Very bad brake shudder when they heat up

[hognutz]

2007 300c 5.7L with 13k on the clock

took a trip up a peak the other day and on the way down the brakes got warm and just had terrible shudder.

when the brakes are cold they do react a bit weird at high speed ~80mph or so. they turned to complete junk coming down the peak we drove up.

I tried re-bedding them but they are still crap.

now my question is the car only has 13k on it. Is the problem the stock pads, rotors, or both.

I was going to buy some new pads and turn the rotors but then I got thinking if the stock rotors were crap too I might as well do both.

also suggestions of pad brands would be appreciated. should I go with centric, stoptech, hawk, ebc some aftermarket brand or just stick to autozone, nappa, parts store brand.

If I need rotors I was leaning towards the centric.

[GMACJR65]

I would not turn the rotors at all, that just makes them thinner and they will warp easier, I would get new rotors. Hawks are great but costly. I have used wagner thermoquiets on my wifes envoy and will be trying these on my 300c when needed.....Good luck!

[rakimb17]

13k? That sounds like a warranty issue to me. Is the whole car shaking or is it just pedal vibration?

[stevesrt8]

please read this tech paper:

StopTech : Balanced Brake Upgrades

It is against the odds that you have 'warped' rotors. What most people really have is pad deposits welded onto the rotor face.

If they won't come off with bedding then you need to turn the rotors. Removing a few thousandths of an inch will not predispose you to 'warp' again.

Then bed them properly and learn not to sit with your foot on the pedal at lights after a hard stop.

That's it.

[hognutz]

Originally Posted by rakimb17

13k? That sounds like a warranty issue to me. Is the whole car shaking or is it just pedal vibration?

when they get hot it gets terrible. well my issue I don't want to be in the waranty marygo round. if this is a poor material choice from the factory I would rather just replace it with different material. just trying to figure out if this is a comon problem or I have a special case. waranty work with me is love hate. If I have a known TSB and they just do the work I don't mind it. If I go in with a problem like this they usually piss me off. if you keep it under 80 and do one stop at a time the brakes don't feel that bad.

geting them fixed for free and being back in another 10k is more of a pain to me than just fixing it right at is only a 30minute job.

If I had not driven up the steep windy road I would not relize how bad it gets. on flat ground cold most people might live with this. I won't because I like things to work correctly.

[hognutz]

Originally Posted by stevesrt8

please read this tech paper:

StopTech : Balanced Brake Upgrades

It is against the odds that you have 'warped' rotors. What most people really have is pad deposits welded onto the rotor face.

If they won't come off with bedding then you need to turn the rotors. Removing a few thousandths of an inch will not predispose you to 'warp' again.

Then bed them properly and learn not to sit with your foot on the pedal at lights after a hard stop.

That's it.

I have read all these white papers before and it is good info but doesn't phyically fix my issue or even make me understand why this would happen that quick.. Bedding did not work so I obviouly have to choose a solution. either turn and new pads or new rotors and new pads. turning is less money but i just want bakes that last.


so do you think the factory never bedded them popperly?

or the stock pad material is more prone to deposites?

driving style is a non issue I have never had this problem before with any other car.

[stevesrt8]

Yes, it is a pad issue. You might want to also inspect the tie rod ends.

The factory does not bed the brakes. That takes several consecutive stops... but wait, you already knew that.

This issue occurs most often in cars where people sit at a light with the brakes clamped down hard and the deposits weld themselves on.

Maybe yours are unique.

[mtroute]

Originally Posted by hognutz

I have read all these white papers before and it is good info but doesn't phyically fix my issue or even make me understand why this would happen that quick.. Bedding did not work so I obviouly have to choose a solution. either turn and new pads or new rotors and new pads. turning is less money but i just want bakes that last.


so do you think the factory never bedded them popperly?

or the stock pad material is more prone to deposites?

driving style is a non issue I have never had this problem before with any other car.

I have the same problem on my '06, it is not a warped rotor otherwise it would shudder all the time. Whats happening is that brake material that deposited on the rotor seems to create less friction as it warms. Since the deposits are not uniform areas with less deposits have more grab creating a grab-slip-grab-slip issue. Bedding the brakes now might still work if you do it a few times. One solution that I have seen mentioned is to use racing pads with aggressive formula to basically strip the old material off like sandpaper and then switch back to a road pad. The was a link a while back, I'll see if I can find it.

edit: ok I found the link.

http://www.zeckhausen.com/avoiding_brake_judder.htm

[hognutz]

yeah I read that article but the idea of installing pads to surface the rotor seem like extra work and money. Just for the record I have never though my rotors were warped. other people have just infered it because I mentioned turning them. I would only turn them to remove the deposits.

I will turn the rotors and give the centric ceramics a try(unless someone else has a better suggestion). this is just a street car I have an 07 z06 for track use or hard driving. I was just paranoid to reuse the rotors because the brakes got some bad so fast and some people have said that once you get the deposits and you can't see them that just turning the rotors might not always cure the problem

figured I would just purchase from Zeckhausen Racing since he post here and give info.

[hognutz]

well I was bored today and decided to just do this on the cheap first time around and see how it works out. had the rotors turned and got some new car quest ceramic pads $60 total. shudder or judder is gone but now the car pulls to the right when you brake hard.

any ideas on what to try first. there are obviously multiple causes for this but what is the most likely cause in my case? the car did not do this before I did the work. I was going to inspect the left brake line first make sure it looks fine. Just not sure what would be the best course of action to figure out what the real cause is. is this most likely a presure issue or mechanical issue?