"bed" or "seat" new front brake pads?

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I will be replacing my front brake pads this afternoon, and after searching the archives for install info, I see some have said you need to "bed" or "seat" the new pads once installed. Can someone clue me in on this? I couldnt find any procedure on doing this or why this needs to be done. From the sounds of it, this will be a super easy job, although I am wondering how people are removing fluid from the MC so it doesnt overflow when you compress the caliper? I read you could attach a hose to the bleeder valve which may be easier, but wouldnt that then require you to bleed the system when finished? Thanks in advance for the advice. This site rules.
 
Montana Cruiser said:
I will be replacing my front brake pads this afternoon, and after searching the archives for install info, I see some have said you need to "bed" or "seat" the new pads once installed. Can someone clue me in on this? I couldnt find any procedure on doing this or why this needs to be done. From the sounds of it, this will be a super easy job, although I am wondering how people are removing fluid from the MC so it doesnt overflow when you compress the caliper? I read you could attach a hose to the bleeder valve which may be easier, but wouldnt that then require you to bleed the system when finished? Thanks in advance for the advice. This site rules.

Haven't seen the "bed" and "seat" thing, but I just follow the procedure in the FSM.

On removing the brake fluid, just remove the reservour cap, grab the little plastic cup inside the reservoir and bail out a few cups worth... no biggy. Once you done, check the fluid level and add if necessary.

:beer:
Rookie2
 
One piece of advice I had seen (not sure if it was on mud, 80cool or something else) suggested the following:

- Find a loooooonnnnggg stretch of road
- Drive at 50-60mph
- Apply firm pressure (not an emergency stop) to slow the truck, but not to stop it (ie to say 10mph)
- Accelerate back to 50-60mph
- repeat process 3-5x

- This is all from memory, so you may want to look around a bit, but this is wat I remember when I asked a similar question some time ago.

Cheers, Hugh
 
On the StopTech web site, look for a white paper about "myths" of warped rotors and brake judder. There's some good info on break-in procedures.

LT
 
"If you've just installed a big brake kit or even if you've only changed your brake pads and rotors, you should "bed" them in by following the instructions below. Proper bedding of brakes will improve pedal feel, reduce or eliminate brake squeal, and extend the life of your pads and rotors. Because bedding increases the emissivity of the rotors, it even allows them to shed more heat via radiation, making them run cooler.

Caution: When you've just installed new pads/rotors or a big brake kit, the first few applications of the brake pedal will result in almost no braking power. Gently apply the brakes a few times at low speed in order to build up some grip before blasting down the road at high speed. Otherwise, you may be in for a nasty surprise the first time you hit the brakes at 60 mph.

When following these instructions, please avoid doing it in the presence of other vehicles. Breaking in your new pads and rotors is often best done very early in the morning, since other drivers will have no idea what you are up to and will respond in a variety of ways ranging from fear to curiosity to aggression. And an officer of the law will probably not understand when you try to explain why you were driving erratically! Zeckhausen Racing does not endorse speeding on public roads and takes no responsibility for any injuries or tickets you may receive while following these instructions.

From a speed of about 60mph, gently apply the brakes to slow the car down to about 45mph, then accelerate back up to 60mph and repeat. Do this about four or five times to bring the brakes up to operating temperature. This prevents you from thermally shocking the rotors and pads in the next steps.

Make a series of eight near-stops from 60 to about 10 mph. Do it HARD by pressing on the brakes firmly, just shy of locking the wheels or engaging ABS. At the end of each slowdown, immediately accelerate back to 60mph. DO NOT COME TO A COMPLETE STOP! (Note: With less aggressive street pads and/or stock brake calipers, you may need to do this fewer times. If your pedal gets soft or you feel the brakes going away, then you've done enough. Proceed to the next step.)

During this process, you must not come to a complete stop because you will transfer (imprint) pad material onto the hot rotors, which can lead to vibration, uneven braking, and could even ruin the rotors.

Depending on the pads you are using, the brakes may begin to fade slightly after the 7th or 8th near-stop. This fade will stabilize, but not completely go away until the brakes have fully cooled. A bad smell from the brakes, and even some smoke, is normal.

After the 8th near-stop, accelerate back up to speed and drive around for as long as possible without using the brakes. The brakes will need at least 10 minutes to cool down. Obviously, it's OK to use the brakes to avoid an accident, but try to minimize their use until they have cooled.

If club race pads, such as Pagid Orange or Porterfield R4, are being used, add four near-stops from 80 to 10mph. If full race pads, such as Pagid Black, are being used, add four near-stops from 100 to 10 mph.

After the break-in cycle, there should be a blue tint and a light gray film on the rotor face. The blue tint tells you the rotor has reached break-in temperature and the gray film is pad material starting to transfer onto the rotor face. This is what you are looking for. The best braking occurs when there is an even layer of of pad material deposited across the face of the rotors. This minimizes squealing, increases braking torque, and maximizes pad and rotor life.

After the first break in cycle shown above, the brakes may still not be fully broken in. A second bed-in cycle, AFTER the brakes have cooled down fully from the first cycle, may be necessary before the brakes really start to perform well. If you've just installed a big brake kit, the pedal travel may not feel as firm as you expected. After the second cycle, the pedal will become noticeably firmer. "
 
From my days of sports car racing, we used to "bed" a new set of brake pads to prevent then from glazing over when used in earnest on the track. The "theory" is that the peaks of the small (and some not so small) undulations in the surface of the brake rotor will contact the fresh (flat) surface of the pad and cause intense heating in those areas, thus glazing the pad. That's the theory. In practice, I have taken a fresh set of pads out onto a track and suffered no ill effects, so perhaps the quality of pads has progressed. Nonethe less, it is traditional to "bed" a set of pads before a race. It's also a good excuse to drive your race prepared car around town...............

To "bed" a set of pads means to use them in situations other than real hard braking, i.e. normal driving situations. So for *most* of us that would mean just replace the pads and drive normally - they will "bed" themselves.
 
You should not intentionally force fluid backwards through the ABS mechanism. It is possible for corrosion in the brake lines to screw up the ABS mechanism. For this reason, open up the bleeder valve before pusing in the caliper piston.

You should flush (and therefore bleed) all of the brake fluid as a matter of course when replacing pads.
 
Man I wish I would of read this a few month ago. I had put one new rotor and brakes on the back. 3000 miles later the brake on the new rotor squeels when stopping.

Is there a way to get rid of this?

Thank you,
 
After 25K miles I've not yet needed to replace pads on my cruiser yet, so I'm not familiar with the details on the '80. But, some vehicles include anti squeal shims that go between the pads and pistons. Check to see if your are supposed to have these. You can get goop that is applied to the back of the pads that can help prevent the squeal. You can also get spray that goes on the pad itself that can help prevent the squeal. That is everything I know about keeping disc brakes that are otherwise in good condition from squealing.
 

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