Brake Bedding a cure for Brake Judder?

*Squid* · 01-19-2005, 12:12 PM

Brake pad glazing is caused when the brake pad friction material is overheated.
This results in crystallized friction material on the pad surface and the brake disc.
Typical symptoms of glazed brake pads include: Poor stopping performance, vibration or brake judder, and cracks or fissures in the brake pad material.
Pad glazing is typically caused by operating the brake pads at a temperature above the specified temperature range of the friction material or not properly following the 'Bedding-in' instructions for the brake pads. Always follow the manufacturers brake pad bedding-in instructions and use a brake pad that has a temperature range that is sufficient for its intended use.

And this is bedding in :

For optimal use of any given brake system, the pads and rotor have to be compatible with each other. The bed-in procedure establishes that compatibility between the pad and rotor. This is achieved by a combination of rubbing speed, temperature, line pressure, and Inertia. Bed-in is also influenced by pad and rotor material chemistries. It is always recommended that only compatible pads and rotors be used in any given application.
Bedding in advantages:
1. Gradually heat treats the rotor and eliminates any thermal shock in the rotor.
2. Burn off volatiles and moisture from the resin that is near pad surface.
This will eliminate “green fade.”
3. Establish a layer of transfer film about a few microns thick on the rotor surface. Shearing of the film during friction is an effective source of friction force. Otherwise, when using a freshly ground rotor without the transfer film, the main friction force would come from cutting, plowing, or scoring the asperities on the rotor surface. This leads to inconsistent braking effectiveness.
4. Mate the two surfaces to a near perfect geometrical match, so that the contact area is high, and therefore the friction force is increased.
5. The performance of a fresh rotor/fresh pad system would be inconsistent. This is due to ever-changing structures and properties of the two mating materials. Bed-in of pads and rotor will form a stable transfer film.
6. If bedding in procedure is not applied, a stable transfer film may not be established for a long time. In other words, the rotor surface would have to be constantly regenerating a film that is not quite stable for a long time. This effect would reduce the performance and increase the wear.

*Squid* · 01-19-2005, 12:19 PM

I now have over 16,000 miles on my truck and no judder. I wonder if it's because I always perform this procedure on all my new vehicles (even motorcycles) and whenever I do a brake job.
Is it possible that some are doing this and some are not?
For stop and go driving this very important and I have a hunch that this might be part of the problem.

It would be really nice if someone who goes in for a Brake TSB would Bed their brakes in and then periodically update us as to the condition of their brakes.

It would be even better if it was someone who has had the TSB already done at least once.

Bed In Procedure

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.

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.

By the way you can do a search on the internet or call a local brake shop to verify that this Info is legit.

logicjunky · 01-19-2005, 12:19 PM

So, I saw this first and I will ask the inevitable questions, Squid:

1) Where do we find the manufacturer's instructions for 'bedding in'?

2) How do we know that our pad's composition is matched correctly to our rotor's composition?

3) Where can I get some d@mn bait? (Vegas Vacation)

Good post, interesting...hmm.

logicjunky · 01-19-2005, 12:20 PM

Quote:

Originally Posted by Squid

I now have over 16,000 miles on my truck and no judder. I wonder if it's because I always perform this procedure on all my new vehicles (even motorcycles) and whenever I do a brake job.Is it possible that the people who don't have the judder also do this and are assuming that everyone else is also?

Bed In Procedure

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.

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.

By the way you can do a search on the internet or call a local brake shop to verify that this Ifo is legit.

Haha...
I posted too fast. You didn't have that second post up yet. Thanks again, Squid!!

*Squid* · 01-19-2005, 12:39 PM

Quote:

Originally Posted by logicjunky

Haha...
I posted too fast. You didn't have that second post up yet. Thanks again, Squid!!

It's time to change your user name to Quick Draw A.S.A.P.

Geez I'm still cleaning it up.

logicjunky · 01-19-2005, 12:46 PM

Quote:

Originally Posted by Squid

It's time to change your user name to Quick Draw A.S.A.P.

Geez I'm still cleaning it up.

Actually, is there a way to change user names? I looked through the User CP section and no luck there...

*Squid* · 01-19-2005, 12:50 PM

Quote:

Originally Posted by logicjunky

Actually, is there a way to change user names? I looked through the User CP section and no luck there...

I've heard that a PM to Ekool is the only way.

Tah Dah ! Now I'm done.

Slurppie · 01-19-2005, 01:19 PM

The tech did this process on each of my 3 brake issues (per the TSB bedding process) and it hasn't done jack $h1t. It's like clockwork...every 3k - 4k miles I start having problems.

*Squid* · 01-19-2005, 01:31 PM

Quote:

Originally Posted by Slurppie

The tech did this process on each of my 3 brake issues (per the TSB bedding process) and it hasn't done jack $h1t. It's like clockwork...every 3k - 4k miles I start having problems.

May I ask if you rode with him when it was done?
Is it possible that in his hurry to make money that it wasn't?
If I bed them in myself then I know the answers to these questions.
and maybe, just maybe, thats why I still have the original Brakes after 16,000 miles?
Just a Theory.

Slurppie · 01-19-2005, 06:40 PM

Quote:

Originally Posted by Squid

May I ask if you rode with him when it was done?
Is it possible that in his hurry to make money that it wasn't?
If I bed them in myself then I know the answers to these questions.
and maybe, just maybe, thats why I still have the original Brakes after 16,000 miles?
Just a Theory.

Who are you to ask if I rode with him? Just kidding, no i watched him do the bedding on a road behind the dealership, which also racks up several miles each time.

*Squid* · 01-20-2005, 12:58 AM

Quote:

Originally Posted by Slurppie

Who are you to ask if I rode with him? Just kidding, no i watched him do the bedding on a road behind the dealership, which also racks up several miles each time.

So much for my theory. Thanks

HavockWK · 01-20-2005, 07:52 AM

Quote:

Originally Posted by Squid

May I ask if you rode with him when it was done?
Is it possible that in his hurry to make money that it wasn't?
If I bed them in myself then I know the answers to these questions.
and maybe, just maybe, thats why I still have the original Brakes after 16,000 miles?
Just a Theory.

This is the first I have heard of bedding the brakes. Seems like this is a natural process that occurs through routine driving and the above instructions just try to hurry it along. I don't know, just seems logical. Yes, the pads need a little time to get broken in to get a good working surface with the rotors, I don't deny that. I know when I replace the brake pads, I do some testing to make sure it will stop without problems, but I don't over heat the brakes like this says. This process seems a little extreme to me since I know people who do their own pad replacements (non-Titans) and don't follow this procedure and don't have any subsequent issues.

As for my Titan, I have 14K miles since it was built a year ago and have no brake problems. I have never had a brake job and have not bedded the brakes, so I think you and I are just part of the lucky "no-judder" crew.

KenedyTXTitan · 01-20-2005, 05:28 PM

Is the judder a 2wd or 4wd problem?? Are the rotors any different for 2 or 4x4??

*Squid* · 01-20-2005, 05:35 PM

Quote:

Originally Posted by KenedyTXTitan

Is the judder a 2wd or 4wd problem?? Are the rotors any different for 2 or 4x4??

It's applicable to every Titan on the road. Some get it. Some don't.
So far there are no hard facts to explain it. Just a lot of theories, and finger pointing.

Quad T · 01-21-2005, 08:48 AM

Quote:

Originally Posted by HavockWK

This is the first I have heard of bedding the brakes. Seems like this is a natural process that occurs through routine driving and the above instructions just try to hurry it along. I don't know, just seems logical.

Actually, normal driving is not going to get the job done. The pad and the rotor are never going to be given the opportunity to go through such important molecular changes. This bedding in process is something I know a thing or two about because it can be the difference between life and death on the race track.

Ironically enough in my circle of friends we sort of joke about bedding pads all the time because we call it "smoking them", as in "hey, want to get together and smoke some pads?"

Normal driving is not going to produce these kinds of effects, and with race pads that operate at temps exceeding 1,200 degrees they often display billows of smoke when being bedded because their operating temps are so much higher than street pads. And if that is not cool enough, some pads throw sparks the first one or two times they are used because the pad material has such a high concentration of metals.

Bottom line – I not only bed my track pads, I always bed my street pads.