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Pad And Rotor Bedding Procedure

 
 
 
 
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Old 09-15-2007, 06:17 PM
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Default Pad And Rotor Bedding Procedure

Pad and Rotor Bedding Procedure for Street Performance Pads

After installing rotors and pads on a vehicle, a bedding or bed-in procedure must be performed on the brake system.

There are two objectives for bedding-in performance brakes. First, heating up the brake rotors and pads in a recommended manner, so as to promote the transfer of an even or uniform layer of pad material onto the new rotor discs; and the maturing the pad material, so that the resins used to bind and form them during manufacturing are ‘cooked-off’ the pads.

The first objective is achieved by performing a series of stops, so that the brake rotor discs and pads are heated steadily to a temperature that promotes the transfer of pad material onto the brake rotor’s friction surfaces.

It should be noted here that there is one pitfall in this process, which must be avoided. The rotor and, therefore, the vehicle should not be brought to a complete stop, with the brakes still applied, as this risks the non-uniform transfer of pad material onto the friction surfaces. This uneven transfer is sometimes known as “pad-imprinting”.

The second objective is achieved by performing another set of braking events whereby the bonding resins are “cooked-off” relatively slowly to avoid both fade and uneven deposits or thickness variations (TV) onto the rotor discs.

The bed-in process is not complete until both sets of stops have been performed.

Plan where and when you do this procedure with care and concern for others’ safety and yourself. After the last stop, the system should be allowed to cool to ambient temperature.

If you come to a complete stop before the break-in process is completed there is the chance for non-uniform pad material transfer or pad imprinting to take place and the results will be what the whole process is trying to avoid.

1. Perform five partial braking actions, from 55-60mph down to 10mph. Each event should achieve a moderate-to-high deceleration.

In terms of stopping force or severity to use depends on the vehicle. If the vehicle is equipped with an ABS system and the stopping forces exceeds approximately 0.9G’s, the ABS system will typically intervene.

What you want to accomplish is stopping at a rate below the ABS system triggering or around 0.7G’s and these events should be made one after the other, without allowing the brakes to cool other than under normal acceleration in between each stop. Remember, this is not a race so, take your time.

Depending on the composition of the pad material, the brake friction will seem to gain slightly in performance, and will then lose or fade somewhat by around the fifth stop.

You may begin to smell the pads at around the 4th to 5th stop. This odor is green fade, and is characteristic of immature or ‘green’ pads, in which the resins still need to be “cooked-off” the pad material. This odor should diminish before the last stop.

These first sets of stops, in the bed-in process, are only complete when all stops have been performed - not before.

2. After the first bed-in procedure, allow the brakes to cool by driving the vehicle at a safe speed for the conditions, without bringing the vehicle to a complete stop.

After cooling, a second set of partial braking events should be performed, followed by another cooling exercise. In some situations, a third set is beneficial, but two are normally sufficient. Again, these final sets of braking events are used to mature the pads.

Close inspection of properly bedded pads will show an area about 1/8" deep of a powdery gray area becoming visible on the edges of the pad’s friction face. This is where the paint and resins are cooking-off.

Depending on the pad compound, easy use of the brakes for an extended period of time may also lead to the removal of the bedded transfer layers on the discs by the ordinary abrasive action of the pads. Exercising the brake systems with a partial re-bedding will prevent uneven pick-up when a vehicle has seen easy braking use for a while.

After the “break-in” is complete, you should verify that the wheel lug nuts are still torqued to 90 ft. lbs.
 
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Old 09-27-2007, 11:20 AM
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Originally Posted by Whitmore View Post
Pad and Rotor Bedding Procedure for Street Performance Pads


It should be noted here that there is one pitfall in this process, which must be avoided. The rotor and, therefore, the vehicle should not be brought to a complete stop, with the brakes still applied, as this risks the non-uniform transfer of pad material onto the friction surfaces. This uneven transfer is sometimes known as “pad-imprinting”.

this step is CRUCIAL and can not be over looked.
 

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