[///Mposter]

DIY rear brakes for the 2011 BMW x3 (35i ) chassis F25.
The reason I am writing this is because I was surprised to find out that my rear brakes had completely gone down to the metal backing without tripping the sensor. I had to park the SUV overnight while trying to source parts. I'm pretty much on top of my maintenance and even had a NC inspection just weeks before, so it baffled me as to why they wear down so fast. As I learned, rear brake biasing is used to prevent the front from dipping ,at the expense of the rear pads. My case was unique as only the outer right rear pad wore down. I believe I may have gotten only 8000 miles out of the set of pads due to the one faulty pad.


Parts:
Brake disc rotor
34-20-6-790-362
Rear brake pad sensor
34-35-6-790-304
Rear brake pads repair kit with bolts
34-21-6-796-741

List price: 126.44pads+41.99 pad sensor+ 148.80 rear rotor
+ 148.80 rear rotor.= $466

Crown BMW discounted price.
94.99pads+24.88pad sensor+ 106.29rear rotor
+ 106.29 rear rotor.= $354.42

Tools:
Breaker bar ( cheater bar)
17mm for lug nuts
Jack stands
Jack
Size 6 hex for rotor screw
T30 for the EHBrake screws
4" or 6" extension
13mm open end wrench (caliper)
(13mm socket alternative)
15mm open end wrench (caliper )
Flathead screw driver
T45 for the caliper side EHbrake
Large C-clamp/brake compression
16mm for caliper bracket

Loosen lug bolts slightly using the 17mm socket . Jack the car up and secure using the jack stands. I used some extra wood blocks on the front tires to keep the car from rolling back and forth while removing the rear tires.

Get in the car and release the parking brake. Remove the rear tires and then quickly remove the EHbrake connector on each side. If you have comfort access, keep your keys away so that you won't get the yellow brake light indication . ( the car woke up at some point and the dash lit up with the yellow brake light)

Use the 6-hex to loosen the rotor screw , but you don't have to remove the screw until right before you are removing the rotor in a later step. If you are having trouble loosening this bolt, use the flat screw driver in the cooling fins of the rotor to prevent rotation of the rotor while trying to loosen the bolt.

Start removing the brake pad sensor wiring & EHBrake connector from their clips and brackets so that it won't be attached to the EHbrake bracket, and will be out of the way.

Use the T30 to remove the EHbrake sensor. An extension was helpful on aft side bolt( pictured left) and no extension on the forward side bolt(pictured right).

Gently pull and rotate to remove the EHbrake from the caliper.

Now you can loosen the caliper bolt with a 13mm wrench while holding the slider bolt with a 15mm wrench. I ended up using a 13mm socket on one that was a bit stubborn . Repeat for bottom bolt .

Pull the caliper away slowly and remove the pads and prepare to remove the brake pad sensor on the inner pad. Put the caliper back in place or rest it on something. Use a flat screw driver to push the sensor off the pad. Be careful not to lose the small tension spring that holds the sensor.
Notice how worn my pad was compared to a normal worn pad. You can see the sensor was never triggered for me.

Moving on, using a T45 on the caliper side, insert it into the EHBrake hole and rotate it clockwise. Now you can depress the caliper piston with your thumbs , a C-clamp, or a brake compression tool. I used my thumbs .

View the level of brake fluid in the reservoir . Remove some if it is too high after brake piston compression.

Here is a picture of the new pads and hardware.

I had to replace my rotors this time since there was surface damage . But if you didn't have to , you could skip ahead to new hardware install into the caliper bracket .

I used the 16mm socket and extension to remove the caliper bracket.

Now I removed the rotor bolt and also used two lug bolts so that when I kicked the rotor or use a mallet , it will not fall off and damaged foot or concrete.

I then cleaned the surface of the hub with a wire brush ( optional)

I installed the new rotor and re-inserted the rotor bolt.

I installed the new hardware into the caliper bracket. Reinstalled the 16mm bolts. Placed the new pads into the new hardware holders. I used an orange-red brake quiet on the outer pad as I think the inner one rotates and used grease. I installed the caliper . Used the new 13mm bolts provided. Installed the pad sensor. I pushed the EHbrake wiring into the clips but did not connect the connector.

Repeat removal and install for drivers side rotor and brake pads.

Now clip in the EHbrake sensor on both sides. Put car to on/accessory by tapping the start button once. Put the hand brake on and listen for the EHbrake system to rotate and lock the brakes. It will be abnormally longer the first time. Cycle it a few times until it is normal (short cycle). Start the car and pump the brakes. Check to see if there is any weird noises before putting the tires on. Go back and check your work if you do hear something .