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Warped rotor... twice in a year with VWR Racing brake set...

J

jrkob

Ready to race!
GIACUser said:
No way you are warping those rotors driving around on the street.
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GIACUser, just as a matter of disclosure, yes I exclusively drive my car to and from work and I am really careful about doing anything crazy as I "need" my car to work. But once in a while, say once every 3 weeks, I will have a high speed run over a distance of, on this straight line I think it is 2 km, at 200km/h, then I will brake heavier than usual. May be quite hard, I am not sure I am not an expert. But say heavier than usual.

Would your analysis change given this occasional high-speed run ?

Also, just to confirm that I may proceed with this bedding-in even if none of my rotors or pads are new ? My problem occured after driving 10,000km with the new rotors and new pads. So they are not "new" per se.
 
eldiablo1

eldiablo1

Ready to race!
jrkob said:
Awsome, thank you ! With my brakes, should I follow the Bedding-in Street Performance Pads or the Bedding-in Club Race or Full Race Pads procedure ?

Cheers
Click to expand...

if you have an appropriate roadway to follow high speed race pad procedure, go for it.

otherwise, you will probably see improvement following the street procedure.

Please make sure you're surroundings are safe to be going from high speed to panic stopping conditions (over and over) as indicated in the procedures.

And also make sure to NOT come to a complete stop "during" either procedure. It's important to let the brakes cool after putting them through this process. Also important to NOT engage your parking brake after completing the procedure.

After the brakes are allowed cool for a while, you will probably see a dramatic improvement in their performance (high / hard pedal).

Good luck! Keep us posted.
 
eldiablo1

eldiablo1

Ready to race!
jrkob said:
Also, just to confirm that I may proceed with this bedding-in even if none of my rotors or pads are new ? My problem occured after driving 10,000km with the new rotors and new pads. So they are not "new" per se.
Click to expand...

Absolutely. Older pads can benefit from a bedding procedure if you have deposits on the rotors (which it sounds like you do).
 
J

jrkob

Ready to race!
J

jrkob

Ready to race!
eldiablo said:
Absolutely. Older pads can benefit from a bedding procedure if you have deposits on the rotors (which it sounds like you do).
Click to expand...

Thanks for the help. Will report.
 
K

kri$han

Passed Driver's Ed
eldiablo said:
What seemed to be warped rotors was just uneven build-up of material on the surface of the rotor.
Click to expand...

Please don't confuse my post for "knowitallism", but this is the case in almost ALL passenger vehicles with "brake shudder"... it is almost always un-even pad wear.

To truly warp a rotor, you'd have to be using it lie a Le Mans, or F1 race-car, where the rotor gets so hot, it glows red!

In university, I had a chance to meet and discuss braking technology and failure analysis with the president of Stop Tech, at one of the Formula SAE finals in Michigan; he mentioned this to me, that it is almost ALWAYS un-even pad wear, caused by:
- improper or inadequate brake pad bed-in procedure
- low quality, or misused (i.e. track-use of street) brake pads
- low quality, or misused rotors (using rotors that aren't high enough performance for your application), or
- installing rotors backwards (so that the internal vanes aren't venting gases properly

I'm thinking the last one could be the OP's problem (no offense, but it is an easy mistake to make)

:thumbsup:
 
bebersol

bebersol

Ready to race!
warped or not

The only way to know if the rotor is warped is to check the run out. This can be done on the car or on a lathe. Eyeballing won’t tell you. If the rotors were warped and you had them turned, they will re-warp, period. Rotors can warp by driving hard and hitting puddles where water gets on the rotors. The wrong torque of the lug nuts could be a factor on one piece rotors but yours look like 2 piece aluminum hat rotors, it’s probably not the lug nuts torque causing the problem.
If your brake pads are sticky try this. Clean and regrease the caliper slides. Press the brake pedal first before trying to move, the pressure will crush the oxidized iron into a powder. If you’re using racing pads they are much dirtier and much more prone to moisture stick, and don’t get water on the rotors until thay are cooled or you’re asking for warped rotors.
 
zrickety

zrickety

The Fixer
It's not that hard to warp a rotor. Over tightened lugs as mentioned earlier will do it. Many garages don't use a torque wrench and instead use an impact gun/wrench. Sometimes so tight the lugs can't be removed by hand tools.
 
G

GIACUser

Master Wallet Mechanic
jrkob said:
GIACUser, just as a matter of disclosure, yes I exclusively drive my car to and from work and I am really careful about doing anything crazy as I "need" my car to work. But once in a while, say once every 3 weeks, I will have a high speed run over a distance of, on this straight line I think it is 2 km, at 200km/h, then I will brake heavier than usual. May be quite hard, I am not sure I am not an expert. But say heavier than usual.

Would your analysis change given this occasional high-speed run ?

Also, just to confirm that I may proceed with this bedding-in even if none of my rotors or pads are new ? My problem occured after driving 10,000km with the new rotors and new pads. So they are not "new" per se.
Click to expand...

No, my analysis is really just me sharing my experience with you and what I have had to do with some of my cars. Those rotors won't warp with street use, the way you are driving they probably have a hard time staying hot. To heat warp them you would have to actually be doing competitive racing, a bunch of it, this would be hours of very hard full force braking. These are designed for that kind of abuse. Doing 8-10 pull downs from 120mph is no big thing for those brakes. I have no idea what pads you are using but changing them could get rid of the problem you are having.

If you really feel they are warped, pull them and take them down to brake shop and have them check the run out for you. The cost to check them is probably zero if it is a shop you use or just a few bucks. Of course before you do that, look for brake pad build up and if you have it, just remove it with some emory cloth and a block OR do the bedding in process to remove it. Bedding in process basically scrapes it off.

Good luck.
 
J

jrkob

Ready to race!
eldiablo said:
And also make sure to NOT come to a complete stop "during" either procedure. It's important to let the brakes cool after putting them through this process. Also important to NOT engage your parking brake after completing the procedure.
Click to expand...

Guys, just a quick update.

I have followed the procedure in the "Race or Full Race section" of the weblink provided by eldiable.

Howver... after the run, which I think took me like 20 minutes or so, I immediately stopped the car and engaged the parking brake. I wanted to check my brakes... I immediately remembered the "no parking brake" thing and because I wasn't sure, I did the whole run again. Then drove again normally on the highway for half an hour without braking much, and then stopped the car.

Is this ok ?

In any case, I have 2 observations to make:
1- my rotors look much "shinier" than before, really look good now. The dark spots have disappeared.
2- no more "vibrations". I think.

Is there anything else I should be doing ?
 
J

jrkob

Ready to race!
GIACUser said:
These are designed for that kind of abuse.
Click to expand...

Thank you. This is also what I thought...
In the past after coming back from work I touched with my fingers the rotors with my finger and they didn't seem hot at all. As in I could leave my finger there and not be burnt at all.

After doing the "bed-in" run yesterday though, I couldn't touch the rotors at all, way too hot. In fact, I tested my rotors with a corner of my credit card and it melted immediately.
 
eldiablo1

eldiablo1

Ready to race!
Sounds good! Glad to hear the vibration is gone. It sounds like the bedding procedure helped to remove the old brake pad deposits.

How are the brakes performing now? Better?
 
whatisthatsound

whatisthatsound

Passed Driver's Ed
I think you'd benefit from reading this.

http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths

I have never found an mechanical engineer who has said it would be possible to warp a rotor. You can cause uneven wear, but actually warping a rotor is next to impossible. A lot of the issue you described are either from uneven wear or rust forming on the rotor after rain, which is what you feel when breaking free after it sits for a few days. I don't know much, I have the internet for that!
 
J

jrkob

Ready to race!
whatisthatsound said:
I think you'd benefit from reading this.

http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths

I have never found an mechanical engineer who has said it would be possible to warp a rotor. You can cause uneven wear, but actually warping a rotor is next to impossible. A lot of the issue you described are either from uneven wear or rust forming on the rotor after rain, which is what you feel when breaking free after it sits for a few days. I don't know much, I have the internet for that!
Click to expand...

Wow, this is an extremely interesting article, thanks a lot for posting it.
In fact, it looks like what my problem was was excessive "easy braking" as per the article, considering my driving style.
Appreciated !
 
J

jrkob

Ready to race!
eldiablo said:
How are the brakes performing now? Better?
Click to expand...

It's hard to say because I very rarely really slam on the brakes. I only noticed this problem because of the vibrations, not poor braking. As I generally brake gently, I am not seeing any difference in efficiency, only the vibrations are gone.
 
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