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Drilled and Slotted Front Rotors

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  #21  
Old 10-09-2013, 01:26 PM
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Originally Posted by Jodele
Exactly wrong to what all the brake manufactures say to do...on both sides of the Atlantic. AP Racing (of England) and StopTech (of California) publish "bedding in" procedures for breaking in the brakes. They also say to repeat the bedding in process of the brakes start to vibrate. I suggest you do a little reading before writing garbage.

I agree without the gabage comment its just inexperience.
We've changed thousands of pads and shoes and the best bedding procedure is to repeatedly go hard on the brakes from 60 to 20 at about 0.5 g until the brakes feel a little soft - fading- and drive several miles without using the brakes at highway speeds. Far as I know thats the recommendation from Ferodo, Performance Friction, Hawk, Raybestos and 'Wooly'. In our case most of the new pads were subjected to severe service shortly after being bedded in. without problems.
In the OP's case I think he's using brake pads too soft for his driving and I recommend going to Hawk HPS. Tho we have yet to experience pads that get brake pad residue coating eriodically th rotors so it appears warped Iwon'tsay it doesn't happen if your pad ceramic composition is soft. Every time we turn rotors we look for pad residue by swabbing eith acid but as of yet haven't found it. Then we rarely come across OEM pads either. Did hear that a number of inferior pads will leave definite coatings when the car is stoppped with hot pads.
PS have you tried TireRack or Brembo.com? for really good rotors ?
 

Last edited by mahout; 10-09-2013 at 01:30 PM.
  #22  
Old 10-09-2013, 01:43 PM
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Originally Posted by mahout
We've changed thousands of pads and shoes and the best bedding procedure is to repeatedly go hard on the brakes from 60 to 20 at about 0.5 g until the brakes feel a little soft - fading- and drive several miles without using the brakes at highway speeds.
This is what I do and what I was trained to do and what I continue to do.

I believe companies that recommend taking it easy on brakes for x miles are simply catering to the lowest common denominator. The vast majority of people don't care enough to follow some procedure, and shops just want to get the cars in and out these days, they "don't have time" to bed pads for you.

It is very easy to tell if you have pad deposits on the rotors or if you have run-out, that should be a non-question to any tech after about 2 minutes with a gauge.
 
  #23  
Old 10-09-2013, 04:48 PM
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Originally Posted by Wanderer.
This is what I do and what I was trained to do and what I continue to do.

I believe companies that recommend taking it easy on brakes for x miles are simply catering to the lowest common denominator. The vast majority of people don't care enough to follow some procedure, and shops just want to get the cars in and out these days, they "don't have time" to bed pads for you.

It is very easy to tell if you have pad deposits on the rotors or if you have run-out, that should be a non-question to any tech after about 2 minutes with a gauge.

There are lots of formulations for brake pads, most using Barium Sulfate with binding materials and thermal /reinforcing strands. Some of those binders are fully cured when produced and aren't very good at high temperati=ures so overheating woulfd be wasteful.
Most, if not all, good pads that have high friction coefficientsare not fully cured. Thats why the bedding process takes the surface to high temperatures and matches the pad to the rotor. So its not always best to bed rotors to the high temperatures that induce fade. Those that do are ridding the surface of gases that would be detrimental. As the bed wears down those gaseous components are burned off before reaching the surface just as the bedding process intends - for good pads. For those of us, like you, who use only good high performance pad materials the repeated high temp 'burst' is the best but those who buy lower quality pads should not overextend the pad when bedded in, or matched to the rotor. Unfortunately, its no longer a good selection based on cost, as good ceramic bimders do cost more, but the market pricing that yields high profits that has countered the price is quality process.
Buyers should use pads with proven performance. The best way we know is see what showroom stock racers are using and follow suit.

When we measure rotors for true the defection of the disc measured with laser does not differentiate warp from deposits. Only by trimming the deflection back to true surface and testing the shavings is good. Magnetics won't do but chemicals will. So far we haven't really found deposits, only metal, but I believe deposits do happen.
PS those who recommend that the brakes not be used hard for the first 500 miles after replacement never drove in todays traffic. It'll never happen.
cheers.
 
  #24  
Old 10-09-2013, 06:50 PM
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What if we just slap on a set of OE pads?
 
  #25  
Old 10-10-2013, 09:12 AM
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Originally Posted by Steve244
What if we just slap on a set of OE pads?

Expect results for 'normal' driving if you drive 'normally' but if you brake later, harder, and/or more often OEM falls a tad short for front brakes. They're OK on the rear as only 30-35% of braking is done by rear brakes.
My guess is if braking is hard enough to warp the rotors or melt pads leaving residue on the rotors then first you need better brake pads. Replacing rotors with better metallurgial composition applies after upgrading pads and still getting warped rotors. And that gets into race track driving. Shouldn't need that on the street.
 
  #26  
Old 10-11-2013, 09:04 PM
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Originally Posted by Jodele
No...rear brake adjustment is not a factor. Mine were adjusted all of the time. The dealer even replaced my front rotors twice under warranty! If you brake hard all of the time, you get thickness variation (incorrectly call warping). The front brakes are just too small... Once I installed the ITR front brakes, all vibrations went away.
Originally Posted by Jodele
OK...so you're driving Miss Daisy. A BBK is not in your future.
Originally Posted by Jodele
A drag strip is only hard on your tires and transmission... Go drive on a road circuit or a mountain road and see how long your brakes hold out.
Originally Posted by Jodele
Exactly wrong to what all the brake manufactures say to do...on both sides of the Atlantic. AP Racing (of England) and StopTech (of California) publish "bedding in" procedures for breaking in the brakes. They also say to repeat the bedding in process of the brakes start to vibrate. I suggest you do a little reading before writing garbage.

Lol at this guy. Sounds like he can read brochures......

Op I live in AZ if u need help pm me. I'm a gm master tech, ase master tech with the L1 and I road race my fit with NASA AZ. So I know a little about brakes. Like I said its driving style that makes brakes vibrate. If u need help finding upgrades I can tell u what to do and what not to do.

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  #27  
Old 10-13-2013, 10:19 PM
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Originally Posted by Previc93
Lol at this guy. Sounds like he can read brochures......

Op I live in AZ if u need help pm me. I'm a gm master tech, ase master tech with the L1 and I road race my fit with NASA AZ. So I know a little about brakes. Like I said its driving style that makes brakes vibrate. If u need help finding upgrades I can tell u what to do and what not to do.

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Those instructions are valid for good brakes based on tests by the manufacturers. So tell us what brakes you use in your NASA events. Most of us here in NASA SE use Hawk. GM had serious problems with rotors warping when they tried toget away with cheap metallurgical rotors and the probnlem was only solved by better rotors. Disca on the front are usually vented, meaning they have two p'plates' separated by a gap; Its esy to get rotors overheated on the inside where ventilation is not as good and where the metallurgy isn't good the plates do warp. Thats why you get runout different on the inner and outer plates. Often its seen by finding the vent slot between plates varying in width. When brakes pulsewhen they are applied its a good sign the rotors have warped nbut it also can be from pad residue on the rotor.. Nowdays few rotors are of poor metallurgy but even then excessive heat will warp the rotor; most of the time now its in track duty. And better disc pads have an advantage of not transferring heat between the pad surface or rotor in the pad so the pads don't overheat as easily and avoid fade. And better brake pads will have more costly binders that withstand high heats as much as 1800F where those cheap pads rarely withstand more than 850F Thats when too much heat absorbed by the pad melts and offgasses the binder so the pad is lubricated by the gases and brakes don't work. There's little that will create panic more than no brakes approaching turn 1 at 155 mph.
Brake pads are one area where cost is pretty indicative of value but like I said see what showroom stock racers are using and do likewise.
 
  #28  
Old 10-16-2013, 05:00 AM
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Most of the drilled rotors you see are the same blanks you would buy from pepboys just drilled and slotted. Thats why most will crack. The slotted will hold up fine. Also if you go with Brembos or the costly companys they designed the rotor to be drilled they will also hold up fine.
 
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