Proved to myself that rotors do not warp!!

So I had the typical brake shake in the steering wheel that many of us have experienced at highway speeds. below 40 or 45 it was almost not noticable.

 

A little background about my setup:

2007 STi calipers, DBA4000 slotted rotors, hps pads, ss braided lines.

Everything was installed about 15,000 miles ago.

 

So I decided to jack the car up, pull the front wheels and check the runout (at the edge) of both front rotors.

Front left was 9/100 of a mm (or 0.0035", or 3.5/1000") so just barely out of the 3/1000" spec.

Front right was 28/100 of a mm (or 0.0110", or 11/1000") so way out of spec!!

 

I first removed the front right rotor and cleaned it as well as I could from brake deposits. I noticed that the face of the hub where the rotor mounts was rusty, so I cleaned that as well as the surface of the rotor where it sits on the hub. I put everything back together and checked the runout again..

 

To my surprise it was 2/1000"!! within spec..

I did the same to the left side and got it to be within spec as well.

 

Saved myself a hassle and mistake from running to the machine shop or buying new rotors. Just an fyi that you may want to try this if you suspect that you have "warped" rotors

You got lucky .

 

Most rotors don't warp much anymore, it is the thickness variation around the rotor caused by pad transfer and surface corrosion that is the culprit.

 

However, the mating surface is super important. I usually spreak some brake anti-sieze on the mating surface between the rotor and hub to stop corrosion. Cleaning the mating surface between the wheel and brake disk is equally important.

 

Good job though, did you drive it and confirm the shimmy was gone?

Everybody knows that brake rotors CANNOT warp. The inclusion of runout "specs" in all manufacturers service manuals is also proof of a massive conspiracy being perpetrated by brake rotor suppliers in conjunction with the auto companies.

You got lucky .

 

Most rotors don't warp much anymore, it is the thickness variation around the rotor caused by pad transfer and surface corrosion that is the culprit.

 

However, the mating surface is super important. I usually spreak some brake anti-sieze on the mating surface between the rotor and hub to stop corrosion. Cleaning the mating surface between the wheel and brake disk is equally important.

 

Good job though, did you drive it and confirm the shimmy was gone?

 

The rotors actually came off pretty easily. I removed the caliper and a few taps on the back of the rotor with a rubber mallet freed them from the hub.

 

I suspect that the mating surface was the main issue causing my problem. I also rebed the pads as suggested in stoptech's writeup.

 

All seems to be good so far

There is also risk in taking your rotors to a machine shop to be turned down. If the mating surface on the lathe is not within spec, that will transfer to the rotor, possibly making it worse than what it was.

There is also risk in taking your rotors to a machine shop to be turned down. If the mating surface on the lathe is not within spec, that will transfer to the rotor, possibly making it worse than what it was.

 

Yup, exactly the reason I'll only resurface rotors with an "on the car" brake lathe. Your also at the mercy of the lathe operator setting up the cones correctly when you take them off and have them done.

Everybody knows rotors are made of adamantium, there for they cannot warp.

Everybody knows rotors are made of adamantium, there for they cannot warp.

 

No, wrong....everybody knows it's just brake dust that build's up and needs to be cleaned off. Re-bed the brakes. You guy's and you high tech metals.....dreamers. You just want to spend money....

and the most effective cleaning method is?

^ new rotors

^ new rotors

 

 

HAhahaha......useless

I had the "brake shake" with my oem pads. then i got HPS w/o touching the rotors and the shake eventually went away.

and the most effective cleaning method is?

 

http://legacygt.com/forums/showthread.php/video-article-swap-between-street-and-race-pads-139306.html?t=139306

 

Also, the following is a good one, too:

 

http://legacygt.com/forums/showthread.php/video-bed-brake-pads-and-rotors-126622.html?t=126622

 

 

I got some mystery brake squeek and noises two winters ago. I did just about everything to try to find (and cure) the problem.

 

One day, it just suddenly went away.

 

For the longest time thereafter, I couldn't figure it out, then I realized that I'd driven *much* harder the day that the noise went away - I'd effectively re-bedded my brakes. While I knew that brakes had to be bedded the first time around, for some reason, it never occurred to me that it's a process that will need to be repeated.

Everybody knows that brake rotors CANNOT warp. The inclusion of runout "specs" in all manufacturers service manuals is also proof of a massive conspiracy being perpetrated by brake rotor suppliers in conjunction with the auto companies.

 

No they don't:lol: