By on November 8, 2019

Best Replacement Brake Rotors

TTAC Commentator tonycd writes:

Hi, Sajeev! I’m a long-ago occasional TTAC contributor, occasional B&B pontificator, and longtime admirer of your column, with a question of my own.

My brother just picked up a very used ’09 Mazda6 Grand Touring V6. Lotsa horses, in need of brake service to rein them in. He’s hearing and feeling a pulsing through his brake pedal, sort of a low rhythmic moaning tone. It could be wear indicators, but more likely it’s a warped front rotor. Either way, he’s pretty confident he’s going to have to replace all the friction materials, including the rotors.

Which leads to my question: What’s a not-crappy brand of brake parts? He doesn’t want to expend all the labor on replacement, only to have them immediately warp again the first time he heats them up (which he will – especially with 274 ponies, he’s an, er, enthusiastic driver). Everybody knows Brembo, but who else sells quality?

Sajeev answers:

Doing the brakes on a used vehicle of unknown history is always a smart idea. Which is a rather huge understatement!

Several vendors make consistently good brake parts, but I doubt their superiority on a street-driven vehicle. I’ve used the cheapest rotors possible (that still met OEM design standards) with decent quality semi-metallic, ceramic or carbon-metallic pads and never had a problem.

For me, it’s more about the pad than the rotor. Even on track-focused cars, there’s a lot to like about cheaper rotors when it’s your wallet on the line.

So I doubt your brother’s recent purchase of a “very used” 10-year-old Mazda needs nothing more than new rotors made to OEM standards, ceramic or carbon metallic pads, and the proper break-in procedure applied.

Unless he does track day events every month and drives on the street like a maniac (and I mean go-to-jail maniac), he won’t have an issue. I saw no concerns about rotor thickness/warping for GEN II Mazda 6s on google: anything I found could easily be a poor choice in brake pad.  This is “just” a 3,600 lb car: while Brembo has a well-deserved reputation for excellence, nobody’s perfect. Stoptech makes people happy (I’ve used Centric, the parent company’s cheap stuff, with success) and the Internet’s also kind to Powerstop.

But can you trust anyone’s opinion on aftermarket upgrades? Hell to the no: everyone’s gonna feel an improvement going from used pads/rotors to brand new ones. Even if they honestly realize there’s no improvement on public roads, will anyone swallow their pride and say “I made a mistake buying this stuff when the factory-designed bits were just as good?” 

Positive internet feedback is probably the most misleading thing in our industry.

My advice: get Raybestos brake rotors and ceramic brake pads of your choice.  I’d personally go for cheaper, off brand rotors, but I’d hate to be wrong with someone else’s whip.

Send your queries to [email protected]com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice. 

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65 Comments on “Piston Slap: Deep-Sixing Unknown Friction Materials?...”


  • avatar
    Vulpine

    To counter that last sentence in the response, my own experience with ‘cheaper, off-brand rotors’ has been that they were made to OEM MINIMUM standards…or rather, to only a millimeter or less of ‘time to replace’ size–having the one set I bought that way start warping within maybe 45-60 days before becoming noticeable in both pedal and ride. Now, I will grant this was some years ago in a car I no longer own but because of that I never go ‘cheap and off brand’ any more.

    • 0 avatar
      James Charles

      Vulpine I think you will OEM parts are generally at the minimum standard, or close to it.

      Don’t don’t confuse limits for repair, ie, repairable/usable with manufacturing limits. They are different.

      I would hardly think many reputable companies would distribute auto parts that don’t meet OEM limits.

      As the author wrote, unless you are driving criminal crazy brakes are quite duarable. Its heat that kills brakes, or most an engineered component.

  • avatar
    TheFirehawkGuy

    The most important part of the brake job is simply doing it correctly. Too many people just slap the new parts on and call it a day. Get that wire brush out. Clean the rim and hub surfaces. Brake cleaner on ALL THE THINGS! Check for play in the bearings, make sure all the points of motion are properly lubed. Replace the sliding pins if necessary. Not 100% sure of the condition of the hydraulics? Get a pressure reading at each caliper to make sure you have even and full pressure at each wheel. Make sure there isn’t excessive lateral runout on the new rotor. If there’s more than .005″ get a shim. Lastly DON’T OVER TORQUE THE LUGNUTS! There’s super tight tolerances engineered into modern wheels. Thousandths of an inch to account for different expansion rates of dissimilar metals and the torque spec matters to those tolerances. Overtighten the lug nuts and you will end up with a pringle shaped rotor faster than you can say “once you pop the fun don’t stop” Once you’ve done all that, just follow the manufacturers break in procedure for the new parts.

    • 0 avatar
      gtem

      This right here. Clean the hubs of any rust (OEMTools sells a great Hub resurfacing drill attachment for $13 on amazon), then spritz with some fluid film to keep rust at bay, clean/grind the caliper pad interfaces of rust, apply brake grease where needed. Relube caliper slide pins, use appropriate pad shims/hardware. A proper brake job is a lot more than just slapping new rotors and pads on as quickly as possible.

    • 0 avatar
      ToolGuy

      Yes, torque the lugnuts. (Install/tighten by hand [socket in fist], ensuring no lateral play from wheel to hub. Lower vehicle to ground. Torque in ‘star’ pattern across the wheel. Then quickly recheck in clockwise pattern to be sure nothing is missed.) [This is not a dealer – we have standards – lol.] Remove all tension on your torque wrench before storing it.

      [If anyone tells you to lube the rotor/pad braking surfaces, they are lying – you will crash. Have known of people playing this ‘joke’ on newbies.]

      One excellent brake cleaner is Tetrachloroethylene. (It is dry cleaning fluid – you can use it to remove spots on clothing.) [Do NOT use it to clean parts for welding – you can create Phosgene (think WWI poison gas) – at the hospital they will make you comfortable while they watch you die.]

      “Warping” is not warping.

      Little-known fact – most brake rotors are cast iron.

  • avatar

    No expert, but it would seem prudent to buy the best one can afford and accept that – if a lower priced item was purchased – one may have issues sooner than if a more expensive option was used. FireHawk makes a good point. It’s more than just slapping things back together.

  • avatar
    tylanner

    I’ve switched to aftermarket Brembo on my daily because it only cost about 2X an OEM brake job(VW) and I’ve had about enough Autozone/Amazon special weekend afternoons.

  • avatar
    ajla

    The only repair issue I’ve had on my Stinger dealt with the OEM brake pads. Apparently Kia was so worried about noise and brake dust that they equipped North American cars with pieces of Havarti inside the fancy-looking Brembo calipers. Within a year, they were toast and the dealer replaced the pads & rotors under warranty. It’s fine now but unless they updated the design I expect the issue will come back.

    Next time the fix won’t be free so I’ll be either using G70 pads or something aftermarket (the rear size is weird so not many options right now).

  • avatar
    Jon

    I read an article in my favorite automotive publication a year or so ago. It was written by someone representing EBC brakes. The writer stated that if there is a mild pulsation in the brakes, the driver should perform these steps before purchasing new rotors.

    1. Bring the vehicle to 60+ mph.
    2. Perform hard braking, without locking up the tires, down to 10mph.
    3. When the vehicle reaches 10mph, VERY GENTLY apply the brakes until the vehicle stops.
    4. Once stopped, do not wait. Immediately repeat steps 1-3 four to fives times.
    This process will heat up the brakes significantly.

    The purpose behind these steps is that sometimes the binder (glue) holding the pad material together will build up over time on the rotors. If the brakes are heated up but not applied gently when coming to a stop, the binder will build itself into mounds on the rotors; thus causing pulsating.

    The reason for the steps above is to redistribute the binder uniformly (as much as possible) to the rotor. This is accomplished by heating the rotor and slooooowly removing pressure from the pads.

    • 0 avatar
      Flipper35

      I have never seen a bedding procedure that has step 3 and when you are done, make sure you cruise long enough to cool everything down before you park. That said all the factories specify different procedures.

      From Tire Rack with some of the pads they sell.

      AKEBONO

      400 to 500 miles of moderate driving is recommended. Consumer should avoid heavy braking during this period.
      ATE

      400 to 500 miles of moderate driving is recommended. Consumer should avoid heavy braking during this period.
      BREMBO GRAN TURISMO

      In a safe area, apply brakes moderately from 60mph to 30mph and then drive approximately 1/2 mile to allow the brakes to cool. Repeat this procedure approximately 30 times.
      HAWK

      After installing new pads make 6 to 10 stops from approximately 35 mph with moderate pressure. Make an additional two to three hard stops from approximately 40 to 45 mph. Do not allow the vehicle to come to a complete stop.When completed with this process, park the vehicle and allow the brakes to cool completely before driving on them again. Do not engage the parking brake until after this cooling process is compete.

      Note: Hawk racing pads (Blue, Black, HT-10, HT-12) may require a different bed-in procedure. Contact your sales specialists at the Tire Rack for racing application information.

      • 0 avatar
        Jon

        “I have never seen a bedding procedure that has step 3”

        This really is not a bedding procedure for new brakes. It a procedure for used rotors.

        Step 3 is the key to the entire process. A lot of people perform this procedure and ignore step 3 by suddenly stopping. When the brakes are hot, sudden stopping is exactly what builds up the binder on the rotor. This step can even be applied to everyday driving.

    • 0 avatar
      rpn453

      I would avoid coming to a complete stop during any bedding or conditioning procedure until the brakes have cooled right off.

      Since I started bedding brake pads after installation, I’ve never had any pulsation except on the one set that I didn’t have time to bed!

    • 0 avatar
      macmcmacmac

      I just replaced the rear brakes on my friend’s 2010 Sonata and noticed the old rotors had quite a buldup of black, glassy coating that I could chip off easily with a cold chisel. I tried to eke out one more winter with the now clean but somewhat mottled rotors but they always made an annoying swishing sound. New rotors and pads solved the issue, but it was hell trying to figure out why I could not get the new rotor on the right side. The parking brake was ever so slightly seized on, preventing it’s easy installation. I’m sure the neighbours didn’t approve of the language.

      One caveat, avoid Canadian Tire OE Plus pads. These are the only pads I ever used that I had to grind into the proper shape before the back plate would actually fit in the caliper.

      I have also found that you can get a lot of noise from the rust ring that forms just outside the swept area of the pads. These will drag along the outer edge of the pad and create noises like the front wheel bearings are about to fall out of the car. They are easily dealt with by a ball pein hammer or angle grinder. I wonder how many people got talked into an expensive repair because of this.

  • avatar
    Daniel J

    I had a 2010 Mazda 6, non-v6 version and I warped the factory rotors at 35K miles. Had the dealer turn them, warped them again about 55K miles, which at that point all the pads needed replacement as well and I replaced rotors since they couldn’t be turned again.

    • 0 avatar
      Flipper35

      Always check for run out, Sometimes it is an uneven layer of material from the pads that makes the brakes shudder.

      • 0 avatar
        JMII

        Warping rotors is pretty rare, as mentioned above its normally just a build up of pad materials. New pads along with the bedding procedure would step #1 in my book. If the vibration remains then get new rotors.

        I would add that checking the hubs for play is also recommended before blaming the brakes.

        The only rotors I have ever truly warped where OEMs units. Both on my Dodge truck (towing) and my Corvette (tracking). Even the Corvette made it thru 3 track days before the rotors were a wobbly mess. I tracked my 350Z on cheap Centric rotors and never warped them.

        Its hard to justify spending big money on rotors, after all they are just a ring of metal. Other then corrosion coatings on the hats and maybe different vane designs for cooling they are pretty much all the same. Thus any name brand will be fine. PowerStop makes kits for most cars and sells on RockAuto at really good prices. That is the route I went on my wife’s Infiniti when her brakes wore out.

  • avatar
    indi500fan

    I’ve had good luck with Akebono pads.
    In general, parts produced by Japanese suppliers in USA plants are high quality.

    • 0 avatar
      slavuta

      I used Akebono ceramics a lot. They are quiet, and soft on rotor. But are dusty and don’t give enough grip to my taste (on large vehicle). So, for small car may be ok

  • avatar
    slavuta

    This is from current owner of 2010, 2011 mazdas and also 2017 (no brake jobs yet), and previously – 1998…

    Sajeev said, “For me, it’s more about the pad than the rotor.” – hahahaha (Scotty Kilmer)

    What I found out is that when it comes to Mazda, rotor is more important that pad. Both, ’10 and ’11 cars had one issue – early rotor death. Because those rotors developed rust behind spindle and that rust encroached on pad-touching surface and ruined the pads along the way. So, I realized that Mazda OEM rotors are not good.

    What I did, on ’10 AutoZone Duralast Gold rotors and same brand ceramic pads. On ’11 – Car Quest (Advanced autoparts) Wearever rotors and OEM pads. Both setups work well and last good, only ’11 setup has noticeably better grip (I bet ceramic pads is the difference). So there we go. With coupons, these can come very cheap and OEM pads I get on eBay.

  • avatar
    StudeDude

    Over the past 35+ years of doing brake work, I have found many decent brake part suppliers. They include more recently Centric, Raybestos, Duralast, Wearever and Wagner. I agree with FirehawkGuy regarding many of his comments. I would also replace the brake hardware if you want to do a complete job. The kits from Rock Auto are relatively inexpensive and contribute to the way the pieces fit together and may even affect the durability of the brake job. If the car has high mileage or is of a certain age (15-20+ years), I would also give a serious look at the brake hoses and master cylinder.

  • avatar
    MoparRocker74

    I recently replaced my stock R/T pads/rotors with the Power Stop Z26 Street Warrior kit. That one includes the slotted/crossdrilled rotors. MUCH better response, although I haven’t had a chance to give it a hot supper north of 100 mph….yet. Virtually no brake dust at all—the stock parts were notorious for dirtying my wheels with that crap. They include everything you need, I did the installation myself with a buddy as my extra set of hands/beer disposal unit in about 2 hours.

    Shop that kit on Summit Racing. It got to me in a couple days, and for my car that front/rear set is usually $446. I caught a sale and there was a promo code so I got it for $385 shipped. Can’t beat that!

    Oh and my car is a ‘09 manual R/T with 45K miles. Stock parts still probably had 50% more life.

    • 0 avatar
      ToolGuy

      “Virtually no brake dust at all—the stock parts were notorious for dirtying my wheels…”

      Another case of OEM’s not delivering as well as aftermarket.

      Proposed workaround: All performance-oriented vehicles/packages should offer wheels which are the color of brake dust.

      • 0 avatar
        MoparRocker74

        The OEM parts are always going to be built to a price point at which you’re getting something that keeps the MSRP in check, performs acceptably for most customers and of course there’s a list of (mostly idiotic) regulations to meet. In the case of the stock R/T brakes they’re adequate until you hit that 100mph mark then the weaknesses come out—they’re not up to task, IMHO. So while that’s a bit frustrating, Mopar has plenty of upgrades in house and no self respecting gearhead is content with bone stock pieces or being afraid to crack open the toolbox. There’s definitely a sense of satisfaction that comes with owning an upgraded car, and even moreso from doing even simple jobs yourself.

      • 0 avatar
        JimZ

        brake friction materials are a balance between:

        – long pad life
        – low noise
        – low dust
        – good “bite”
        – good braking when cold
        – low rotor wear

        you cannot get a pad which gives you all of them. the “aftermarket” may sell you a pad which is better at one or two aspects, but it’ll be at the expense of others.

        • 0 avatar
          ToolGuy

          JimZ,

          Excellent point. But we can also add “cost” to that list, as MoparRocker74 points out. (And given the new and improved list, I’m not sure the OEM makes the same tradeoff that I would choose for myself.)

          • 0 avatar
            JimZ

            OEMs want to avoid noisy brakes because customers complain about them and take the car into the dealer. they want long pad life because customers don’t accept a 30,000 mile interval for brake jobs anymore. they want a pad which works over a broad range of temperatures, because unlike a race car “the brakes need to be hot to work effectively” doesn’t fly in the real world. and yes, cost has to be reasonable.

            Thus, you get pads which generate dust.

      • 0 avatar
        JMII

        I put the similar “daily driver” Z23 PowerStop kit on the my wife’s Infiniti Q60 and reduction in brake dust was downright remarkable. At first I though the “dust free” was just marketing BS but honestly its true. The initial bite of the pad is slightly lower then OEM (Akebonos) but you get used to it very quickly.

        For my C7 Z51 I went with graphite colored wheels because I liked the look (not a fan of black or chrome) plus it does help hide the dust. In fact I jokingly refer to the color as Brake Dust Grey Gloss Coat.

  • avatar
    Terry

    35 years as a Mazda Master Tech and Dealer Shop Foreman. 1) Machining brake rotors is a thing of the past, when domestic vehicle rotors had much more material and you could machine them .060” from new. These days, machining rotors is an invitation to a repeat warped rotor party. Not enough material to begin with, and rotors cut thinner can’t absorb and dissipate the heat and warp even earlier. It also helps to use a die-grinder with 2” brown Scotchbrite Rolock abrasive discs on the wheel hub side of the rotor and Mac Tools hollow discs around the wheel studs. With Mazda you can order the oem pads that came on the car, or use the less expensive Mazda Value Pads. Both work well and you know they’ll fit well. And both will come with new anti-chatter pads. The Value pads will have them attached to the back of the brake pads. Change/ flush the brake fluid at a minimum of 2 year intervals. Your ABS pump/hydraulic control unit($2800) and your wallet will thank you. You’ll also have a better brake pedal feel.

    • 0 avatar
      Jon

      Terry,

      Why change the brake fluid? Is it due to heat, moisture, something else? Does this recommendation vary by region/climate?

      • 0 avatar
        Terry

        DOT3 and DOT4 brake fluid absorbs moisture which can lead to valve sticking and seal deterioration. The black you see in old fluid is from moisture and in some cases microscopic particles of internal seals. Siphon out a brake(or clutch) And look at the sludge build-up in the bottom of the reservoir.

        • 0 avatar
          Jon

          Terry,

          If the brake system is sealed, where does the moisture come from: atmosphere, breakdown of chemical composition of the brake fluid, etc.? (I understand that no systems are perfectly sealed etc.)

          The reason i ask is that I live in Phoenix. Our streets and atmosphere are devoid of moisture 340 days a year. I’m skeptical that there is enough moisture present in the atmosphere to find its way into the brake system.

          • 0 avatar
            MBella

            It’s not sealed. Otherwise the brakes wouldn’t work.

          • 0 avatar
            bullnuke

            Brake fluid is hygroscopic (tends to easily absorb moisture from the atmosphere). The reservoir on the master cylinder is vented to atmosphere. When the brakes are applied, the level in this reservoir drops a bit as the fluid fills the wheel cylinders which sucks a bit of the atmospheric air into the master cylinder and reservoir brake fluid. Over time the moisture entrained in this atmospheric air migrates through the brake fluid and throughout the entire system.

          • 0 avatar
            JMII

            A brake fluid tester is only $10 on Amazon, money well spent to me. I live in FL which has crazy humidity and I track my car so keeping tabs on brake fluid is high priority.

    • 0 avatar
      johnny ro

      Brake fluid testers which dip into the master cylinder are nice but the fluid is not on an out and back circuit so does not indicate water in the slave cylinders. Also a rubber hose is not exactly impermeable, nor are the seal interfaces. HOH gets in. Flush is good, and a DIY quality one-man push bleeder setup is under $20 on amazon.

    • 0 avatar
      ToolGuy

      This string right here is the kind of thing that keeps me coming back to TTAC.

  • avatar
    Scoutdude

    I made the mistake of going with cheap rotors on our Mountaineer and within a year or so (~5,000mi on that vehicle) they were warped. I did go with the PowerStop rotor and pad package on my F250 and so far so good about a year and ~4,000mi later.

  • avatar
    JimZ

    rotors don’t really “warp.” As previously mentioned a pulsating pedal can come from heat checking, material transfer from the pads causing thickness variation, or uneven cooling causing thickness variation.

    • 0 avatar
      Vulpine

      Thickness variations is still warping–taking the surface away from flat to curved. A steel straightedge can reveal the warping very easily if it reaches a point of being manually detectable.

      • 0 avatar
        MBella

        Yeah, this has been one of the stupid things on the internet. It’s like saying that’s not a dog, it’s a Canis familiaris. Just because one is the technical term doesn’t make the common term wrong.

        Modern rotors, especially for Asian and domestic vehicles are very rarely stress relieved. With modern ceramic and semi metallic pads, the stress is released while driving. After new rotors on these vehicles, I typically recommend driving it for at least 5000 miles even if you start getting a pulsation at around 1000. By that time, they should have been heat cycled many times, and any stress should be released. If you machine the face at that point, it will usually be pretty stable, and last for the life of the pad.

        On European cars, the rotors and pads are made from softer materials, and under normal use they usually don’t have the same issue. They do wear out dramatically faster.

      • 0 avatar
        White Shadow

        It’s not warping. The thickness variation is from pad material being unevenly distributed on the rotor. Warping is not the same thing.

    • 0 avatar
      Scoutdude

      While thickness variation is more common actual warping, where they take on a potato chip shape does occur too. I’ve seen it many times where the first cut takes material off the outside ~180 degrees from where it is taking it off the inside.

    • 0 avatar
      slavuta

      Brake can pulsate from people not cleaning spindle well before replacing the rotor. Or even, if you don’t apply even torque to all lugs – eventually it will lead to problems with pads, etc

  • avatar
    Land Ark

    I had a pulsing on my Legacy that shook the steering wheel. It was bad but consistent. When slowing from >40mph it would shake and then once down to around 25 it would stop.

    I figured it was the result of sitting, that rust had built up and it would probably eventually wear off. I decided not to wit and ordered OEM rotors and pads. Everything looked fine until I took the rotors off (original OEM) they had been completely chewed up and there were extremely deep gouges all around the inside top of the front rotors. I still have no idea how they got there. After replacing everything it’s smooth as silk, but I am worried something is misaligned and it will happen again. So far so good though.

  • avatar
    pwrwrench

    I’m with Terry and Studedude. Most “smaller” vehicle rotors cannot be successfully reconditioned. They will warp, soon.
    Some of the “heavy duty” 3/4 ton or higher GVWR stuff can be machined and reused.
    And do not ignore the “rubber” parts. After 8-10 years the hoses will often get internally restricted. Then they become check valves and the caliper will not release properly leading to overheated brakes and warpage. Then there’s the master cylinder and calipers. Eventually caliper pistons will stick and need replacement. This is usually worse in areas with cold winter’s.
    I learned the hard way, more than 30 years ago, to use only known or OEM brake parts. ATE, Gurgling, Brembo, and Pagid are OEM on many Euro cars and often available at other sources than the dealer for less. Motorcraft and others are available for USA cars. Similar with Asian cars, Akebono, Nissin, and others can be found.
    Most of the “discount” stuff is barely better than metal to metal.

  • avatar
    Terry

    On a brake lathe I chucked up a few rotors and using a dial indicator I would see a .015” or more variation and marked the high spot on the rotor. Then I would move my dial indicator to the other side of the rotor and see the same variation in the same location but with a low area. So YES brake rotors can and do warp, along with the afore-mentioned heat checking and pad material transfer from sitting. I’ve also had instances of collision damage where the wheel bearing flange (wheel stud mounting flange) was bent causing l as feral movement of the brake rotor. Defective wheel bearings can also cause this issue.

  • avatar
    Terry

    Lateral came through as feral, damn spell check. One area of Missouri State Vehicle Safety Inspecton is cracked brake hoses. Even just the outer covering would result in an inspection failure. In the Mazda’(and similar Ford Escape) the front brake hoses would crack and leak resulting in a low pedal and stained underwear. My own ‘05 Tribute had this happen. Restricted brake hoses were mostly a Mazda3/Protege’/MX-3/323 issue, always found in high-mileage vehicles with zero brake fluid changes.

  • avatar
    Terry

    Jon, look at your brake fluid. If it’s considerably darker than fresh fluid you have deterioration of the fluid taking place. By its nature brake fluid is hygroscopic, that is it drays moisture out of the atmosphere. And there is a deterioration of seals in master cylinders, calipers, and wheel cylinders. I’ve seen wheel cylinders that would draw air into the system when the pistons retracted with minimal leakage under pressure. One of the main points of brake maintenance/repair – like any maintenance repair-is that you’re not just replacing parts. You’re servicing a SYSTEM. No different than replacing a water pump for example and not checking the thermostat, radiator, hoses, and belts. To service front brakes without even checking the rears, parking brake system, fluid or master cylinder is false economy in terms of time, effort, and money, let alone your personal safety.

    • 0 avatar
      StudeDude

      Terry—totally agree regarding the brake fluid flush/change. I always bleed out as much of the old fluid whenever doing a pad or pad/rotor change. It’s cheap insurance for keeping the hydraulic system fresh.

  • avatar
    JimC2

    Just a couple things to add:

    Regarding brake wear indicators, not all brake pads have these reeds built in (most don’t). Sometimes brand new pads squeak starting the day you put them on the car- either from dirt (see TheFirehawkGuy’s post about cleanliness and being thorough) or a cheap pad (some just squeak more than others).

    Regarding brake fluid changes, the system is not completely sealed- the reservoir is vented, and over time the fluid in there gradually absorbs moisture from the ambient air. The guy who lives in Phoenix has an advantage here. There are probably plenty of 20-30 year old cars running around there on their original brake fluid and they’re not crashing daily… that speaks for itself. But no matter where you live, it’s never a bad thing to replace old brake fluid in your car.

  • avatar
    Crosley

    If the brake pedal is pulsing while stopping, it means the rear rotors are warped. Not the front.

    If the steering wheel is shaking while stopping, it’s the front rotors.

    • 0 avatar
      White Shadow

      Incorrect. If you feel any pulsation in your brake pedal, it can be any or all of the rotors that have excessive thickness variation. What you are feeling in the pedal is the caliper piston(s) moving in and out slightly as the rotor turns.

  • avatar
    Add Lightness

    Coming down a mountain pass converting 5,000 vertical feet of potential energy to kinetic energy and then to thermal energy will usually separate good discs from crappy ones.

  • avatar
    nrd515

    I started warping rotors on my ’85 Caravan and had warped rotors on every single one of my cars, trucks, and SUVs from that point on. Some would just warp a little, some really badly. My 2010 Challenger warped rotors soon after I got it and they kept warping. Several friends of mine with LX and LC cars had the same issues. After 2 sets of factory replacements that warped within six months, I went to look for something better. I ended up buying slotted and dimpled rotors from “Brake Performance” and just picking them up you could tell they were different. They were a lot heavier than the OE junk. Once they were on, my warped rotors were just a bad memory. Same went for my friends, if we went to decent aftermarket rotors, no more warping, The factory ones always warped. The last 3 years I had my ’10 Challenger, I never had even a slight shudder, and had the best brakes I’ve ever had until my new car with huge Brembos front and rear. And those have shown no signs of warping.

  • avatar
    pwrwrench

    Warped rotors happen, along with rust and pad material on the friction surface.
    Back in the day when diagnosing brake pulsation, on cars with out ABS, it was found that often the rotor had very little or “0” runout when checked with a dial indicator. That was when things were at ambient temp. Drive the car, get the brakes hot, put it up on the hoist and quickly remove a wheel. Checking the rotor when it was hot, lots of runout. So new rotors were needed to fix the pulsation.
    Sometimes the steering wheel would shake, sometimes not. This probably had to do with if only one rotor was warped or if both were warped, whether they were “in sync”. Which would change as the car was driven as the wheels rotate slightly differently when driving around corners or on uneven roads.
    The scary part is not only drivers/owners that don’t maintain their brakes or repair them poorly, it’s also those that get paid to do it and should know something about the job.
    Back in the 1980s I went to a training class for brake work. The instructor told us some of his experiences being a rep for a brake parts company. He would go to shops where they were having problems servicing brakes.
    In one incident he watched a “mechanic” replace the front rotors, pads and wheel bearings on a Corvette. The brake fluid was replaced with new. So far all seemed good. Then came the test drive.
    Riding with the “mechanic” they went onto a road with no traffic. The “mechanic” accelerated to about 50 mph, held his foot on the throttle, and pressed his left foot on the brake pedal. Then he began sawing the steering back and forth zig zagging down the road. When asked what he was doing the “mechanic” replied that he was, “giving the rotors a non-directional finish.”
    Now the rep new why that shop was having problems with rapid wear and fade with new brakes.

    • 0 avatar
      JimC2

      “Then he began sawing the steering back and forth zig zagging down the road. When asked what he was doing the “mechanic” replied that he was, “giving the rotors a non-directional finish.””

      HAHAHAHAHAHAHA!! Oh boy… that’s the kind of thing they tell the new guy in the shop, which is usually the guy who gets to test drive the customer’s Chevette, not the guy who test drives the Corvette.

      We could have a whole article dedicated to rookie mistakes made by shops, anything from overtorqued lug nuts with the air gun maxed out to the sky’s the limit… probably get hundreds of comments on that one too, it might be cathartic but it could be dangerous too.

      • 0 avatar
        pwrwrench

        According to the class instructor, that guy was not a “rookie”, but had been a “mechanic” for decades.
        In over 30 years fixing vehicles I have seen many “improved” repair techniques learned through word-of-mouth, gossip.
        People sometimes leave parts off when reassembling something. When asked why they are doing that they say, “that stuff isn’t needed” or “it works better without that”. Like cooling system shrouds.
        Long ago I saw a guy, at a Chevron station I worked at briefly, light COLD vulcanizing cement on fire while “repairing” a punctured tire. When I asked him why he was doing that when the cement can label read, “Caution Flammable, keep away from fire or flame!” He replied, “That’s a HOT patch!”.
        I also recall a study that was done in the 1950s, by IIRC, UCLA. They investigated vehicle crashes. The consensus, up to that time, was if there was a crash it was always the fault of the driver. Again IIRC they found a substantial % of the crashes were caused by mechanical problems. Non-functioning brakes, tires that deflated or came off wheels, steering parts that broke. Much of this was due to poor repairs or maintenance. Some to poor design or engineering.
        Think about all that, next time you are out on the road.

  • avatar
    tonycd

    Thank you, Sajeev. My brother is most appreciative of the advice. And he gives a shout-out to Terry for the brake fluid flush advice as well.

  • avatar
    pwrwrench

    It’s important to consider how brakes function. They slow/stop a vehicle by changing the energy of the vehicle moving into heat. The mass of the brake(s) needs to be sufficient to absorb and store that heat, in the most energy intensive brake use, and not get so hot that something in the system fails. After brake use the heat can be transferred to the air. If rotors get to hot they will warp, crack, or even fall apart. Brake fluid can boil and friction materials will have much less friction when overheated (brake fade).
    Manufacturers are obviously trying to minimize the cost of production. A pound of cast iron not put into making the rotors, on one vehicle, will save a lot of $$$ in building 100,000 vehicles.
    If the rotors are too light they cannot hold the heat, until it can transfer to the air, without some sort of failure.
    There have been a number of models over the decades with this problem. I knew a guy that worked at a Ford dealer in the 1990s. He told me many of the 1/2 and 3/4 ton pickups were returning for warranty with pulsating brakes. The mass of the rotors had been reduced from previous model years. He said the only thing they could do was install new rotors and pads, true the rotors with an on the vehicle lathe and cross their fingers. Some trucks came back three or more times during warranty.


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