacking-points-also-relevant-information-to-other-cars/
You’ll see two sensors coming out of the calipers on the driver’s side. Follow these wires back to were they connect and unplug them.
Remove two 13mm bolts at the top and bottom of the caliper. You will need at 13mm and 15mm wrenches.
The calipers will hinge and slide up. You may need to use a flat screw driver to pry the pads loose. Feed the sensor wire through the gap in the back and slide the caliper off of the cradle.
Use a zip tie, rope, or bungie cord to hold the caliper out of the way. You do not want to leave the weight of the caliper hanging on the brake lines.
If your brake lines look cracked/worn or if you would like upgrade to braided brake lines, now is a great time. Remember you will need to bleed your brakes after…
There will be two 19mm bolds holding the bracket in place. These will be on there so if you have an impact now is the time to use it. Otherwise break out the breaker bar and get ready to muscle it. Once the bolts are gone the bracket should slide right off.
There is a small 5mm hex bold holding the rotor in place. Be sure to spray it with some penetrant like WD-40, etc.. because if you strip this bolt you will have a TON more work ahead of you. It is also a good idea to replace these if they are looking even a little worn.
Once the bolt is removed you can pull of the rotor. You may need to hit it with some wood or soft faced hammer.
Grease can affect braking it gets on the rotors. So time to soaking everything down in some brake cleaner.
You can now either take them to be turned or put in some new ones. It’s a good idea to put a dab of anti-seize compound on one side of the threads to prevent stripping the next time you remove the brake discs.
Now that the rotors are installed, it’s time to compress the caliper pistons. You’ll want to do this in order for the new brake pads to fit. As the old brake discs wear, the piston gradually comes more and more out of the caliper, making it impossible for the new pads to fit.
In order to compress the pistons, first remove the brake fluid reservoir cap, this will relieve the pressure on the system, and make it easier for you to push the pistons. Next, use a large C-clamp as shown in the photo, to slowly push the piston back into the caliper. The caliper pistons should slide back with a minimal amount of force.
BMW recommends you torque them to 65 ft/lbs.
Slide the brake pads into the caliper bracket. Then install the new brake wear sensor in place. Keep in mind that there is only one brake wear sensor on the right front.
It may take a little force to get the caliper over the pads. Once it is in place. You can put in and tighten the two bolts that are the caliper in place.
Just put the wheels back on and take it for a spin. Make sure you bed the brakes. This will break (no pun intended) in the pads. Here is detailed write up on how to do that. http://www.zeckhausen.com/bedding_in_brakes.htm or http://www.tirerack.com/brakes/tech/techpage.jsp?techid=85.