'04 4.4i Front Rotors Warping

[ncsucarjock]

Folks,

Noticed that my front brakes were very lightly warped about a month after I got it (almost a year ago). Not bad, just a slight pedal pulsation on light pedal effort from high speed. Anything more than light pressure, and it disappeared, or at low speeds (less than 40mph) it was not present.

A couple months ago, I replaced the OEM pads and rotors, and replaced with Zimmerman Rotors, and EBC Red Stuff pads. Some two months later I have the exact same symptoms. Wheels are always torqued with a torque wrench, so I'm not warping them through poor wheel installation technique.

I'm concerned that my driving habits are just hard enough that these front brakes are just on the verge of being able to withstand the abuse. Not that they're horrible, and in fact, I have never had an issue with not having enough braking power...I'm just worried that when they come to rest, there isn't enough brake rotor to be a big enough heat sink, and that i'm warping them after a hard couple stops and then parking it. That I live .25 miles off the local interstate doesn't help, because I brake hard oftentimes from 70-80mph, and then come to a complete stop 1/2 mile later.

Anyone else experienced this? I'm debating upgrading to the 4.8is front brakes...though it's a lot of dough... thoughts?

[FSETH]

Did you bed the brakes properly?

Instructions for bedding in your brakes

Read this regarding warped rotors and brake "judder".

StopTech : Balanced Brake Upgrades

[JCL]

Good links above, have a look at them.

I would add that your brakes do generally have sufficient thermal capacity. Getting them hot and then parking isn't a problem; getting them hot and then sitting with your foot on the brake is how you get a pulsing.

[rocky1536]

Maybe its a control arm issue?

[m5james]

Originally Posted by JCL

Getting them hot and then parking isn't a problem; getting them hot and then sitting with your foot on the brake is how you get a pulsing.

They taught us in driving school that we should either put the vehicle in park and/or use the parking brake in situations like this. I highly doubt that most daily drivers will get their brakes that hot on the street to justify these techniques.

I agree w/ FSETH that it probably needs to be bedded better. Also, for some reason people over look this, but a nice fresh brake FLUSH, not just bleed at every brake job should be a requirement in my book.

[ncsucarjock]

Brakes were bedded in according to the EBC red-stuff instructions. Similar to the link, but not quite the same (and different from any other pad I've installed...and after probably 200 brake jobs, I'm fairly skilled and knowledgeable about installing brakes and bedding pads).

Fluid was flushed when I did this job, as I did all 4 wheels, and it's just a good maintenance practice.

I had hoped that new rotors and pads would cure the situation, however it hasn't. It took about two months for the vibration to start. The EBC red stuff pads have a break-in period of 1000 miles, which I passed in the first 2 weeks. I'm wondering if there isn't some uneven pad deposits, but it'll be hard to tell. I may try pulling the rotors and having them turned ever so slightly, and then re-bed the pads. But I'm afraid more than anything that this darned exit ramp is my problem. Pads are warm, and I come off, brake hard from 70+ (sometimes well above that). Go less than 1/2 mile, and shut things down, resulting in a very hot pad sitting in one spot on the rotor. The obvious answer would be to not do this...but...it's oh-so-tempting...it's a beautiful exit ramp...

[primetime]

I seriously doubt it has anything to do with the exit ramp and then shutting the car down soon after. I would keep investigating...

[ncsucarjock]

How much heat is generated in heavy braking in stop and go? And then jump on the highway for about 2 miles, hard accelleration and braking, speeds in excess of *25, hard braking (just before abs kicks in) clip the apex of the ramp, turn right, and then stop 100 yards later? Just saying...

This isn't the first car that's done this since moving here...and it's the only commonality between them.....

[motordavid]

Why not roll home, that last few miles of the interstate and the get off, a lil' less aggressively?

[primetime]

Let me elaborate my story a little bit...I do the same thing, my exit ramp is even less then 100 yards from my house and I come off the freeway everyday doing 70 mph. I brake how I want to, sometimes hard or soft, whatever the situation warrants, and i've never had this problem, and mines an 01 sport with 20's on it.. I'm confident that this wouldn't cause any problems with rotors warping. There would be a ton of people complaining about this problem and this is the first time i've ever seen anyone mention it relating the 2 things..

Also if you drive and stop aggresively (which it sounds like you do, no problem there but just saying) I would suggest upgrading to the Brembo big brake kit all the way around (yes $$ i know) or like you said going up to a 4.6 or 4.8 brake upgrade..