HIGH-pitch squeal, front rotor, 1/3 pedal pressure only, dealer SUCKS...HELP

[copdocpvd]

2006 300C, 14,100 miles (that number is important...)

At about 12,000 miles I started noticing an exceptionally high-pitched whine when applying the brakes GENTLY at moderate speeds (under 40 mph).

Didn't seem to happen until the brakes had warmed up a little bit (in other words, didn't happen the first few miles/stops, but after a little bit of driving), and wouldn't happen if stronger pressure was put on the brake pedal.

Stopping effectiveness didn't change, and it was a much higher pitch than the typical "brake pads are going bad" sound, so I kept an eye...er, an ear on it.

Got worse, to the point that if I was gently coming to a stop at a red-light, I'd get people looking over.

Took it to a Dodge dealership (nearest Chrysler shop is a bit of a drive, Dodge shop is 4 miles away). They had it for 4 days for that and a vibration noise at WOT in the middle of the dash. I picked the car up, and surprise surprise, neither issue was fixed.

Took another morning off work, returned the car, had to take the "head mechanic" out with me for a drive, he claimed he couldn't hear the whine, so I rolled down the windows, he still couldn't hear it, so I had him sit in the driver's side, and THEN he heard it.

They fed me a line of sh*t about "well, it's just normal metallic noise blablabla...brake pads do that blablabla...we can try and fix it but it might get worse blablabla" and I told them to make it happen.

Came back next day, their "fix" was to turn the rotors and burnish the OEM pads (which had a ton of pad material left), which they listed on the service sheet as "de-glazing."

No surprise to me, the noise is still here.

I returned again, the Service Manager has told me that because the car is over 12,000 miles (despite that I had the issue before the magic 12K number turned on the odometer), that he could change the rotors or pads or "...whatever it is you think you want, but it'll be on your dime..." He also fed me the same line of crap again about it being "metallic particles in the brake pad will do that, you probably need to just wear them in."

I looked at him and said, "oh, you mean BED THE PADS IN?"

He looked at me dumbly.

I said "you mean, brake gently to warm up the disks so as not to shock the pads and disks, then bring the car to 60 mph, brake as hard as I can, just shy of activating the ABS, all the way to just before full stop, then accellerate again, until the brakes cool down again, and repeat that about eight times, then do it at 80 MPH? Yeah, I did that, and even threw in four runs at 100mph, being absolutely certain that the brakes were completely cool before coming to a full stop so as not to risk 'burning' brake pad material onto the hot disks which can cause noise and reduce braking effectiveness."

Then I told him for the fifth time, "I really do NOT think this is a brake pad issue, my friend, I know a tiny bit about what I am talking about."

So...I look to my fellow forum members.


Experience with this specific issue?

Is it some kind of harmonic or issue with the Rotor and not the pads?

How to fix it?

Any clue on how to address it with Chrysler? (I definitely have had enough of that particular Dodge dealership)


(PS, yesterday I had an idiot pull in front of me, had to panic stop and the car stopped like I threw out ten anchors, so the brake system WORKS fine, but this high-pitched gentle-braking whine isn't symptomatic of functionality problems, but it's driving me friggin' nuts...).


Many thanks in advance for your help.


Pete

[BIG SMOOTH]

I notice the same thing here. I even re-bed my brakes after 8k miles and seems to have helped but I always wondered about it. I'm only at 13.7k miles right now. Anyone else have answers or ideas? Dave Z.?

[Fuelonempty]

EDITED, I thought it was the brembos, and they always squeal no matter what car their on.

[DZeckhausen]

Originally Posted by copdocpvd

Came back next day, their "fix" was to turn the rotors and burnish the OEM pads (which had a ton of pad material left), which they listed on the service sheet as "de-glazing."

The pads had glaze for a couple of reasons. See my comments below

I said "you mean, brake gently to warm up the disks so as not to shock the pads and disks, then bring the car to 60 mph, brake as hard as I can, just shy of activating the ABS, all the way to just before full stop, then accellerate again, until the brakes cool down again, and repeat that about eight times, then do it at 80 MPH? Yeah, I did that, and even threw in four runs at 100mph, being absolutely certain that the brakes were completely cool before coming to a full stop so as not to risk 'burning' brake pad material onto the hot disks which can cause noise and reduce braking effectiveness."

What you've done here is to combine the bedding for street pads with bedding for full race pads. It's not a case of if some is good, then more must be better. By doing the bedding at 80mph, then adding four runs at 100mph, you completely cooked those street pads. A layer of glaze formed on them and, since you don't have slotted rotors, it remained - causing the squeal at light pedal pressure and should have reduced your friction level somewhat.

Keep in mind that the energy you put into your brakes goes up with the square of the velocity. So an 80mph stop is not a 33% increase in energy over a 60mph stop. It's a 75% increase. And a 100mph stop is not a 66% increase, it is a 178% increase. (If I did the math right.)

Then I told him for the fifth time, "I really do NOT think this is a brake pad issue, my friend, I know a tiny bit about what I am talking about."

In this case, it was a pad issue.

After they deglazed the pads and turned the rotors, it became a pad & rotor issue. You've essentially gone back to square one. There is no pad transfer layer on the rotors, after they've been machined. So you need to rebed the brakes, this time only doing a series of near stops from 60mph (per: http://www.zeckhausen.com/bedding_in_brakes.htm). If the pads haven't been ruined from the abuse earlier, this should cure the noise. If it does not, then you should replace the pads.

[copdocpvd]

Originally Posted by DZeckhausen

The pads had glaze for a couple of reasons. See my comments below

What you've done here is to combine the bedding for street pads with bedding for full race pads. It's not a case of if some is good, then more must be better. By doing the bedding at 80mph, then adding four runs at 100mph, you completely cooked those street pads. A layer of glaze formed on them and, since you don't have slotted rotors, it remained - causing the squeal at light pedal pressure and should have reduced your friction level somewhat.

Keep in mind that the energy you put into your brakes goes up with the square of the velocity. So an 80mph stop is not a 33% increase in energy over a 60mph stop. It's a 75% increase. And a 100mph stop is not a 66% increase, it is a 178% increase. (If I did the math right.)

In this case, it was a pad issue.

After they deglazed the pads and turned the rotors, it became a pad & rotor issue. You've essentially gone back to square one. There is no pad transfer layer on the rotors, after they've been machined. So you need to rebed the brakes, this time only doing a series of near stops from 60mph (per: http://www.zeckhausen.com/bedding_in_brakes.htm). If the pads haven't been ruined from the abuse earlier, this should cure the noise. If it does not, then you should replace the pads.

will be my "project" tomorrow, thanks Dave.

Pete

[wgondor]

Originally Posted by DZeckhausen

The pads had glaze for a couple of reasons. See my comments below

What you've done here is to combine the bedding for street pads with bedding for full race pads. It's not a case of if some is good, then more must be better. By doing the bedding at 80mph, then adding four runs at 100mph, you completely cooked those street pads. A layer of glaze formed on them and, since you don't have slotted rotors, it remained - causing the squeal at light pedal pressure and should have reduced your friction level somewhat.

Keep in mind that the energy you put into your brakes goes up with the square of the velocity. So an 80mph stop is not a 33% increase in energy over a 60mph stop. It's a 75% increase. And a 100mph stop is not a 66% increase, it is a 178% increase. (If I did the math right.)

In this case, it was a pad issue.

After they deglazed the pads and turned the rotors, it became a pad & rotor issue. You've essentially gone back to square one. There is no pad transfer layer on the rotors, after they've been machined. So you need to rebed the brakes, this time only doing a series of near stops from 60mph (per: http://www.zeckhausen.com/bedding_in_brakes.htm). If the pads haven't been ruined from the abuse earlier, this should cure the noise. If it does not, then you should replace the pads.

Thanks for this info. I have been having a similar issue with the rear right on my 300C only when cold overnight. This has seemed to resolve this (where Chrysler service people say "this is normal, etc")

[DZeckhausen]

Originally Posted by wgondor

Thanks for this info. I have been having a similar issue with the rear right on my 300C only when cold overnight. This has seemed to resolve this (where Chrysler service people say "this is normal, etc")

Glad that fixed the problem. It's amazing how many people simply put up with brakes that sound like an old school bus. Even more amazing is how many people pay for new pads and rotors, when all they really needed was to give the brakes a good workout!

[Mr.SRT]

There is a TSB for this issue if your car doesn't have the slotted rotors that upgrades you to the slotted rotors.

Unfortunately brakes are a 12/12 item and alot of dealer are pretty strict about doing anything for free if its past the warrant able mileage or time.

[Cibalo]

I have the exact same problem on my SRT8, coming from the front right wheel. I went out today and did the series of hard stops from 60 to about 15 mph. After I started feeling the breaks fade I did it one more time and then bumped it up to 70 and cruised down the highway for about 3 miles did a quick turn around without stopping and cruised back into town.

On my way home I stopped to get some gas and head that same sound again from the same wheel. Do I need to go it again or at higher speeds?

I have an appointment with the service department at the dealership I bought the car from (not a Chrysler dealership) for Friday but if they aren't going to do anything I'd rather not waste my time. Only reason I was going was because I have a 30 day warranty.

[UK CHRYSLER 300C]

When we get motors in that have squealing brakes,we firstly chamfer the leading and trailing edge of the pad material(alot of manufacturers oe pads are chamfered)and this 99% of the time cures the squeal,unless is some other problem of course