warped rotors

[digitaldrifter91]

i have had my share of warped rotors. i found that it was a bad caliper that was barley noticable.

well 3 months so far and my rotors are fine. till today some unexpected 70-0mph stops very quickly. i did this about 4 times cause of some idiot on the freeway (without locking the brakes). now the last time i went from 70-0 the steering wheel went from left to right, i was like o no, and the car was shaking.

at low speeds now the car doesnt shake but past 55 it does.

i need a rotor that wont warp easily. these are napas rotor (lower end). so what can i do? hehe do you think its still under warrenty?

cross drilled rotors are out of the question for they are not too good, but cross drilled i am concidering. i dont want to spend alot of money to.

can i install new rotors with the older brakes?

thanks for the help guys. i know i am not a engine writer or anything but please bear with me =).

 

[Kernel Potter]

Here's a link the explains a lot of the factors involving brakes and a lot of myths about them.

http://www.stoptech.com/whitepapers/warped_rotors_myth.htm

Since brakes can get so hot and get hot fast, there's a lot of things that can be done to help ensure they work better, last longer with less problems and cost. One thing is to take it easy with new rotors and let them heat cycle many times before they get real hot. When you do start to cycle them hotter they should be incrementally brought up to higher temps and cooled until near maximum temperatures are ever reached.

Even after that process you should try to not let them get too hot too fast. They should be warmed up first before real hard use. It's esentially like the analogy of pouring hot water on an ice cube. Not a pretty thing for rotors

New brake pads need to be heated up also, to 'burn' out the bonding materials in the pad material. I had to do that again this year as my brakes were feeling weak. After a bedding cycle they felt very strong again.

Lastly, for street cars, cross drilled rotors(assuming they're manufactured and machined correctly) are generally considered benefical and acceptable since they don't see the type of temperatures that extreme racing will. The extreme temps will promote cracking.

 

[Steve S]

Excellent!!thanks for the link Kernel.

 

[TheLoneRanger]

That's very interesting, Kernal. The wife's vehicle had a bad case of the brake shudders. I assumed it was a warped rotor, but the runout checked OK on both sides. I was stumped. I had never heard of "cementite" or pad material transference, but that must have been the trouble.

I traded the car before finding out what was causing it.

 

[digitaldrifter91]

i got an update. well my rotors shook like crazy yesterday. well today they are fine. nothing is wrong and it seems the way as it was before. very smooth breaking, i dont know hwo this happend. im taking off the tire tonight and going to sand down the rotor a little and inspect.

 

[Kernel Potter]

Thanks for all the positive comments. Here's two more links I had found helpful. They give more detailed and specific information and how exactly to heat cycle rotors and bed brake pads.

I stumbled upon these links about 2 weeks before I installed some cross-drilled and slotted rotors(on an '87 Grand National) and I'm sure glad I did since a lot people do have problems with cracking etc. That was almost exactly two years ago and no problems as of yet.

http://www.baer.com/Support/TechTips.aspx?TechTipID=4

http://www.baer.com/Support/TechTips.aspx?TechTipID=5

 

[widman]

May have nothing to do with the problem at hand, but after changing out rotors, pads, pistons, etc. on my GLC, and using about every brake shop and dealer who might know something, I finally found that the inside of the brake hoses had become soft, so when they got hot they swelled, holding back the pressure.
New hoses solved the problem.

 

[digitaldrifter91]

interesting, that can lead to alot of money spent. how old was ur car widman?