New brakes - turn the rotors?

[Maestro]

Lol

 

[Maestro]

You just answered another question I had on my mind...

 

[Carlson-jet]

You really just ask that question

yes, I just ask it

Have you two worked for a brake manufacturing company?

If not relax. No need to try and prove a negative. The industry has screwed us all for years and always will until we figure out out how to stop without the current braking systems.

 

[lbhsbz]

They (rotors) typically don't "warp". They exceed run-out in the beginning with poor installation which is more than the caliper can absorb over time. ( special shims are made for this) If a rotor is not installed correctly and shows excessive run-out upon installation it will eventually catch up and pulse in the break pedal. Now there are instances where rust between the rotor expands or the torque to the hub is inadequate and causes excessive run-out. This is rare compared to improper machining and installation.

What you will never see are the specs for a given rotor or compounds that make up a particular pad given over the internet as they are proprietary. Good luck finding those specs.

Great post.

If anyone would like any specs on product produced by Centric, I can provide them. Be specific in your inquiries for accurate answers.

 

[lbhsbz]

Have you two worked for a brake manufacturing company?

If not relax. No need to try and prove a negative. The industry has screwed us all for years and always will until we figure out out how to stop without the current braking systems.

I've been with Centric Parts/Stoptech for 14 years. the industry has not screwed anyone. I'm curious as to where that comes from...

 

[lbhsbz]

I didn't come in here looking to argue...even though that's what usually ends up happening, my intention is to educate those with less knowledge than I have in my field such that others can end up with better results. Its really that simple. I'm good at certain things, I suck at other things. I accept advice on the things I suck at, I give advice on the things I'm good at. I'm good at brakes. My professional life has revolved around brakes for the last 14 years.

 

[rivermobster]

They (rotors) typically don't "warp". They exceed run-out in the beginning with poor installation which is more than the caliper can absorb over time. ( special shims are made for this) If a rotor is not installed correctly and shows excessive run-out upon installation it will eventually catch up and pulse in the break pedal. Now there are instances where rust between the rotor expands or the torque to the hub is inadequate and causes excessive run-out. This is rare compared to improper machining and installation.

What you will never see are the specs for a given rotor or compounds that make up a particular pad given over the internet as they are proprietary. Good luck finding those specs.

When you work at a dealership, specs for runout are readily available.

There are many different reasons a rotor can warp, or exceed the published specs for runout.

I can tell you from over 30 years of experience,. 002 or more, and you'll feel it in the pedal. . 003 or more is normally the alloted maximum runout per spec, and will have you feeling a lot more than a slight pulse!

Everything varies by vehicle. manufacturer though. BMW clearly states do not surface or replace rotors during a pad replacement, if they still measure good.

Each manufacturer is different.

 

[Carlson-jet]

I've been with Centric Parts/Stoptech for 14 years. the industry has not screwed anyone. I'm curious as to where that comes from...

Who manufactures/casts your rotors specifically and who finalizes the machining and on what machines and when was the last time they were new or rebuilt or how many hours are on them? What is the formula for all of your different brake pads? LOL

 

[lbhsbz]

Who manufactures/casts your rotors specifically and who finalizes the machining and on what machines and when was the last time they were new or rebuilt or how many hours are on them? What is the formula for all of your different brake pads? LOL

You said specs, now you're looking for contacts and internal information. Sorry, If you want specs I can help you...if you want to the secret formula to cokacola...call 'em up and ask em, my answer will likely be the same. We have too much invested to hand out that kind of information for free....or any price, really.

 

[lbhsbz]

BMW clearly states do not surface or replace rotors during a pad replacement, if they still measure good.

exactly right, because BMW OE brakes systems (Ate brake systems) utilize abrasive friction materials...the rotors are worn out when they're worn out. The abrasive pads keep the rotors clean and free from surface defects so there will never be a point at which an uneven surface condition exists. It's rare to get more than 2 sets of pads of a set of OE rotor though...and more often than not, one set of pad will wear out the rotors.

 

[Carlson-jet]

You said specs, now you're looking for contacts and internal information. Sorry, If you want specs I can help you...if you want to the secret formula to cokacola...call 'em up and ask em, my answer will likely be the same. We have too much invested to hand out that kind of information for free....or any price, really.

I added LOL. Lighten up. I know more than enough to know whats up in the brake manufacturing process. If you are saying the whole deal is legit, I give up. If brakes lasted forever there would be many jobs lost.

 

[TPC]

For those that do their own brakes or work in a shop, do you turn the rotors every time you change the pads? If not, when do you determine the right time to turn them is? How many times can a rotor be turned?

No.
Only if they are pulsing.

 

[rivermobster]

exactly right, because BMW OE brakes systems (Ate brake systems) utilize abrasive friction materials...the rotors are worn out when they're worn out. The abrasive pads keep the rotors clean and free from surface defects so there will never be a point at which an uneven surface condition exists. It's rare to get more than 2 sets of pads of a set of OE rotor though...and more often than not, one set of pad will wear out the rotors.

Yep. As a previous post stated, everything in the performance car world is about keeping unsprung weight down.

The days of having a rotor on a car you can machine three or four time are long gone. All the OEM's shave weight off in every area they can.

The last three or four manufacturers I worked for a all used Ate systems.

What OEM uses Centrex?

 

[lbhsbz]

I added LOL. Lighten up. I know more than enough to know whats up in the break manufacturing process. If you are saying the whole deal is legit, I give up. If brakes lasted forever there would be many jobs lost.

I don't know what you know, but I know enough that I can make the statement than at least 40%, probably more of the brake parts sold, and replaced, are completely unnecessary. I have calls for rebuilt calipers on 6 month old cars, master cylinders on cars less than a year old. We have 2017 info and parts developed and in stock...I'm amazed that they sell...and sell pretty damn well. It's indicative of the incompetence of a lot of today's "technicians". Blows my mind. If we don't sell it, someone else will so we might as well joint the party.

Edit, and its brake, not break

 

[rivermobster]

I don't know what you know, but I know enough that I can make the statement than at least 40%, probably more of the brake parts sold, and replaced, are completely unnecessary. I have calls for rebuilt calipers on 6 month old cars, master cylinders on cars less than a year old. We have 2017 info and parts developed and in stock...I'm amazed that they sell...and sell pretty damn well. It's indicative of the incompetence of a lot of today's "technicians". Blows my mind. If we don't sell it, someone else will so we might as well joint the party.

Edit, and its brake, not break

Sadly, this story is all too true! [emoji12]

 

[Carlson-jet]

I don't know what you know, but I know enough that I can make the statement than at least 40%, probably more of the brake parts sold, and replaced, are completely unnecessary. I have calls for rebuilt calipers on 6 month old cars, master cylinders on cars less than a year old. We have 2017 info and parts developed and in stock...I'm amazed that they sell...and sell pretty damn well. It's indicative of the incompetence of a lot of today's "technicians". Blows my mind. If we don't sell it, someone else will so we might as well joint the party.

Edit, and its brake, not break

I corrected my spelling at 12:48. 4 minutes before your correction thank you. LOL.. Take a BREAK, from brakes.

 

[lbhsbz]

The days of having a rotor on a car you can machine three or four time are long gone. All the OEM's shave weight off in every area they can.

The last three or four manufacturers I worked for a all used Ate systems.

What OEM uses Centrex?

Response to first line: no they're not.

Response to second line: you must have worked for VW, Audi, Mercedes, BMW, Volvo, Mazda or Ford

Response to 3rd line: It's Centric. We're primarily an aftermarket supplier. If you've ever seen a TRD big brake kit on a Toyota, we make those. Saleen and Roush brakes...that's our stuff. Dodge selected our rotors for the Viper ACR over brembo's offererings. There's plenty more OE stuff we do, but I'm not involved so I don't know the details. We are not mainstream like Akebono, PBR, Advics, TRW, or Bosch to any extent...we're mostly aftermarket.

 

[Carlson-jet]

Response to first line: no they're not.

Response to second line: you must have worked for VW, Audi, Mercedes, BMW, Volvo, Mazda or Ford

Response to 3rd line: It's Centric. We're primarily an aftermarket supplier. If you've ever seen a TRD big brake kit on a Toyota, we make those. Saleen and Roush brakes...that's our stuff. Dodge selected our rotors for the Viper ACR over brembo's offererings. There's plenty more OE stuff we do, but I'm not involved so I don't know the details. We are not mainstream like Akebono, PBR, Advics, TRW, or Bosch to any extent...we're mostly aftermarket.

I Hope you guys Continue to kick ass in the industry. We need every bit we can to stay state side. From the numbers, Aftermarket nets as well or better than OEM. Those numbers are convoluted though because a lot of OEM is actually aftermarket supplied. The proof is in the pads and rotors.

 

[lbhsbz]

I Hope you guys Continue to kick ass in the industry. We need every bit we can to stay state side. From the numbers, Aftermarket nets as well or better than OEM. Those numbers are convoluted though because a lot of OEM is actually aftermarket supplied. The proof is in the pads and rotors.

The only stuff that we produce stateside is our big brake kits on the Stoptech side. Our rotor rings are cast in Nor Cal and we perform all the machine work in our Compton facility.

As production parts go, there hasn't been an aftermarket brake rotors cast or finished in the US for probably 10 years. it's all China or Taiwan. We were all Taiwan for our premium line until our Taiwan plants all moved to china because they couldn't find labor in Taiwan. Not sure what's next...Veitnam, Africa? The quality hasn't gone down...if anything, it's improved because we babysit the factories and have very good relationships with the factory owners...one of them lives up the street from me.

 

[RitcheyRch]

I too like Akebono pads. I think shops not using a torque wrench on the wheels can also cause some issues with brake rotors.

For oe pads and rotors I suggest arkebono. I also like posi quiets pads. Cheap pads and rotors are just that cheap. They won't last and perform. Rotors do warp, distort, and become off center etc.

 

[240Hallett]

Why brand component were used on '03 GMC 1500 4w disc? I have over 172k and they still look good. If I ever have to replace I would want the same stuff. Is this dealer only parts?

 

[rivermobster]

Response to first line: no they're not.

Response to second line: you must have worked for VW, Audi, Mercedes, BMW, Volvo, Mazda or Ford

Response to 3rd line: It's Centric. We're primarily an aftermarket supplier. If you've ever seen a TRD big brake kit on a Toyota, we make those. Saleen and Roush brakes...that's our stuff. Dodge selected our rotors for the Viper ACR over brembo's offererings. There's plenty more OE stuff we do, but I'm not involved so I don't know the details. We are not mainstream like Akebono, PBR, Advics, TRW, or Bosch to any extent...we're mostly aftermarket.

Lincoln Mercury, Saab, Toyota, Lexus, BMW, Bentley and Rolls Royce.

 

[ToMorrow44]

Without reading all 8 pages, I'll just answer the OP question. I pretty much never turn rotors anymore, I replace them everytime. But I do it as a side business. New rotors and high quality ceramic pads and I have never had a customer come back and complain. Sometimes you can get away with pad slapping, but breaking performance can suffer and/or you can end up with a squeal. The ceramic pads, while they stop better, are quieter, and less dust, they're also harder on the rotor. Most OEM brakes are ceramic and will last 60, 70, 80k+ miles, so its worth it to spend a little more money and put new rotors on and do it right.

Long story short, if they're cheap just replace the rotors. At a MINIMUM, machine them. That way you wont have to go back and do it again.

 

[TPC]

Friend is a top mechanic at Galpin Maserati / Jaguar etc etc and says they usually don't "turn" the rotors on a routine brake pad change out.

 

[napanutt]

The ceramic pads, while they stop better, are quieter, and less dust, they're also harder on the rotor.

That's one of the reasons I go with ceramic. The wheels stay WAY cleaner.

 

[Uncle Dave]

Hawk pads are good aside from the HPS line. Worst street pads conceived by man.

If you are changing brake pad compounds, knock your rotors down quickly with 150 grit to rough them slightly. Spend about a minute per side. If you are using the same compound, throw them on and go. Only turn the rotors if they are grooved or you can feel imperfections with your fingernail.

I only use Brembo or Centric Premium or High Carbon blank rotors for replacements.

Never tried the HPS- but always appreciate hearing where not to go!

Ive been using their LTS light truck sport pads, and like them way better than the stock stuff and my Stillen Metal Matrix pads which I think were Akebonos.

THX!

UD

 

[Runs2rch]

Friend is a top mechanic at Galpin Maserati / Jaguar etc etc and says they usually don't "turn" the rotors on a routine brake pad change out.

Who? Is it Mick?

 

[Runs2rch]

That's one of the reasons I go with ceramic. The wheels stay WAY cleaner.

This is one benefit also new ceramic formulas are better all around. Wear, friction coefficient, and easy on rotors.

Not all pads are created equal!!!

FF or GG rated is what you want. It will be stamped right on the pad.

This two letter edge code mandated by the DOT, and painted on all street legal brake pads, will give you some indication of their ability to bite and resist fade, because of the wide range involved in each letter, it is only a rough indication.
Explanation of D.O.T. Edge Codes Located on all Brake Pads Official D.O.T. Edge Code Coefficient of Friction (C.F.)
@ 250 F and @ 600 F Comments
EE 0.25 to 0.35 both temps 0-25% fade at 600 F possible
EF 0.25 to 0.35 @ 250 F 0.35 to 0.45 @ 600 F 2% to 44% fade at 600 F possible
FF 0.35 to 0.45 both temps 0-22% fade at 600 F possible
GG 0.45 to 0.55 Very Rare
HH 0.55 to 0.65 Carbon/Carbon only. O.K. up to 3000 F where it glows

 

[LargeOrangeFont]

Never tried the HPS- but always appreciate hearing where not to go!

Ive been using their LTS light truck sport pads, and like them way better than the stock stuff and my Stillen Metal Matrix pads which I think were Akebonos.

THX!

UD

Yea I believe those are akebonos as well. I will have to try the Hawk LTS.

I run Centric Posi quiet on my 4Runner, they have been pretty good, very easy on the rotors, but a little less initial bite than I like.

I run Carbotech 1521 pads on mt CTS-v - Awesome performance street pad.

 

[TPC]

Who? Is it Mick?

Doug.

 

[ToMorrow44]

That's one of the reasons I go with ceramic. The wheels stay WAY cleaner.

Pretty much all newer cars within the last 10+ years come with ceramic pads...EXCEPT the german cars. All BMWs, Mercedes, Audis, VWs, etc come with old school semimetallic pads which turn the wheels black. For what reason? I don't know. And its hard to find ceramic pads for them in the aftermarket. Watch, next time you see a german car look at their front wheels...

 

[RitcheyRch]

I had Hawk LTS on my old 2002 Tundra trying to make it stop better since the factory system SUCKED on that truck. I didnt notice much of a difference over the factory pad other than noise.

I run Akebono Pro ACT (Ceramic) on our daily driven Civic's and have been happy with their braking performance and lack of noise and dust. My friends independent Honda/Acura shop only uses Akebono pads which is who did the work on our cars.

Yea I believe those are akebonos as well. I will have to try the Hawk LTS.

I run Centric Posi quiet on my 4Runner, they have been pretty good, very easy on the rotors, but a little less initial bite than I like.

I run Carbotech 1521 pads on mt CTS-v - Awesome performance street pad.

 

[pronstar]

Wife's Prius:
Turn rotors - $20/per
New rotors - $20/per

 

[rivermobster]

Wife's Prius:
Turn rotors - $20/per
New rotors - $20/per

Yeah, but you have connections us mere mortals don't.

O'Riley sells their "Brake Best" brand for 27.95, and the Bosch for 41.50. No doubt they are even more from the dealer.

I did my buddies Lexus is250 a few weeks ago. The factory pads lasted him 30k, and he had some aftermarket pads and rotors put on at that time (some super yazzo pads, that were supposed to keep his wheels clean).

I think it had 50k when I did them. The pads still looked new, but rotors were warped so bad, it shook the damm steering wheel out of his hands! lol

I told him to go the dealer and get all new pads and rotors. Drives perfect now. I'm not a huge fan of the aftermarket. It's not all that hard to wash your car.

 

[Waterjunky]

My 03 SVT Focus ate a set of rotors and pads every 70K miles. There was never enough metal left to even consider turning. I found this interesting considering this was a small light car that is massively over engineered for brakes (part of the SVT package).

On the other hand 08 Explorer Sport Trac finally needed front brakes at about 130k. Turning the rotors was about $20 each, new rotors were around $80 and up for anything decent. After cutting them, we checked them and I might even get another cut on them........ I was very shocked at all of this. then again as soon as you pick one up you realize that they are not light car rotor, there is a lot of metal in one of these.

 

[pronstar]

Yeah, but you have connections us mere mortals don't.

O'Riley sells their "Brake Best" brand for 27.95, and the Bosch for 41.50. No doubt they are even more from the dealer.

I did my buddies Lexus is250 a few weeks ago. The factory pads lasted him 30k, and he had some aftermarket pads and rotors put on at that time (some super yazzo pads, that were supposed to keep his wheels clean).

I think it had 50k when I did them. The pads still looked new, but rotors were warped so bad, it shook the damm steering wheel out of his hands! lol

I told him to go the dealer and get all new pads and rotors. Drives perfect now. I'm not a huge fan of the aftermarket. It's not all that hard to wash your car.

I bought everything thru Amazon :thumbup

Duro untreated rotors.
Paid about $80 for front and rear Akebono ceramic pads.

 

[rivermobster]

My 03 SVT Focus ate a set of rotors and pads every 70K miles. There was never enough metal left to even consider turning. I found this interesting considering this was a small light car that is massively over engineered for brakes (part of the SVT package).

On the other hand 08 Explorer Sport Trac finally needed front brakes at about 130k. Turning the rotors was about $20 each, new rotors were around $80 and up for anything decent. After cutting them, we checked them and I might even get another cut on them........ I was very shocked at all of this. then again as soon as you pick one up you realize that they are not light car rotor, there is a lot of metal in one of these.

No surprises here at all...

Performance cars always use the lightest components they can. For a whole lot of reasons. What you experienced is completely normal.

Trucks don't give a fuck about weight savings! lol They will still have big massive rotors, that will last, and be almost impervious to warpage. What you got there is normal as well.

Every manufacturer is different. Every vehicle is different. There is no "one size fits all" solution.

Think about this...

The OEM's have cubic dollars for R&D on the vehicles THEY build. The aftermarket cannot possibly afford do long term tests, on every vehicle out there. Their testing is done in house, not in real world situations.

Chose wisely. :cool

 

[rivermobster]

I bought everything thru Amazon :thumbup

Duro untreated rotors.
Paid about $80 for front and rear Akebono ceramic pads.

I bought a pair of rotors on Amazon ONCE. They ended up being boxed wrong. But the time I realized this, it was beyond the return period.

Lesson learned.

 

[lbhsbz]

Pretty much all newer cars within the last 10+ years come with ceramic pads...EXCEPT the german cars. All BMWs, Mercedes, Audis, VWs, etc come with old school semimetallic pads which turn the wheels black. For what reason? I don't know. And its hard to find ceramic pads for them in the aftermarket. Watch, next time you see a german car look at their front wheels...

It has nothing to do with semi metallic vs ceramic, it has to do with abrasive vs adherent friction materials. The euros generally use a softer iron in their rotor (referred to as Dampened iron or in the case of Centric, high carbon) closer to 18,000psi tensile strength along with an abrasive friction material on the pad such the friction is created by the breaking of bonds only. The dust you see is pad dust and rotor dust.

Most adherent systems will use 30,000psi grey iron for rotors and an pad material that utilizes a transfer layer on the rotor where friction is created by breaking and recreating those bonds...which is why you see less dust and rotor wear, and sometimes if all the stars are aligned just right (GM trucks), less pad wear.

 

[VoodooMedMan]

I bought a pair of rotors on Amazon ONCE. They ended up being boxed wrong. But the time I realized this, it was beyond the return period.

Lesson learned.

I'm not a huge fan of buying car parts online because of something doesn't fit or is DOA I need to be able to run to store and get a replacement. One of a few things I won't buy online.

That said I buy a ton on Amazon and their customer service is great. They would have taken a return IMO. Unless we just get special treatment since we buy so much.

 

[Chipster27]

All great info, thanks guys. I'll end up buying new rotors if we do these brakes again. As someone pointed out, and I confirmed on Rock Auto, you can get new rotors and pads for what I paid for my pads and rotors to be turned.

Do I dare ask about slotted/drilled rotors

I was looking a new pads/rotors for my F450, which tows a 18,000 pound 5th wheel. There is a "daily driver" set for $370 and a "tow package" set for $650. The tow package set appear to be drilled and slotted. Probably better pads too.

Are they worth the additional $300?

 

[Flying_Lavey]

I'm not a huge fan of buying car parts online because of something doesn't fit or is DOA I need to be able to run to store and get a replacement. One of a few things I won't buy online.

That said I buy a ton on Amazon and their customer service is great. They would have taken a return IMO. Unless we just get special treatment since we buy so much.

I was really leary of buy parts online also for that reason but, if you can plan the work far enough ahead of time and it not be something that needs to be done NOW, Rockauto can save you LOTS of money. For example, I can get new Moog upper control arms for my 1/2 ton silverado for $10 more than just the upper ball joint from Oreilly's.

 

[rivermobster]

All great info, thanks guys. I'll end up buying new rotors if we do these brakes again. As someone pointed out, and I confirmed on Rock Auto, you can get new rotors and pads for what I paid for my pads and rotors to be turned.

Do I dare ask about slotted/drilled rotors

I was looking a new pads/rotors for my F450, which tows a 18,000 pound 5th wheel. There is a "daily driver" set for $370 and a "tow package" set for $650. The tow package set appear to be drilled and slotted. Probably better pads too.

Are they worth the additional $300?

What's wrong with the rotors you have?

 

[lbhsbz]

Do not put a drilled rotor on a truck that sees high brake brake temps. 30 years ago when friction technology was crap it may have helped, but with modern friction materials, there isn't any benefit. Drilling through the casting creates stress risers and on applications that might overheat the rotors, a cross drilled rotor is much more likely to crack right through one of the holes than a plain or slotted rotor. It's mostly done for cosmetics these days. Remember, brakes convert kinetic energy into heat energy, that's it. The rotor is simply a heat sink and something for the pads to grab onto. Cross drilling can reduce your surface area by up to 15% when taking into account the chamfers on the holes, and certain rotors will lose up to 6% of their mass. This means that for a given braking event, the rotor will arrive at a higher temp faster, and cool faster than a rotor with more mass. Thermal shock is what cracks rotors. Stick with a premium quality plain rotor for HD applications.

 

[SBMech]

All great info, thanks guys. I'll end up buying new rotors if we do these brakes again. As someone pointed out, and I confirmed on Rock Auto, you can get new rotors and pads for what I paid for my pads and rotors to be turned.

Do I dare ask about slotted/drilled rotors

I was looking a new pads/rotors for my F450, which tows a 18,000 pound 5th wheel. There is a "daily driver" set for $370 and a "tow package" set for $650. The tow package set appear to be drilled and slotted. Probably better pads too.

Are they worth the additional $300?

Drilled rotors are not for anything but looks, unless you are running a race car with carbon. Vented seems to work best for heavy duty towing, drilling only lowers surface area and causes stress cracking or failure from rapid temp changes. Get the super duty stuff from Ford, you will be happy with it

 

[Chipster27]

What's wrong with the rotors you have?

Nothing, but when the truck is due I want to make sure I put on the best I can get. So these are not worth the money? Look at all their marketing claims, 180 degrees cooler, higher coefficient of friction than OE, Sever duty pads designed for hauling/towing.

Ironically Centric are listed under the "daily driver" category.

 

[lbhsbz]

Those are your typical commodity grade white box rotor with zinc plating and holes/slots, probably one of the least durable rotors out there. Marketing looks pretty good though

 

[rivermobster]

Nothing, but when the truck is due I want to make sure I put on the best I can get. So these are not worth the money? Look at all their marketing claims, 180 degrees cooler, higher coefficient of friction than OE, Sever duty pads designed for hauling/towing.

Ironically Centric are listed under the "daily driver" category.

View attachment 470096

As previously stated, truck rotors are Huge! You could machine those a couple times easy.

If it ain't broke, don't fix it. It would be unlikely they will ever warp.

P. S. Darryl was just here. You should ask him what he is up to...

😉

 

[Uncle Dave]

...when in actuality, this is what has happened: A judder condtion was present due to an uneven friction transfer situation, and someone took a perfectly good rotor, threw it on a lathe in an adapter fixture that didn't hold the rotor anywhere near straight, machine a bunch of runout into it while making 2 nice clean surfaces, patted himself on the back whilst reinstalling his newly fucked up parts, and sent the car down the road after steeling the customer's money. Why is the braking nice and smooth?...because both surfaces are parallel. Unless the runout is stupid excessive, the caliper will float back and forth and follow the brake rotor. Most vehicles use a floating caliper these days...fixed mount opposed piston calipers are less tolerant of runout, limited by speed fluid can flow through the crossover passage, before hydraulic feedback to the master cylinder, and a pedal pulsation occurs. I did it thousands of times when I was a dealer tech...I was wrong back then...I've since learned better. The car will come back with a judder, because the high spots on either side of the rotor over that period of time will pick up a different level of transfer lay from the pads than the rest of the rotor will, since those spots are contacting the pads more often and at slightly higher pressures than the rest of the rotor surface. If using an adherent pad, it can result in a buildup of friction material making a couple of thicker spots in the rotor. If using an abrasive pad, it can wear down those 2 spots...but this usually doesn't occur or last long enough to become noticeable because abrasive pads have a tendency to even things out, which is why with OE level components, Euro cars make lots of dust but almost never have brake pulsations or judders.

Nice write up.

The term Ive seen used for this condition is called "non uniform pad imprinting."

Often mistaken for a " warped rotor".


UD

 

[Chipster27]

P. S. Darryl was just here. You should ask him what he is up to...



I know he has a nice burn mark on his ring finger...:eek