FastZ.com (Z06) - Burnishing Rotors and Pads

Last Updated: Tuesday, June 23, 2009
Originally Posted: Sunday, March 23, 2003

Season New Rotors and Bed New Pads (Burnishing)

Purpose

To properly prepare the braking surface for street use or track use.

Directions

Rotor Seasoning for Street or Light Track Applications
provided by Baer Brake Systems.

The first step in preparing the brake system for duty is to �SEASON� the rotors. The most visible effects are that of burning the machine oils from the surface of the iron and establishing a wear pattern between the pad and rotor. The most complex task it performs is that of relieving the internal stresses within the material. If you�ve ever poured water into a glass of ice, and noticed the ice cracking, then you�ve witnessed, first hand, the effects of internal stresses. The rotor casting and cooling processes leave the rotor with internal stresses.

By gradually heating the material, the crystalline matrix will reconfigure to relieve these internal stresses. After these stresses are relieved, the rotor is ready to accept the heat of bedding pads. Heating the rotors before they are fully seasoned can result in material deformation due to the unrelieved internal stresses in the material. This deformation may cause a vibration from the brakes. In order to prevent this vibration, all PRO-RACE+ rotors are trued before shipping.

Rotors need to be gradually elevated to �race� temperatures before any severe use. A �nibble�, or slight vibration, normally indicates rotors that were heated too quickly. After initial �Seasoning�, when running your car at open track events or serious canyon carving, you should use the first lap of a session (or first couple miles of open road), to warm the brakes as well as the engine, gearbox, etc. Where an engine turns chemical energy into motion, the brakes turn that motion into thermal energy....and lots of it! And where there is no cooling system for the brakes as there is for the engine, and there�s not, the brakes could use the courtesy of a warm-up lap.

Remember to ALWAYS WARM THE BRAKES before any heavy use!

Seasoning Procedure:

Before you begin, please note: The following represents the minimum recommended �Seasoning� process. If your situation offers any opportunity to perform gentle preliminary �Seasoning� outlined in Step 2 below for a longer period of time, this will generally render even better performance and increase further long term rotor life.
Use the vehicle for 5 to 6 days of gentle driving. Use the brakes to the same extent that you used the stock brakes, DO NOT TEST PERFORMANCE or ATTEMPT HEAVY USE UNTIL ALL ITEMS OUTLINED HAVE BEEN COMPLETED. It is imperative that excessive heat is not put into the rotors at this stage. They need temperature-cycling to relieve the internal stresses.
Note: Zinc plated rotors (which are an extra cost option) need a couple of extra days of driving to wear through the plating before �Seasoning� actually will begin.
Find a safe location where the brakes can be run to temperature.
- Your goal is to gradually increase brake temperatures with progressively faster stops. Start by performing four 60 to 70 mph stops, as you would in the normal course of driving.
- Next, perform four medium effort partial stops (about 50 %) from 60 mph down to 15 mph. Follow this with five minutes of freeway driving with LITTLE to NO BRAKING to allow the rotors to cool.
- Then, perform four medium-hard effort partial stops (about 75 %) from 60 mph down to 15 mph. Follow this with ten minutes of freeway driving with LITTLE to NO BRAKING to allow the rotors to cool.
- Park the car and allow the brakes to cool overnight to ambient temperature. You are now 50 % done with the rotor �Seasoning/Bedding� procedure, proceed to STEP 4 the following day.
Return to the safe location where the brakes can be run to temperature.
- Make sure the brakes are warmed to full operating temperature and then, perform four medium effort partial stops (about 50 %) from 60 mph down to 15 mph. Follow this with five minutes of freeway driving with LITTLE to NO BRAKING to allow the rotors to cool.
- Then, perform four medium-hard effort partial stops (about 75 %) from 60 mph down to 15 mph. Follow this with ten minutes of freeway driving with LITTLE to NO BRAKING to allow the rotors to cool.
- NOW, make six HARD partial stops from 60+ mph down to 15 mph or until rotors have reached an operation temperature of between 900 and 1,100� (Note: Temperature paints to accurately measure rotor temperature may be purchased from Baer Racing). Every effort should be made to perform this procedure without locking a wheel. Follow this with ten minutes of freeway driving with LITTLE to NO BRAKING to allow the rotors to cool.
Let the system cool off over night. The rotors are then ready for the next step in Preparing your Brake System: Bedding Pads.

Pad Bedding for Street or Light Track Applications

provided by Baer Brake Systems.

Bedding brake pads has a couple of important effects. The friction material in semi-metallic pads is held together by an organic binder, usually a type of phenolic material. As the pads get hot, the binder boils, and burns, from the top surface of the pad. Once this burning or �Bedding� takes place the friction material makes proper contact with the rotor.

Some race/performance pads, like the Performance Friction�s line of pads, are designated as �pre-burnished� from the manufacturer. In our experience these pads still benefit from�bedding�. �Bedding� pads establishes a wear pattern between the pads and rotor. Some pads, like the Performance Friction pads, deposit a layer of carbon in the surface of the rotor. They need that layer of carbon to perform at peak efficiency.

Most Baer Claw� systems which are equipped with PBR calipers, SS/DRAG, SPORT, TRACK, and TRACK+, come standard with metallic pads. However, PBR based A-SEDAN systems, as well as PRO-RACE and PRO-RACE+ Systems with the Alcon calipers feature carbon metallic pads from either Pagid, Performance Friction or Tekstar.

Bedding Metallic or Carbon/Metallic Pads - (NEVER DRAG the brakes)

Note: Never �Bed� pads on rotors which have not first been �Seasoned.� Always allow a substantial coast down zone when bedding pads that will allow you to safely drive the car to a stop in the event of fade.
Perform four repeated light to medium stops, from 65 to 10 mph, to bring the rotors to temperature.
Perform two heavy stops, back to back, at a point just pending wheel lock, from 65 mph to about 5 mph.
Drive for five to ten minutes to create cooling airflow, without using the brakes if at all possible.
Perform three light stops in succession.
Perform eight heavy stops, back to back, at a point just pending wheel lock, from 65 mph to about 5 mph.
Drive for ten minutes to create cooling airflow, without using the brakes if at all possible.

Metallic brake pads need high temperatures to keep the pad �Bedded�. If you drive the car for a period of time without using the brakes extensively, you may need to �Bed� the pads again. This is not a problem. Simply repeat the procedure.

When switching from Performance Friction Carbon Metallic pads to semi-metallic brake pads (something we do not recommend), you will need to wear through the layer of carbon that the PFC pads have deposited in the rotor surface. The new pads won�t grip well at all, until this layer of carbon is removed.

Racers should �Bed� a few sets of pads at a time. In the event you need to change brake pads during a race, you MUST use a set of �Bedded� pads. Racing on �non-bedded� pads leads to a type of �fade� caused by the binding agents coming out of the pad too quickly. This is called �green fade�. These binders may create a liquid (actually a gas) layer between your pads and rotors. Liquids have a very poor coefficient of friction. This condition is the reason for reverse slotting or crossdrilling rotors, as it allows a pathway for the gasses to escape.

Rotor Seasoning for Race Applications
provided by Baer Brake Systems.

The first step in preparing the brake system for duty is to �SEASON� the rotors. The most visible effects are that of burning the machine oils from the surface of the iron and establishing a wear pattern between the pad and rotor. The most complex task it performs is that of relieving the internal stresses within the material. If you�ve ever poured water into a glass of ice, and noticed the ice cracking, then you�ve witnessed, first hand, the effects of internal stresses. The rotor casting and cooling processes leave the rotor with internal stresses.

By gradually heating the material, the crystalline matrix will reconfigure to relieve these internal stresses. After these stresses are relieved, the rotor is ready to accept the heat of bedding pads. Heating the rotors before they are fully seasoned can result in material deformation due to the unrelieved internal stresses in the material. This deformation may cause a vibration from the brakes. In order to prevent this vibration, all PRO-RACE+ rotors are trued before shipping.

Rotors need to be gradually elevated to �race� temperatures before any severe use. A �nibble�, or slight vibration, normally indicates rotors that were heated too quickly.

After initial �Seasoning�, when running your car at open track events or serious canyon carving, you should use the first lap of a session (or first couple miles of open road), to warm the brakes as well as the engine, gearbox, etc. Where an engine turns chemical energy into motion, the brakes turn that motion into thermal energy....and lots of it! And where there is no cooling system for the brakes as there is for the engine, and there�s not, the brakes could use the courtesy of a warm-up lap.

Remember to ALWAYS WARM THE BRAKES before any heavy use!

Seasoning procedure

Before you begin, please note: The following is a condensed version of of the Seasoning process designed for racing, where rotors are often replaced after every event. If your situation offers any opportunity to perform the Seasoning for Street & Track outlined on a separate instruction set, please do so. The most noticeable result of which will be dramatically increased long term rotor life.
Temporarily close any cooling ducts provided for the brakes. Note: New rotors should be �Seasoned� with used pads. If you are �Seasoning� a completely new system, this is not an alternative. Take extra care in the �Seasoning�� procedure. Most likely, you will begin �bedding� the pads in the latter stages of the procedure. It is still recommended that you follow the 'Bedding Pads' procedures.
Make several light stops from 30 mph to ensure brake system is functioning properly.
Gradually increase brake temperatures with progressively harder, faster, stops.
Continue the process, through 10-15 stops, until the rotors have reached full operational temperature; about 1100�F.
Note: Accurate temperature paints may be obtained from Baer Racing.
Allow the brakes to cool, slowly, by driving easily for 10 minutes or so. The idea is to cool the brake system to ambient. Given the opportunity, let the system cool off over night.
The rotors are now ready for the next step in Preparing your Brake System, bedding pads

Racers should �Season� a couple sets of rotors at the same time. In the event that one needs to be replaced during a race, it should be replaced with a�Seasoned� rotor. We strongly advise against racing on a �green� rotor. The thermal shock and unrelieved internal stresses can crack, or even break, a �green� rotor.

Additionally, race cars should run a cool down lap before parking a car that has been run at speed. In the pits it is advised to roll the car back and forth, when the brakes are hot, to avoid internal stresses from uneven cooling of the rotor.

To avoid the expense of using valuable track time to �Season� rotors, Baer Racing offers �Pre-Seasoned� rotors (2 pc rotors only).

Pad Bedding for Race Applications
provided by Baer Brake Systems.

Bedding brake pads has a couple of important effects. The friction material in semi-metallic pads is held together by an organic binder, usually a type of phenolic material. As the pads get hot, the binder boils, and burns, from the top surface of the pad. Once this burning or �Bedding� takes place the friction material makes proper contact with the rotor.

Some race/performance pads, like the Performance Friction�s line of pads, are designated as �pre-burnished� from the manufacturer. In our experience these pads still benefit from�bedding�. �Bedding� pads establishes a wear pattern between the pads and rotor. Some pads, like the Performance Friction pads, deposit a layer of carbon in the surface of the rotor. They need that layer of carbon to perform at peak efficiency.

Most Baer Claw� systems which are equipped with PBR calipers, SS/DRAG, SPORT, TRACK, and TRACK+, come standard with metallic pads. However, PBR based A-SEDAN systems, as well as PRO-RACE and PRO-RACE+ Systems with the Alcon calipers feature carbon metallic pads from either Pagid, Performance Friction or Tekstar.

Bedding Metallic or Carbon/Metallic Pads

Note: Never �Bed� pads on rotors which have not first been �Seasoned�. Always allow a substantial coast down zone when bedding pads that will allow you to safely drive the car to a stop in the event of fade. Never Drag the Brakes.

Perform four repeated light to medium stops, from 65 to 10 mph, to bring the rotors to temperature.
Perform two heavy stops, back to back, at a point just pending wheel lock, from 65 mph to about 5 mph.
Drive for five to ten minutes to create cooling airflow, without using the brakes if at all possible.
Perform three light stops in succession.
Perform eight heavy stops, back to back, at a point just pending wheel lock, from 65 mph to about 5 mph.
Drive for ten minutes to create cooling airflow, without using the brakes if at all possible.

Metallic brake pads need high temperatures to keep the pad �Bedded�. If you drive the car for a period of time without using the brakes extensively, you may need to �Bed� the pads again. This is not a problem. Simply repeat the procedure.

When switching from Performance Friction Carbon Metallic pads to semi-metallic brake pads (something we do not recommend), you will need to wear through the layer of carbon that the carbon/metal pads have deposited in the rotor surface. The new pads won�t grip well at all, until this layer of carbon is removed.

Racers should �Bed� a few sets of pads at a time. In the event you need to change brake pads during a race, you MUST use a set of �Bedded� pads. Racing on �non-bedded� pads leads to a type of �fade� caused by the binding agents coming out of the pad too quickly. This is called �green fade�. These binders may create a liquid (actually a gas) layer between your pads and rotors. Liquids have a very poor coefficient of friction. This condition is the reason for reverse slotting or crossdrilling rotors, as it allows a pathway for the gasses to escape.

Burnishing Pads and Rotors
provided by 2002 Helms GM Service Manual page 5-70.

Caution: Road test a vehicle under safe conditions and while obeying all traffic laws. Do not attempt any maneuvers that could jeopardize vehicle control. Failure to adhere to these precautions could lead to serious personal injury and vehicle damage.

Burnishing the brake pads and brake rotors is necessary in order to ensure that the braking surfaces are properly prepared after service has been performed on the disc brake system.

This procedure should be performed whenever the disc brake rotors have been refinished or replaced, and/or whenever the disc brake pads have been replaced.
1. Select a smooth road with little or no traffic.
2. Accelerate the vehicle to 48 km/h (30 mph).
Important: Use care to avoid overheating the brakes while performing this step.
3. Using moderate to firm pressure, apply the brakes to bring the vehicle to a stop. Do not allow the brakes to lock.
4. Repeat steps 2 and 3 until approximately 20 stops have been completed. Allow sufficient cooling periods between stops in order to properly burnish the brake pads and rotors.