Tools & Supplies needed:Liquid Wrench Penetrating Oil7mm Allen Wrench7mm Allen BitT5 Bit15mm Socket15mm Flare Nut Crowfoot SocketTube/extenderFlat head screwdriverSocket WrenchesTorque WrenchBrake Pads (Front & Rear)Brake Wear Sensors (2)Cross-Drilled Rotors (Front & Rear)Wheel ChocksRugsNeedle-nose Pliers
Front Brake Assembly Diagram
Front Rotor Assembly Diagram
Rear Brake & Rotor Assembly Diagram
I always play safe. I chock both ways and chock front and rears in a staggered pattern!
Pop the hood and open the brake fluid reservoir. You might want to put a rag around it just in case some brake fluid may come out later.
Jack up the car
Pre-loosen lug bolts in a `star` pattern
Take out lug bolts
Take out the Brake Wear Sensor wiring from its holder by prying out the vent dust caps.
My car has the wear sensors at the front driver and rear right sides.
pull out wiring from the cable holder
Disconnect Wear Sensor Wiring from its receptacle.
Make sure connections remain clean.
Use a needle-nose pliers to gently disconnect the brake wear sensor from the caliper.
NOTE: Be careful not to lose the little metal clip. Do not work the connector “back and forth” or “side to side”. These things easily break.
If you cannot find the little metal clip or cannot take the sensor out from the caliper, it might be stuck on the brake pad. Leave it and we’ll get it out later.
We will need to take out the plastic protective caps to be able to access the Guiding Bolts that hold the Caliper Housing to the Brake Carrier.
There are 2: one at the top and one at the bottom
Pry out the cap with a flat head screwdriver. Be careful not to wreck both the caps and the boot.
Once loose, you can take it out with your fingers.
Clean the plastic protective boot caps and set aside.
For the top Guiding Bolt, you can either use a 7mm Allen Wrench or a 7mm Allen Bit Socket. This will of course depend on space.
I prefer the Allen Bit Socket for ease of use.
Since the bolt is actually facing the opposite, to loosen it will be your clockwise!
Pull out the 2 Guiding Bolts and set them aside.
The Caliper slides back and forth on these bolts, so make sure they are clean.
For the bottom Guiding Bolt, I used the Allen wrench with a tube to extend for greater leverage.
Because of the tight space, an Allen wrench can only fit here.
Here is a view of the 2 Guiding Bolts still in their protective boots.
WARNING: Do not allow the Caliper assembly to hang unsupported. The brake lines are not meant for this.
Pry out the Anti-Rattle Clip with a flat-head screwdriver.
Be careful that the clip does not fly off when popped from the caliper.
Pull out the Caliper Housing from Rotor.
Lay Caliper assembly supported (not hanging by its brake lining!)
Now, would be the time to prepare the new Brake Pads.
Apply Anti-Squeal compound on the back of the Brake Pads (not the face of the pads where the pad meets with the rotor surface!)
Because the new brake pads will be thicker, you will need to compress the piston using a C-clamp. Use the old brake pad to do this!
Here is an image of the Caliper assembly without the Brake Pads.
Take note of the Piston. The brake pad clips will mate with the piston cylinder.
New Brake Pads in place.
Set the Caliper assembly aside for now while we proceed with replacing all Rotors.
In the next section, I will be installing new Zimmermann Cross-Drilled Rotors.
There are 2 bolts holding the Brake Carrier to the collar.
Take these bolts out.
For the top bolt, I used a 15mm Socket wrench with no problem.
For the bottom bolts, it is a different story! Because of the cross member, there is no space to use the shallowest socket at all!
Instead, I used a Flare Nut Crowfoot Socket. Perfect!
An image of the Brake Carrier with the top and bottom hex bolts loose.
Proceed to pull out the Brake Carrier from its collar.
Apply penetrating oil to the hex bolt.
In my case, I stripped one bolt even with the oil and heat applied and had to resort to using some special tool to take it out.
Loosen and remove the hex bolt using a T5 bit
You should now be able to take out the old rotor from the hub.
With the front rotors, I had a hardtime taking it out from the hub for it was seized. I had to hammer it out using a piece of 2x4 as cushion on the rotors. Although I did not really care too much if I warped it in the end. I do not have to reuse it!
A view of the rear rotor taken out
For the rear ones, take note of the parking brake
Ahhh, the new rotors! Zimmermann Cross-drilled Rotors!
Install new rotors and secure with a 5mm hex bolt.
NOTE: Do not overtighten these guys!
Re-install the Brake Carrier
Re-install the Caliper assembly (now with the new Brake Pads), Brake Wear Sensors (where applicable), and Anti-rattle Clips.
NOTE: Remember to reinstall the Protective Boot Caps after tightening the Guiding Bolts in place.
Re-install the wheels.
I used this special BMW tool to guide and align the wheels lug holes with the hub. It makes life easier!
Mount the wheels using the guide tool.
Preinstall all other 4 lug bolts, take out the guide tool, and then preinstall the 5th lugh bolt.
Torque at 90ft-lbs.