Typical problems and solutions with automotive disc pads and rotors

Drive your vehicle steadily within the first 300-400 miles of road use only using the brakes violently in case of emergency. During this time use the brakes lightly and intermittently to achieve a matching between the pad and rotor which we call break in or bed in.
The speed with which perfect brake in will have occurred depends on how often the brakes are used. If you drive on a freeway or motorway and do not use your brakes for miles at a time, break in periods will be much longer. Using the brakes with caution during their early life will extend their wear life and greatly reduce the chances of rotor vibration or “shimmying” as it is known in the States. During the bed in time the pads will only contact the disc on a limited area until tiny irregularities in machining or misalignment of the pads against the rotor have been removed. You can easily see how far you have progressed with bedding in your new brakes by looking through the wheel spokes and evaluating pad contact. The rotor should look shiny and smooth across its surfaces from outside to inside in all areas of the rotor. If you have purchased EBC gold zinc or black zinc coated sport slotted rotors, all of these coatings should have been visibly removed across the entire braking area of the rotor. Break in times on European vehicles is usually considerably longer than on Asian or US built vehicles because of the design of the brake system. European vehicles use a “taller” brake pad and may tend to contact on the outer edges of the rotor first and gradually contact more towards the centre of the axle over the first few hundred miles. After you are confident that the pads and discs are perfectly mated, use the brakes on a quiet and safe road 5-6 times at medium pressure bringing the car from 60mph to 10mph. Drive the vehicle for a few miles to allow the brakes to cool and repeat this procedure. During this final break in a brake odour will almost certainly appear and this is perfectly normal. This is known as green fade where the surface resins within the pad finally cure and burn off.

This bed in procedure is for STREET driving only. For race use bed in please see notes inside the package.

A - SHIM NEEDED - 60% of brake noise problems are solved by the addition of a rubber/steel/rubber shim on the reverse of the pad known as a noise reduction shim. Since 2006 all EBC Greenstuff, Redstuff and Yellowstuff pads have been manufactured with shims.

However, if your pad set does not have such shims ask for a set of these free of charge from EBC support, fit them and reinstall pads.
B - CHAMFER - Chamfering or bevelling the edges of the friction material is now done by EBC in all production. Chamfers can eliminate noise in approximately 10% of cases. Sometimes a larger than standard chamfer may be necessary due to driving styles or conditions but seek advice from EBC technical support before attempting this modification at home.
C - DRIVING STYLE - Regular city driving with frequent and light brake applications can cause pads to glaze. If noise gradually develops in such driving conditions use the brakes 2-3 times from higher speeds to load brakes more positively on a quiet road when it is safe to do so. This has the effect of deglazing the pad surface.
D - BED-IN - Most noise problems come in the first few miles of use and pads must be given a chance to bed-in. Bed-in times are extended if rotor is not turned or surface is off-flat. Even the slightest hollow in the surface of the rotor can extend bed-in time up to 500 miles. Ask customers to run vehicle for at least 500 miles.
E - SPORT ROTORS - have been shown to run quieter in many cases than plain rotors especially the EBC sport rotor which has scraper slots and helps to deglaze the pad surface and break down harmonics.
F - DRAG - In approximately 5% of cases when new pads are installed the hydraulic pistons in the caliper are pushed back and then seize when driving the vehicle after pad fitment causing drag. This can cause noise but often also shows uneven wear on the left and right hand sides of the vehicle, or on one single pad.
G - ROTOR QUALITY - With many cheap import brake rotors now on the market a quality pad with good brake effect can actually damage the rotor by picking up small disc material particles which then act like a small machining tool on the remaining rotor surface. This is detected by looking at the pad surface and seeing silver particles within the pad which have been picked up from the brake disc. Solution is to either use EBC pads with Brake-InTM coating or to scuff the brake rotor with a scratch pad and remove the silver particles from within the pad surface then reinstall and try again.

Many good technical articles have been written about this problem which is without doubt the number one regular brake problem encountered. We will give you a short easy to understand recap.

When new brake rotors are installed it is absolutely essential that they run true. All EBC rotors are manufactured and inspected to have less than 0.002 inches (.05mm) of run out. If after your new rotors are installed they have more than this amount of run out, then there is a run out problem on your car. This can be quite easy to resolve and is usually due to one of two things. First the mounting faces where the disc locates on your vehicle must be ABSOLUTELY CLEAN and free from rust or scale which develops during the lifetime of the old rotor. Even the tiniest amount of dirt or scale can throw these run out figures to five times the factory limit. After installing the rotors and tightening them using correct procedures by tightening wheel nuts diagonally with a torque wrench (not an airgun) it is vital to take a few minutes to check rotor run out with a dial gauge and if one of these is not available by holding a screw driver firmly against a part of the caliper body and rotating the disc / rotor to listen or look for distortion. If you do not correct distortion above 0.004 inches (0.1mm) at this point you will DEFINITELY experience brake judder within a few thousand miles. The actual cause of brake judder is not this run out figure (it will be almost impossible for you to detect small run out whilst driving) but over a period of time a “thin spot” would develop on an area of the rotor caused by intermittent pad contact which is known technically as DTV (disc thickness variation). As you apply pedal pressure these thin spots will cause pulsation. If the vibration or shimmying is noticed on the steering wheel it is usually a front rotor problem. The problem is usually only ONE ROTOR not necessarily the pair. If the pulsation is noticed through the bodywork of the car, such as the seat or brake pedal, it is usually a rear rotor that is at fault.

The solution for this vibration is one of two things. 1. either replace the rotors again with new units or 2. take them to your local autoparts store and ask for them to be turned or skimmed. The smallest cut of a few thousandths is all that is needed to correct this problem. When remounting the turned or new rotors, make sure run out is carefully checked as above.

The point at which this thin spot or DTV will occur depends on how regularly or irregularly the brakes are applied. If for example you drive 50 miles to work every day and hardly touch the brakes, it could appear as quickly as 500 miles. The reason for this is that regular use of the brakes tends to wear the whole surface of the brake disc at the same time whereas driving the vehicle “off the brake” causes an intermittent contact between the pad and the high spot on the rotor wearing this high spot down and causing DTV.

The second cause of brake vibration is black spotting of the rotor which is caused by the rotor over heating and a hard spot occurring intermittently around the rotor surface. This in technical terms is the formation of cementite which is a very hard by product of cast iron (rotor material) caused by over heat and sudden cooling. If you witness black spotting the only solution is to replace the rotor or have it turned. Black spotting occurs when the rotor has either worn too thin (having been turned more than once), or by brake pads that are ineffective in balancing rotor and pad temperatures. The problem for the consumer today is that all brake pads looks the same and people rely on the expertise of the guy across the counter who sells them their brakes. The design of brake pad materials is a very exact science and the difference between a company who knows what they’re doing and one who doesn’t is a few percentage points. Brake pads need to have good “thermal conductivity” to take the heat away from the rotor, optimum “compressibility” to allow the brake system to absorb or dampen minor vibrations and optimum “scrub factor”. The latter is the ability of the pad to hone out minor surface imperfections on the rotor as they occur without wearing the rotor excessively. All three of these design criteria and a few hundred more are things that EBC Brakes specialises in. We could ramble on for hours here about how clever we are but the proof of the pudding we say is in the eating. We are confident you will have a great experience with EBC Brakes if you follow our guidelines and should you not find our products to meet your desires, we are an easy company to contact and very service oriented.