Courtesy of M5P0ST.com Technical training. Product information. M Carbon Ceramic Brake System BMW Service Edited for the U.S. market by: BMW Group University Technical Training ST1302 3/1/2013 General information Symbols used The following symbol/schematic diagram is used in this document to facilitate better comprehension or to draw attention to very important information: A Contains important safety information and information that needs to be observed strictly in order to guarantee the smooth operation of the system. Information status and national-market versions BMW Group vehicles meet the requirements of the highest safety and quality standards. Changes in requirements for environmental protection, customer benefits and design render necessary continuous development of systems and components. Consequently, there may be discrepancies between the contents of this document and the vehicles available in the training course. This document basically relates to the European version of left-hand drive vehicles. Some operating elements or components are arranged differently in right-hand drive vehicles than shown in the graphics in this document. Further deviations may arise as a result of the equipment specification in specific markets or countries. Additional sources of information Further information on the individual topics can be found in the following: • Owner's Handbook • Integrated Service Technical Application. Contact: conceptinfo@bmw.de ©2012 BMW AG, Munich, Germany Reprints of this publication or its parts require the written approval of BMW AG, Munich The information contained in this document forms an integral part of the technical training of the BMW Group and is intended for the trainer and participants in the seminar. Refer to the current respective information systems of the BMW Group for any changes/additions to the technical data. Information status: February 2013 BV-72/Technical Training Courtesy of M5P0ST.com M Carbon Ceramic Brake System Contents 1. Introduction.1 2. Technical Data.3 2.1. Comparison of the M Compound to M Carbon Ceramic Brake System.3 3. Design of Brake.4 3.1. Introduction.4 3.1.1. C/SiC brake disc.4 3.2. Brake Disc.4 3.2.1. Design and special feature.4 3.2.2. Wear characteristics.6 3.3. Brake Pads.11 3.3.1. Overview.11 3.3.2. Wear characteristics.11 3.4. Protective Plate.11 4. Function.12 4.1. Braking Performance/Braking Effect.12 4.1.1. Cold brake and cold tires.12 4.1.2. Warm brake and warm tires.12 4.1.3. Wet conditions.12 4.1.4. Winter operation.12 5. Comparison to M Compound Brake.13 5.1. Front Axle Brake.13 5.1.1. Brake disc.13 5.1.2. Brake disc hub.14 5.1.3. Brake caliper/pad.16 5.2. Rear Axle Brake.17 5.2.1. Brake disc.17 5.2.2. Brake disc hub.17 5.2.3. Brake caliper/pad.18 5.3. Brake Booster.19 6. Service Information.20 6.1. General Information.20 6.2. Dismantling/lnstallation.22 6.3. Breaking in New Brake Pads/discs.26 7. Sample Boundary Catalog.27 7.1. General Information.27 Courtesy of M5P0ST.com M Carbon Ceramic Brake System 1. Introduction Starting in March production of 2013, M Carbon ceramic brakes are available as an option (2NK) on the M6 Coupe, M6 Convertible and F06 M Gran Coupe vehicles. M Carbon ceramic brakes will also be available as an option in the future with the FI 0 M5. The M Carbon ceramic brake system is also called BMW C/SiC brake system (see chapter entitled "Design"). Depending on the situation, this offers a further increase in active safety compared to the standard M Compound brakes. In a direct comparison it also offers: • Even more direct/spontaneous use of brake force • Higher fading stability • Significantly reduced wear • 19.4 kg / 42.7 lb weight reduction of rotating wheel masses • Increased reliability for winter driving conditions thanks to corrosion resistance. M Carbon ceramic brake, front axle 1 M Carbon Ceramic Brake System 1. Introduction As a visible distinguishing feature to the M Compound brake system the brake calipers are painted in gold. The M Carbon ceramic brake system can only be installed with 20" M wheels due to the larger brake discs at the front. The 20" M wheels must also be ordered as an option in conjunction with the Carbon ceramic brake option 2NK. The brake discs are manufactured by Brembo SGL Carbon Ceramic Brakes GmbH. 2 Courtesy of M5P0ST.com M Carbon Ceramic Brake System 2. Technical Data 2.1. Comparison of the M Compound to M Carbon Ceramic Brake System Designation Unit M Compound M Carbon ceramic brake system brake system Front brake 6 pistons, fixed caliper 6 pistons, fixed caliper Diameter x Thickness, brake disc [mm] 400 x 36 410x38 Friction path/Friction ring width [mm] 76.0 88.8 Weight of brake disc [kg / lbs] 13.9/30.6 7.8/17.1 Weight of brake caliper and pads [kg / lbs] 7.0/15.4 7.4/16.3 Rear brakes 1 piston, 1 piston, floating caliper floating caliper Diameter x Thickness, brake disc [mm] 396 x 24 396 x 26 Friction path/Friction ring width [mm] 64 64 Weight of brake disc [kg / lbs] 9.3/20.5 5.4/11.9 Weight of brake [kg / lbs] 6.7/14.7 6.6/14.5 caliper and pads 3 Courtesy of M5P0ST.com M Carbon Ceramic Brake System 3. Design of Brake 3.1. Introduction 3.1.1. C/SiC brake disc Currently carbon fibers are generally used in the development and application of composite ceramics such as the M Carbon ceramic brake disc. The abbreviation "C/SiC" is used for carbon fiber reinforced silicon carbide. In addition to the intended load, which impacts the brake disc upon braking, this material cannot be subject to any mechanical or thermal mechanical deviating load (see also chapter entitled Service instructions). A Due to the special feature of the material, the current information and specifications in the documents in the Integrated Service Technical Application must be observed in each case. 3.2. Brake Disc 3.2.1. Design and special feature The composition of the M Carbon ceramic brake disc is made up of two different materials. The support body (2) with the cooling ducts (1) have a sintered silicon carbide ceramic base that is reinforced with a high content of carbon fiber direction oriented strands. The inner and outer friction coating (3) has a much a higher ceramic content. M Carbon ceramic brake design 4 M Carbon Ceramic Brake System 3. Design of Brake Index Explanation 1 Cooling duct 2 Support body with cooling ducts and ribs 3 Outer friction coating The brake disc body is designed using a special shaped part. The fibers (also called "rovings") are set down, aligned and fixed similar to the process observed for the manufacturing of fiber-reinforced plastic. They have a high carbon content. This forms the support body with the cooling ducts and ribs. A thin outer and inner friction coating with high ceramic content is fixed to the support body. The braking surface blank, comprising the support body and the two friction coatings, is then baked in a special oven at a high temperature, whereby the shaped part is then dissolved. Sanding, boring, lapping or milling can take place as part of the finishing work; as is customary for all ceramics, only with diamond tools, water jet or laser. During cooling a visible cracked pattern is formed on the friction coating, this is called the relaxed microstructure. The relaxed microstructure also remains visible after the final finishing process. This is normal for this Carbon ceramic brake disc and also remains visible to varying degrees when driving. M Carbon ceramic brake, relaxed microstructure Courtesy of M5POST.com 5 M Carbon Ceramic Brake System 3. Design of Brake A _ _ This surface structure formed by the relaxed microstructure has no influence on the performance of the brakes. 3.2.2. Wear characteristics The M Carbon ceramic brake disc has a much longer service life than the M Compound brake disc as a result of its special friction coating. In an ideal scenario (everyday driving) these brakes can last the service life of the vehicle. Thanks to the design with the hard friction coating, this technology only shows very minimal signs of heavy wear on the brake disc. Depending on the thermal load, there can be a slow, continuous loss of strength. This is primarily through oxidation of the carbon fibers of the support body at very high temperatures like in sport driving usage. The brake disc also loses weight in the process. It is a service-specific wear measuring procedure in the development phase which is used at a later stage. There are currently three wear indicators for the M Carbon ceramic brake disc in addition to checking the surface for damage: • Three wear indicators per friction surface located every 120°. (1) • Minimum brake disc weight. (2) • Minimum brake disc thickness. (3) 6 M Carbon Ceramic Brake System 3. Design of Brake _ % • • • • • . . • • • 8 CM U. »- M Carbon ceramic brake wear indicators W # • Index Explanation 1 Wear indicators 2 Min. weight 3 Min. thickness Courtesy of M5POST.com 7 M Carbon Ceramic Brake System 3. Design of Brake As part of a brake service the wear indicators are the primary factors when determining disc wear. New brake disc showing no wear as indicated by the wear indicator. 8 M Carbon Ceramic Brake System 3. Design of Brake Brake disc showing partial wear by a portion of the wear indicator being exposed. Disc with partial wear Courtesy of M5POST.com 9 M Carbon Ceramic Brake System 3. Design of Brake Wear indicator is greater than 50% exposed, brake disc is considered worn beyond limits and should no longer be used. Disc must be replaced, total wear A For necessary service work the current information and specifications in the documents in the Integrated Service Technical Application must be observed in each case. 10 Courtesy of M5P0ST.com M Carbon Ceramic Brake System 3. Design of Brake 3.3. Brake Pads 3.3.1. Overview The brake pad structure of all brake pads is adapted to the surface of the friction coating of the M Carbon ceramic brake discs. The brake pads do not have their own special friction coating like the brake discs. The size of the friction surface and the thickness of the friction pad are adapted to the parameters of the M Carbon ceramic brake discs. 3.3.2. Wear characteristics The wear characteristics of the M Carbon ceramic brake pads are better than that of a M Compound brake pad. Roughly double the service life of a M compound brake pad can be expected. 3.4. Protective Plate The front brake disc protective plates at the swivel bearing have been modified and are specific to the M Carbon ceramic brake. 11 M Carbon Ceramic Brake System 4. Function 4.1. Braking Performance/Braking Effect 4.1.1. Cold brake and cold tires The spontaneously greater braking effect can reduce the stopping distance slightly depending on the situation, caused by the spontaneously higher friction between tires and roadway at the start of braking and the resulting quicker heating-up of the tires. 4.1.2. Warm brake and warm tires The braking effect in a warm state could be considerably higher, but will be roughly the same as the M Compound brake system, as it is restricted by the adhesion of the tires. High braking frequency and heavy usage such as braking from maximum speed to standstill are no problem. Also for extreme loads there is no direct material destruction by overheating or fading tendency. 4.1.3. Wet conditions Without a dry brake function, for example after washing wheels, a slight deceleration of the higher braking effect can be felt, similar to the wet M Compound brake system. Through the high braking effect of the M Carbon ceramic brake system the contact force of the brake pads in the dry brake function is withdrawn as otherwise it would be noticeable for the passengers. This is done by updated software to the Dynamic Stability Control. At low speed and cautious braking an audible sound may occur with wet M Carbon ceramic brakes or in the case of high humidity. This is due to the current design of the M Carbon ceramic brakes. A_ In the case of complaints the current information and specifications in the documents in the Integrated Service Technical Application must be observed in each case and a PuMA case created if necessary. 4.1.4. Winter operation A big winter advantage of the M Carbon ceramic brake disc in comparison to the M Compound brake disc is its corrosion resistance. 12 M Carbon Ceramic Brake System 5. Comparison to M Compound Brake 5.1. Front Axle Brake 5.1.1. Brake disc The friction ring width (swept area) of the front M Carbon ceramic brake disc is 12.8 mm / 0.5 inches larger than the M Compound brake disc at 88.8 mm / 3.5 inches. M Carbon ceramic brake, friction surface width Index Explanation A M Compound friction surface B M Carbon ceramic friction surface 1 76.0 mm / 3.0 inches 2 88.8 mm / 3.5 inches The diameter of the M Carbon ceramic brake disc is 10 mm bigger and its thickness 2 mm greater. Courtesy of M5POST.com 13 M Carbon Ceramic Brake System 5. Comparison to M Compound Brake Index Explanation A Front M compound brake disc B Front M Carbon ceramic brake disc 1 410 mm /16.14 inches diameter, 10 mm / .39 inches larger 2 38 mm /1.5 inches thick, 2 mm / .078 inches larger 5.1.2. Brake disc hub The brake disc hub is made up of a high-strength aluminium alloy. Important information is engraved on it. This information is: • Serial number • Part number • Direction of travel • Min. weight (wear weight) • Min. thickness (wear thickness) • Week/Year of manufacture. As the Carbon ceramic friction ring is exposed to alternating temperatures during driving, it uses a floating brake disc hub with a unique connection. This allows for expansion and contraction of the friction ring. 14 Courtesy of M5POST.com M Carbon Ceramic Brake System 5. Comparison to M Compound Brake M Carbon ceramic brake, float-mounted Index Explanation 1 Friction ring connection at brake disc hub A The bolts of the friction ring connection at brake disc hub should never be removed, loosened or tightened. Courtesy of M5POST.com 15 M Carbon Ceramic Brake System 5. Comparison to M Compound Brake 5.1.3. Brake caliper/pad The front brake caliper housing corresponds to the Fix M Compound brake system. Only the contact surface (1) at the swivel bearing is machined 5 mm less than for the M Compound brake caliper as the front M carbon ceramic brake disc has a 5 mm larger radius and a larger friction ring. M Carbon ceramic brake, brake caliper adaptation, front axle Index Explanation A Front M compound brake caliper B Front M Carbon ceramic brake caliper 1 Contact surface at swivel bearing, 5 mm taller The size of the brake pad friction surface is adapted to the larger friction surface of the front brake disc. CSl — M Carbon ceramic brake, brake pad, front axle Due to the 2 mm thicker brake disc, the thickness of each brake pad is reduced by 1 mm. 16 Courtesy of M5POST.com M Carbon Ceramic Brake System 5. Comparison to M Compound Brake a N 9 CM M Carbon ceramic brake, brake pad, front axle Index Explanation A M Compound brake pad B M Carbon ceramic brake pad Due to the larger brake pads the weight of the front brake caliper including the pads is 0.4 kg / 0.88 lbs heaver than the M Compound brake caliper. 5.2. Rear Axle Brake 5.2.1. Brake disc The rear M Carbon ceramic brake disc has the same diameter as the M Compound brake disc. The brake disc is 2 mm / .078 inches thicker. Similar to the front brake disc, the Carbon ceramic friction ring is float-mounted at the brake disc hub using a specific connection. 5.2.2. Brake disc hub This brake disc hub is also made from a high-strength aluminium alloy and the same information as for the front brake disc applies. • Serial number • Part number • Direction of travel • Min. weight (wear weight) • Min. thickness • Week/Year of manufacture. Courtesy of M5POST.com 17 M Carbon Ceramic Brake System 5. Comparison to M Compound Brake Sf M Carbon ceramic brake, rear axle 5.2.3. Brake caliper/pad The rear brake caliper is identical to the M Compound brake caliper, the size of the brake pads are also the same. 18 Courtesy of M5POST.com 12*02 M Carbon Ceramic Brake System 5. Comparison to M Compound Brake M Carbon ceramic brake, brake caliper, rear axle Index Explanation A Rear M compound brake caliper (Blue) B Rear M Carbon ceramic brake caliper (Gold) Due to the 2 mm thicker brake disc, the thickness of each brake pad is reduced by 1 mm. M Carbon ceramic brake, brake pad, rear axle Index Explanation A Rear M Compound brake pads B Rear M Carbon ceramic brake pads 1 Pad thickness difference 2x-1 mm, i.e. total of-2 mm 5.3. Brake Booster The brake booster is specifically designed for the increased coefficient of friction of the M Carbon ceramic brake. This is why it has its own part number. Without this adaptation, the behavior of the M Carbon ceramic brakes would be rated as disproportionately aggressive. Courtesy of M5POST.com 19 M Carbon Ceramic Brake System 6. Service Information 6.1. General Information Every impact and collision with hard materials can cause damage to the ceramic surfaces and edges. Chipping (1) of the disc surface may mean the brake disc is no longer suitable for installation and driving. Max permissible width/depth of chip = 2 mm Max permissible length = 10 mm As a result, a professional check of the brake discs for visible damage must be performed during inspection and servicing. Damage may also occur during driving by stone chipping or accident. If any of the wear indicators (2) on the disc surface are worn greater than 50% of the entire area, the disc requires replacement. For more information about assessing the Carbon Ceramic brakes (C/SiC) for wear, Refer to ISTA 34 11 667. 20 M Carbon Ceramic Brake System 6. Service Information Index Explanation 1 Chipping after accident 2 Wear indicator after racing-style continuous load or high mileage A Each time for performing the check, in the event of uncertainty or assumed borderline values as a result of damage and for necessary work, the current information and specifications in the documents in the Integrated Service Technical Application must be observed and, if necessary, a PuMA case created. No machining can be made to the brake disc surfaces. The bolts of the friction ring connection at brake disc hub should never be removed, loosened or tightened. 21 M Carbon Ceramic Brake System 6. Service Information 6.2. Dismantling/lnstallation During dismantling/installation of the brake disc there is a risk that the wheel rim or add-on parts such as brake caliper, brake pads, heat shield, mounting tools, etc. may cause chipping on the ceramic through contact. For dismantling and installation of the wheel the use of a jack or tire lifting device is the preferred method. Tire lifting device 22 Courtesy of M5POST.com M Carbon Ceramic Brake System 6. Service Information M Carbon ceramic brake, tire lifting devices f- Index Explanation A Tire lifting device 81 25 0 392 908 B Tire lifting device 81 25 0 301 746 23 M Carbon Ceramic Brake System 6. Service Information Index Explanation 1 Special tool 34 1 050 The brake pads must have the maximum spreading distance and can only be opened using the BMW special tool (no other tools). The brake caliper must be removed and installed carefully and without contact with the M Carbon ceramic brake disc. After dismantling the brake caliper must be secured with a suitable tool away from the brake disc. 24 M Carbon Ceramic Brake System 6. Service Information S hook for supporting caliper. During removal/installation there must be no force applied to the brake disc. The brake disc should only be set down on the hub side, never place the surface of the disc on a work bench or floor. A brake disc which has been dropped or experiences a heavy impact can no longer be used. The brake disc is no longer to be used due to visible and invisible damage. For cleaning the M Carbon ceramic brake no brake cleaner or safety cleaner can be used as it has an aggressive effect on the friction ring. Alcohol can be used as an alternative for cleaning when a brake has cooled down to room temperature. A_ Do not use any brake cleaner or safety cleaner! If no wheel is mounted, extra caution against contact must be taken. The brake disc should be protected against external hazards using suitable measures. Transport of the brake discs from the parts counter to the workbay should always be done in the original packaging. If no original packaging is available for transporting a brake disc, the brake disc must be properly packed to protect the disc from collision and damage. 25 M Carbon Ceramic Brake System 6. Service Information 6.3. Breaking in New Brake Pads/discs After completing repair work: • Perform functional check on brake test stand to ensure compliance with statutory guidelines. • Carry out test braking while driving at low speed, the effectiveness of the brakes may be reduced during the initial braking operation. • Brake pads do not have the optimal wear and contact pattern before approx. 1000 km / 600 miles. Drive cautiously during this period. • Advise the customer not to perform any drastic braking in the first 200 km /120 miles after brake replacement. Refer to ISTA group 34 for additional information. 26 M Carbon Ceramic Brake System 7. Sample Boundary Catalog 7.1. General Information BMW has developed a catalog to assess the appearance of new Carbon Ceramic Brake Discs. This document describes in detail what is considered normal and abnormal appearance of these new discs. Please refer to ISTA group 34 to view the Sample Boundary Catalog. 27 Bayerische Motorenwerke Aktiengesellschaft Qualifizierung und Training RontgenstraBe 7 85716 UnterschleiBheim, Germany