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The following article gives detailed instructions on repairing the brakes on a BMW E31 8 series car with the Brembo "big brake" front caliper assemblies. Even though we have used a 1995 BMW 840ci to perform this installation, this article can be applied to any E31 8 series vehicle with a production date from 08/1993 with minor modifications.
See all vehicles this article applies to
E31 8 Series 850CSi
E31 8 Series 850Ci
E31 8 Series 840i
E31 8 Series 840Ci
A BMW E31 brake repair is fairly straight forward, except for the front wheels which use a "big brake" Brembo caliper assembly.
The original BMW E31 8 series is one seriously heavy beast. Its low profile and sleek looks are deceptive...this is not a light and nimble automobile. It's a V8 packing Grande Touring Coupe with an unladen curb weight of almost 4,200 pounds. To put that into perspective, that's 1000 lbs more than the E36 M3 that we cover on this site. We are not car physicists and we won't get into any fancy equations on inertia in this article. But what we can tell you is with that amount of mass moving forward at any speed, you need a serious set of front brakes to keep you from becoming intimate with the Prius waiting at the red light in front of you. It is important to keep up with your BMW E31 brake repairs, including regular inspections and replacement if needed.
BMW engineers were well aware of this issue and designed the BMW E31 eight series with 4 pistons "big brake" Brembo calipers on the front wheels squeezing massive 21-pound steel rotors. The rear calipers are the standard piston found on many other models. BMW E31 brake maintenance requires regularly inspecting your pads and rotors and replacing them both when they have become worn. A good indication that your brakes are near the end of their life is a decrease in stopping power and/or a noticeable "shimmy" in the steering wheel while stopping.
There are many different brake pad combinations on the market you can use (we have already covered those in detail - please see our E36 M3 article for a more in-depth discussion). Since the BMW E31 8 series is a luxury coupe and not used for racing, we suggest only using Genuine BMW or high-quality OEM pads. In fact, we strongly recommend it - using track or racing pads on BMW E31 8 series stock calipers can produce negative braking feedback that is not conducive for a luxury car and is highly discouraged.
Since a BMW E31 brake repair (replacing pads and rotors) on the rear wheels is identical to the BMW E36, to avoid redundancy we have left that portion out of this post . Please refer to our article on replacing BMW E36 M3 pads and rotors for the step by step procedure on replacing the rear pads and rotors on your BMW E31 8 series.
***Important note: It is standard procedure to replace the brake pad sensor wires with your pads and rotors when you perform a BMW E31 brake repair.
View the detailed parts diagram for this repair.
Includes detailed part diagrams, part numbers and links to purchase all of the required components needed to complete this repair.
Section 1 - Installing the RotorsThis post only covers replacement of the front brakes on the E31 840Ci. Please refer to our article replacing BMW E36 M3 pads and rotors for directions on replacing the 840Ci rear brakes since it is exactly the same procedure.
- Use a 17mm socket and breaker bar to slightly loosen the lug nuts on all four wheels. DO NOT remove lug nuts...you are just loosening them so they can be removed when the vehicle is lifted (note - you can loosen lug nuts with vehicle raised if you have an air impact wrench).
- Jack up vehicle and support on jack stands. Not sure how to jack and support your BMW? Read our article on the simple and safest way by clicking here.
- Remove wheels.
- Since a BMW E31 brake repair (replacing pads and rotors) on the rear wheels is identical to the BMW E36 M3, to avoid redundancy we have left that portion out of this article. Please see our article on replacing BMW E36 M3 pads and rotors for the step by step procedure on replacing your rear BMW E31 pads and rotors.
- Starting on front left wheel, remove the brake sensor wire from plastic mounting clip and disconnect. Use a small flat blade screwdriver to help pry apart the connection.
- Disconnect brake line grommet from front strut. Be careful not to tear or pinch brake line.
- Remove caliper ant-rattle clip using a flat blade screwdriver (it is easier starting at the top). **Note-some articles will suggest removing the clip with the pins (see next step)...we have found this to actually make the process more difficult on older calipers.
- Remove brake pad caliper pins using a hammer and small steel punch.
- Using a 19mm socket wrench, remove caliper mounting bolts. These bolts are located behind the caliper, and are torqued tight. You may need to give the socket wrench handle a firm hit with a rubber mallet, or use a breaker bar to free them.
- Remove caliper from rotor. Use a bungy cord to hang caliper from front strut. DO NOT allow caliper to hang freely from brake line or allow line to become twisted during handling - this could possibly cause damage to the brake line.
- Spray the rotor mounting bolt with Blaster PB or another penetrating lubricant and wait 10 minutes. It is very common for these bolts to become frozen and strip in older rotors that have not been maintained for a period of time. Remove bolt with a 6mm hex socket.
- Remove old brake rotor from hub.
- Apply some caliper lube or lithium grease to the old (or new if purchased) rotor mounting bolt. Mount the new rotor on the wheel hub and install the mounting bolt. DO NOT overtighten the bolt...it should be just slightly snug. The bolt is simply there to hold the rotor in place while the wheels are installed. It is actually the wheel bolts (lug nuts) that hold the rotor in place.
- Using a large pair of slip joint pliers, gently compress all 4 caliper pistons until they are completely retracted and flush with inside of caliper. Note - a standard brake piston compressor tool will not work on Brembo brakes.
- Mount the brake caliper on the rotor and re-install the two brake caliper mounting bolts. Remove bungee cord from car. Torque bolts to the following specifications: 110 Nm (81 ft-lb).
- Apply caliper lube to top, bottom and backs of the brake pads, and also to caliper pins. Wipe any excess lube off of inside face of pad. The caliper lube must be applied to keep the brake pads from "squealing".
- Slide brake pads into caliper until pin holes line up. You may lightly tap them with a hammer if necessary to get them into position.
- Once you have the pads in the proper position, insert the top and bottom caliper pins from the rear of the caliper. Give them a small tap with a hammer to set them in place.
- Use a steel punch and lightly lock the heads of the pins into their final position.
- Replace the ant-rattle clip, brake sensor and brake line grommet back into their respective positions.
- Using a can of brake cleaner, spray a rag and thoroughly clean off any grease or grime that may have been left on the rotor during installation. It is very important that the rotors are extremely clean, so take your time with this procedure.
- After completing the rest of the brakes, replace wheels and torque lug nuts to 110 Nm (80 ft-lb).
BMW E31 Brake Repair Finished