Bedding in brakes is a critical step after install and will greatly impact performance and longevity. Do it right with this process.
Like many components, brake pads and rotors need to be broken in for these parts to work together well and for a long time. This process is called bedding in. All brake pads and rotors must be bedded in together to maximize brake performance.
Simply stated, the bedding-in process is one of gradually building up heat in the pads and rotors. This process lays down a thin layer of brake pad material, a film, on the surface of the rotor. Laying down this thin film helps minimize brake judder.
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Brake judder is the vibration when the brakes are applied. This vibration can be so minute that is it not noticeable, or it can be a very distinguishable shudder that is felt through the brake pedal or steering wheel. Following the manufacturer’s bed-in procedures will ensure that a smooth, even layer of transfer film on the rotor will exist to combat the judder.
To bed-in new brake pads properly, the brake rotors should be new or resurfaced. The old transfer film from the previous pads need to be removed so the compound from the new brake pads provides the material for the transfer film. Before resurfacing rotors, check for excessive run-out with a dial indicator gauge before sending it out to be resurfaced.
Brake rotors that are not bedded in properly, or overheated, can cause a judder when the brakes are applied. A judder can be slight enough to be unnoticeable or severe enough to be a distraction. A judder generated in the front brakes can often be felt in the steering wheel.
It is strongly encouraged to use the bed-in procedure from the manufacturer of the brake pads and rotor that you are using. This keeps you in warranty compliance and will ensure a long, trouble-free life of the brake components. Below is a generic procedure for bedding in brake pads and rotors for all pad compounds. This is the bare minimum and should be followed if no procedure is included in the kit you have purchased.
The single most improved area in the brake systems over the past 50 years has been in the brake pad material. Organic brake pads are composed of fibers such as glass, fiber, rubber, carbon, and Kevlar mixed with binding resins to hold them together. Semimetallic pads contain a percentage of steel, iron, or copper combined with friction modifiers and fillers. Ceramic pads are composed of a dense ceramic material with copper fibers.
After the brake system has been installed and tested as discussed above, the bedding-in procedure can be initiated. The procedure should be undertaken on a closed track or safe roadway where speeds of 65 mph can be legally obtained, followed by a rapid deceleration without posing a safety risk.
Start with a short series of very light decelerations to bring the heat up in the brake pads and rotors. Most professionals recommend to apply the brakes for 3 to 5 seconds and release the pedal for 6 to 10 seconds before applying the brakes again. Some professionals use a vocal count of 5 on the brakes with a count of 10 off for a cycle to allow the heat to sink into the pads and rotor.
After several cycles of light stops, the brakes should begin to warm sufficiently to continue with a series of medium to firm braking cycles to continue raising the heat level in the brakes.
The bedding-in cycle can then continue with 8 to 10 hard decelerations from highway speeds of 55 to 65 mph down to 25 mph. Use the same amount of time to release the braking and allow the heat-sinking process to continue between cycles. The pads should have a positive and consistent feel during braking. If any brake fade is noticed during the bed-in cycles, begin the cool-down process immediately.
From here you can drive at a moderate speed, using the brakes minimally, until most of the heat has dissipated from the brakes. Park the vehicle and allow the brakes to cool down to ambient air temperature. For street vehicles, the bedding-in process is complete.
Cooling vanes vary in size and shape depending on the manufacturer and the application the rotors are designed for. These cooling vanes are often the best method of controlling brake fade.
For track-only vehicles with brake cooling ducts, turning off the cooling fans or blocking the ducts will allow the pads and rotors to heat up quicker and speed up the bedding-in process. For race vehicles, always get heat into the brakes prior to each event. This will help to ensure best consistency, performance, and durability from your brakes.
Post Bedding-In Inspection
After the bedding-in procedure has been accomplished, the rotors should have a burnished finish across the rotor face. Look for any splotching that would signify that the brakes were brought up to temperature too quickly in the bedding-in process.
If the brakes begin to exhibit noticeable brake judder, the rotors may need to be resurfaced and the bedding-in process accomplished again to restore a transfer film to the uniform surface of the rotor.
Written by Bobby Kimbrough and republished with permission by CarTech Inc.
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