BMW Brake Repair – 3 Series E46 2003 325ci

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BMW brake repair

BMW Brake Repair – 3 Hours

BMW Brake Repair

The BMW Repair Guide used this 2003 325ci for the following article. To see other repairs on our site using this actual car, please click on the image below!

A BMW brake repair is a relatively easy job for the “do it yourself” home mechanic. It can save a BMW owner close to a thousand dollars when compared to having the dealership do the work.

There are some BMW repairs that can save the “do it yourself” mechanic a fair amount of money…then there are some repairs that can save a sh@t load of cash. Excuse our French, but there is no better way to put it. Doing your own BMW brake repair will save you so much money, you will be cussing the dealership in languages you never thought you could speak.

Why is doing a BMW brake repair yourself so inexpensive? Two words…parts and labor. The dealership will only install factory BMW parts, which will cost you a fortune and are completely unnecessary. Since most BMW owners are intimidated by working on their own brake system, the dealerships take advantage of this and charge an arm and a leg for labor. Also unnecessary. Changing the brake pads and rotors on your BMW is fairly simple and requires just a modest amount of mechanical acumen. In fact the hardest part of the job is getting the old pads and rotors off of the car, especially if your last BMW brake repair was done 10 years ago and the vehicle has been sitting outside. Pads and rotors will rust to the wheel hub making the use of a large heavy hammer necessary to get them off.

“The dealership will only install factory BMW parts, which will cost you a fortune and are completely unnecessary.”

We have found that the best parts for a BMW brake repair can be found at your local auto parts store, or online at Amazon.com.  Unless you are a hardcore purist, there is no need to use BMW factory brake parts on your vehicle. Your biggest decision will be deciding between semi-metallic or ceramic brake pads. We like using ceramic because they can handle higher braking temperatures, recover more quickly after frequent stopping, and generate less brake dust. Usually the price difference between ceramic and semi-metallic brake pads is minimal…so it’s really up to your own preference.

Parts, Tools and Supplies

Parts
Front and rear brake rotors
Front and rear brake pads
Rotor set screws (four needed)
Front brake pad sensor
Rear brake pad sensor

Tools and Supplies
Air impact wrench (or 1/2″ breaker bar)
1/2″ ratchet
3/8″ ratchet
17mm socket
Large flat blade screwdriver
7mm hex socket
6mm hex socket
4lb sledgehammer
Synthetic brake lubricant
PB blaster
Brake piston compression tool
Torque wrench

Procedure

  1. Jack and support both ends of your vehicle using the “jack stand” methodPlease click here to learn how to properly jack and support your vehicle for this repair.
  2. Using and air impact wrench (or 1/2″ breaker bar) with a 17mm socket, remove the lug nuts and wheels from the entire car.BMW brake repair
    1. Starting with the driver’s side (left) front wheel, remove the anti-rattle clip using a large flat blade screwdriver as shown below.BMW brake repair
    2. Use a flat blade screwdriver to remove the protective plugs off of the back of each caliper guide bolt.BMW brake repair
    3. Using a ratchet and 7mm hex socket, remove the two caliper guide bolts securing the caliper to the caliper carrier.BMW brake repair
    4. Remove the brake pad wear sensor by unclipping it from the inside brake pad. Note – Brake pad wear sensors are only located on front left and rear right brakes.BMW brake repair
    5. Grasp caliper with both hands and remove from brake rotor. You may need to use a large flat blade screwdriver to pry the brake caliper piston back off of the interior brake pad too loosen the caliper up enough for removal.BMW brake repairBMW brake repair
    6. Remove the brake pads from the caliper and throw away.
    7. Using a 17mm socket wrench, remove the two bolts securing the caliper carrier to the steering arm. These bolts are torqued tight…use a hammer or a breaker bar if necessary to initially loosen bolts.BMW brake repair BMW brake repair BMW brake repair
    8. Spray the rotor set screw with PB Blaster or equivalent, and let sit for 5 minutes. The rotor set screws get very rusted and are difficult, if not impossible, to remove if not sprayed with a penetrating oil.BMW brake repairBMW brake repair
    9. Use a 6mm hex socket to remove the rotor set screw. Remove old rotor from wheel hub. You may need to “bang” the rotor with a hammer if it is rusted to the hub, which is normally the case.BMW brake repair
    10. Disconnect the brake pad wear sensor by removing it from the steering arm wire mounts. Open the junction box in wheel well and unplug the brake pad sensor. Replace with new sensor. The right rear sensor is done exactly the same, the only difference being the junction box is located forward forward of the wheel well in rear fender.BMW brake repair BMW brake repair BMW brake repair
    11. Install new brake rotor and secure with new rotor set screw.
    12. Use a brake piston compression tool to compress the caliper piston back into the caliper. This is necessary to create enough space for brake pads to clear brake rotor.BMW brake repair
    13. Reinstall the pad carrier. Torque the two pad carrier bolts as follows: Front carrier bolts 110 Nm (81 ft-lb), Rear carrier bolts 65 Nm (48 ft-lb).BMW brake repairBMW brake repair
    14. Using a bottle of synthetic brake disk lubricant, generously apply a labor to the back of each brake pads…especially where they slide on the calipers. Wipe any excess grease of the front of the pads.BMW brake repairBMW brake repair
    15. Place the pads inside the brake caliper as shown below. Slide the caliper back on the rotor.BMW brake repairBMW brake repair
    16. Reinstall the caliper guide bolts and torque to the following value: 30 Nm (22 ft-lb).
    17. Reattach the new brake pad sensor by clipping it back it the rear brake pad. Note – it may be snug…try using a flat blade screw driver to “push” it into its slot.BMW brake repair
    18. After all of the brake maintenance is completed, replace wheels and torque lug nuts to spec. Road wheel to hub – 110 Nm (80 ft-lb)

Brake system bleeding/flush
Although not mandatory, it is strongly suggested you flush and bleed your brake system after every BMW brake repair. Read our article on flushing and bleeding your brake system for more details.

Brake bedding/pad “break in” procedure
Brake bedding (break in) procedures differ among manufacturers, and there will be instructions included with your pads on which brake bedding technique is recommended for you brand. If there are no instructions in the box, use Google. Every pad manufacturer has readily available instructions on bedding procedures and you should follow them exactly.

If you cannot find any break in procedures for your pads, us the following general guidelines. They are usually sufficient for any type of street brakes. These procedures are best done on a “side street”…they are not recommended in traffic.

  1. After reaching medium speed (35-40 mph) engage brake pedal to slow car without coming to a complete stop. Release pedal quickly and do not drag brakes. Repeat four or five times.
  2.  At higher speeds (50+ mph) engage brake pedal to slow car without coming to a complete stop. Release pedal quickly and do not drag brakes. Repeat five times.
  3.  Do not hold brake pedal. Park car for approximately 20 minutes or until brake rotors are completely cool to the touch. If during the above steps the brake pedal becomes soft or brake fade is noticed, park the car immediately for approximately 20 minutes. Do not hold brake pedal.

 

Repair finished
If you have any questions or comments, please feel free to comment on this article or contact us. And congratulations for Doing It Yourself!

The Repair Difficulty Level displays graphically how challenging the repair is, from easy to advanced. Easy repairs usually require very few tools, have short repair times and do not require jacking and supporting the vehicle. As the difficulty level rises, expect the repair to demand more time, specialized tools, and better understanding of mechanics to complete the job.