wraped rotor? ACR

[SNKBYT]

I must have overheated my brakes at Pocono raceway this W/E. Had a HPDE there. Have a slight vibration on the left front when braking moderate to hard. Should I just replace the one rotor, and not the hat? Or would this be the time to upgrade to the ACR-X rotors? Will they work with my ACR calipers?

 

[bluesrt]

yes x rotors and pads will work with your acr ca;ipers

 

[SNKBYT]

Do I need the install the SS brake lines with the ACR-x pads and rotors? How common is it to warp a rotor on a ACR. I didn't think I was that ******* the brakes.

 

[bluesrt]

heat doesnt warp rotors, holding your foot on the brakes at a complete stop when really hot warps rotors, yes do the stainless lines, but you dont have to.

 

[bluesrt]

try not to hold your foot on the brakes when they are hot for now on, evan 5 seconds can do damage,come to stop,quickly shut of car and let off brakes at the trac

 

[Steve-Indy]

Can't disagree with above advice...but, I would certainly inspect everything first...check pads, check rotor surface (glazed??), check runout and thickness of rotors...then decide on best solution.

 

[bluesrt]

and allways tork wheels by hand with tork wrench,this can also warp a rotor

 

[cash84]

Another suggesting, did you switch pads on the same rotors? this can happen. I figured this out the hard way.

 

[SNKBYT]

I always torque the wheels with a wrench, and still have the orginal pads. Can I replace the one warped rotor and install new pads? If so, where is the best place to buy them? what pads would be best with the stock rotors?

 

[mjorgensen Woodhouse]

Try cleaning off ALL the brake pad material on the rotor surface with a rotary sanding tool and re do the bedding process. You could have excess or un even pad material on the rotor face from the heat and subsequent stop in the pits causing the juddering effect. I always cool the brakes on the "cool down" lap and still roll the car a couple times in the paddock to insure they don't over heat one area of the rotor. I'm ******* brakes and have never "warped" a rotor.

Just food for thought though.

 

[ACR steve]

^^ I agree with all above. I have been very very hard onthe brakes on track. It’s strange that you warped yours, they are excellentrotors. Check to make sure it’s not a tire or rim issue. Then check the padsthemselves look at the wear and color of them. Also check the rotor and see ifyou feel or see any irregularity on them .

No matter what the outcome is I recommend SS lines, better brake fluid and amore aggressive pad.

 

[Dom426h]

Just because the man says he warped his rotors dosnt mean so. Look at the facts and his symptoms.
Unless SNKBYT provides us with more info and says that after every session he pulled into the pits hot and yanked his E-Brake up then id say they are not warped

Will replacing your rotors and pads fix the problem? YES ....well atleast temporarily.
Could there be something else going on that is causing the rotors to feal warped even though they are not? YES

Mjorgensen is on the right track.

Brake pads work in an abrasive manor untill they get up to their adherent temperature. At the adherent temp a transfer layer forms and makes braking much more efficient. If cooled down properly the transfer layer stays in tact and is pretty durable but will wear off over time if the pads never get back up to the adherent temp. This is because the abrasive properties of the pad wear the transferlayer off at lower temps. If you never bed in your pads(most people dont) then your more likely to have no transfer layer or a weak patchy one that can create vibrations or fealing like your rotor is warped. There are a number of factors that can cause your transfer layer to become uneven/patchy and give you the "warped rotor" feeling.

To fix this, Properly bed in you pads. You can do this anytime. New or old.
You basically just need to find a long straight road. I like the freeway during off hours(like 3am...) Then do two bed in "sets". A bed in set is multiple consecutive hard braking applications to get the pad up to its adherent temp to spread a transfer layer, then continue driving for like 15min to let the system completely cool WITHOUT touching the brake. If you touch the brake or come to a stop then you can disrupt the transfer layer from properly curing.

If you would like to learn more about this then i suggest reading the following article on the stoptech website:
http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths

Also i think that Every article in the Stoptech's TECH section should be required reading for anyone that is serious at the track. Educate yourselves. Understand your equipment. Dont rely on other ametures and old-timers with outdated myths to fill you mind with misinformation.

http://www.stoptech.com/technical-support/technical-white-papers

ENJOY

 

[PJ9454]

DOM426, thats great info. I road course race and always follow the procedure for break in. BUT I never knew why there was a specific procedure. That "transfer layer" really explains it well and its actually helpful to know why, so you do it right. Great post for sure.

 

[SNKBYT]

What pads do you like to run with the stock ACR rotors? Where can I get them?

 

[345s-bspinnin]

Talk to Mark Jorgensen. He can help you choose from a wide range of pads; from pure track to some street. Aside from the obvious, there are many factors to consider, including noise, dust, and general wear.

I have stoptech ACR rotors. I do 2-3 track events a year and the rest is street driving. Mark was able to provide just the right pad that's better than OEM at the track, but still civil for street duty.

 

[Chuck 98 RT/10]

Another vote for MJorg's advice.