100 Miles And Feels Like Bad Rotors

[nycmikie]

HEY DAVE
Did the bedding 7:30 am today man i must be nuts lol i thought i would do it on the pkwy before to many people get up and i still want to throw my guts up from this bedding thing lol but any way after i did it i must say it feels smooth just want to try it out on monday morning to see if its still smooth and thanks for the guy that was thinking i was feeling the anti-lock but i have worked on many cars in my life and i know how to go fast iam just not up to date on the very new cars like i said to me it felt like a bad rotor or 2 in the back if this works i rather nobody touch the car at all.
then i decided to come to a dead stop and shut the traction control and flat punch the car from a idle WOWWWWWWWWWWWW has no problem blowing the tires away with a 2.80 gear i did not think for a second the car had all that power in it.
check out my website you will like my camaro and i did own a 70 superbee
www.hotrodmechanic.net

[FirstChrysler]

Originally Posted by nycmikie

Man i love my new 2006 300c but when i had to apply the brakes hard it feels like the rear rotors are bad it starts to vibrate in rear of the car and when i test drove a new 2006 touring it did the same thing but worse! so anybody else with this rotor problem?

I had this problem when I first got my 300C. I was concerned and came to this forum for help. I read the brake bedding post, but never got around to doing it (I'm happy to hear it is working for you). I figured I would have the dealer check it out at the first oil change and if there is a problem to have it fixed under warranty.

Well, I am at 3000 km now and I no longer have this problem. The problem went away by itself. My guess is that all my city driving may have somewhat "bedded" the brakes (but I am no mechanic). My car was sitting on my dealers lot for a while (built in August 05 and I picked it up at the end of December), so perhaps all that sitting without driving was the cause of the problem (or perhaps just a poor set of discs were used that month). What is the build date on your 300?

[nycmikie]

and the brakes now are great Thanks Dave cant believe it worked now with a 190 miles on the car all seems good and this car WOWWWWWWWWWW
I LOVE IT ITS LIKE DRIVING A $70,000 DOLLAR CAR Its still blows me away how fast this car really is for a luxury car and handles so well I drove a hemi charger and it drove like a regular sport car nothing like the 300c

[DZeckhausen]

Originally Posted by FirstChrysler

I had this problem when I first got my 300C. I was concerned and came to this forum for help. I read the brake bedding post, but never got around to doing it (I'm happy to hear it is working for you). I figured I would have the dealer check it out at the first oil change and if there is a problem to have it fixed under warranty.

Well, I am at 3000 km now and I no longer have this problem. The problem went away by itself. My guess is that all my city driving may have somewhat "bedded" the brakes (but I am no mechanic). My car was sitting on my dealers lot for a while (built in August 05 and I picked it up at the end of December), so perhaps all that sitting without driving was the cause of the problem (or perhaps just a poor set of discs were used that month). What is the build date on your 300?

There's no way to bed the brakes with just normal stop-and-go driving, no matter how aggressive. At best, you can form a partial transfer layer on the rotors during a high speed panic stop. It takes repeated 60-10 threshold braking, at least a half dozen times in rapid succession, to get the rotors glowing hot enough to melt that pad layer onto the rotor surfaces.

In your case, the surface rust (from sitting 5 months on a dealer's lot) on the cast iron rotors took a while to wear off. Once that happened, the vibration went away and the brakes felt smoother. But they still aren't performing to their full potential. Remember, there are two modes of friction - abrasive and adherent. You don't get any adherent friction unless there is a transfer layer of pad material on the rotors' swept surfaces.

[illini4]

Do any technical reports from a recognized source (SAE, or a brake system manufacturer for example) exist on this subject? How was the presence of brake pad material on the rotor verified? I assume a microscope photo of a rotor cross section would be one way to do that.

[Finco]

Hi nycmikie, I had the same problem with mine. My car had 27 miles on it when I took delivery. When braking above 40 mph it felt like the rotors were bad. I called the dealer and he agreed to turn rotors but this being a new car I decided to give it alittle time.After about 500 miles pads broke-in and everything is fine. Enjoy your new 300c.

[DZeckhausen]

Originally Posted by illini4

Do any technical reports from a recognized source (SAE, or a brake system manufacturer for example) exist on this subject? How was the presence of brake pad material on the rotor verified? I assume a microscope photo of a rotor cross section would be one way to do that.

White papers from brake system manufacturer: http://www.stoptech.com/tech_info/wp_bedintheory.shtml and http://stoptech.com/tech_info/wp_warped_brakedisk.shtml

I've attended several SAE courses on brake technology and control systems, including this one: http://tinyurl.com/jh2uo that have covered the topic of brake bedding. In fact, this is where I learned about bedding changing the emissivity of the iron rotor so it slightly improves its ability to shed heat via radiation.

Bedding is not a black art or an unproven science. Most high performance brake pads now come with bedding instructions either printed on the box or on an enclosed sheet of instructions.