paperboy42190

iTrader: (7)

So I've been having an issue with vibration while braking. It only happens when going at least 50 mph. It's not horrible but I think it's noticeable. Started happening like 3 weeks after I installed brand new R1 rotors. Most people I ask seen to be R1 fanboys and say since its made by centric it cannot be warped in 3 weeks. I don't track the track but do spirited driving. Others say its improper bedding. The problem didnt start until 3 weeks after I got the rotors. But I tried it anyways, took off the rotors, sanded them and reinstalled. Didn't help. I chased down every cause and cannot find a solution, is it possible it's from some suspension component? Keep in mind it's ONLY when braking at over 50mph. I'm very tempted to just buy a new set from autozone.

makk

Just because they are new doesn't mean they are perfectly true. Either buy new quality rotors or get the R1s machined by an on cae lathe.
Also, what pads are you running? Some pads leave heavy deposits on rotors in as little as three weeks.

supraru

90% of the time it's not the rotors causing the vibration it's the pads. What kind are you running? I had monroe pads on my TL when I purchased it with about 9/32's left. I drive like a normal person now and within a week they were pulsating. I just spent $100 and got oem pads and cut the rotors. So far so good.

makk

That is incorrect Suparu. The manual has runout specs for the rotor not the pads. How can pads cause vibration? They are fixed not rotating.

supraru

For one I am a mechanic, so I'm not just some kid taking a guess. Rotors have runout specs yes. There really isn't such thing as a "warped rotor". What actually happens is depending on the pad used the material can transfer from the pad onto the rotor. Doing so causes vibrations.

Now for the other way to look at it. Some cars like sti's, evo's, or I'm sure even type-s's that run more aggressive pads tend to not only wear the pads but slowly chew up the rotor.

The crap aftermartket monroe pads that were on my tl are generally known to chew up rotors. They use a more metallic compound that does this. This is why I went with oem's. I could have bought aftermarket pads and taken a chance at getting them a couple bucks cheaper but I have no interest in making this car a race car or drive it hard so there is zero reason to stop faster.

supraru

Here you go. Take a read at this and you'll understand my comment.

http://www.examiner.com/article/ther...d-brake-rotors

supraru

Not sure how I didn't see this. You just described what warped rotors are. You knew it all along but didn't realize it.

makk

Bingo.

supraru

While you described it you still don't really understand. You pretty much stated what the issue could be but when I said the pads are causing the warped rotors you questioned me even though you already stated it. I'm just glad I could educate you a little more.

makk

I understand it thanks. Rotors can warp from repeated heat and rapid cooling cycles. Also some pad material embeds on the rotors.

makk

We are arguing the same thing I guess. I understand the concept of pad material on the rotors but my assertion was it is the uneven rotor surface causing the vibrations.

supraru

I wasn't arguing anything. I was stating what most likely is the issue. You disagreed even though you said the same thing I explained. Not sure as to why you would do that. lol You said what I explained wasn't true and asked how pads could cause vibrations when you explained how already. Split personality or is two people using your name? hahaha. No harm man.

ZOMGVTEK

Checking the runout when installing new rotors would put this to rest. You'd be sure the rotors are true on installation, and any vibration would be uneven deposits most likely caused by improper use/compound, or actually warped rotors.

Vibration can most definitely occur with new or nearly new rotors.

supraru

I'm sorry and I'm not trying to sound mean by saying this but you have no clue what you're talking about or even how to measure run out or what it means. They are new rotors....the run out is zero.

paperboy42190

iTrader: (7)

I have stoptech brake pads with approx 50-60% padding left. so what do you guys think I should do? put it on a lathe?

Turbonut

iTrader: (1)

The only way to get rid of the pulsating is to have the rotors cut, or purchase new rotors. As most will cut the rotors without any thought as to thickness specifications, make certain you mic the finished thickness to be certain it's within specifications.

supraru

Depends on what you wanna do really. I ran the pad above the carbotech bobcats. Put them on and cut my rotors. Bedded in the brakes the best I could for driving on the main roads. Less then a week I had to cut them again. Then another week later I had to cut again. After that I had no issues after that.

Don't worry about thickness with getting new rotors cut. There is tons of meat left on the rotor.

I hate cars

I didn't want to bring this up but I also have pad deposits causing a very slight vibration on brake application at high speeds. This started after a month of very easy driving and after a couple hard high speed stops and being forced to stop at a light immediately after. I put it in neutral with the brakes off but still got some deposits. Part of the problem here is I drive it very easy, the larger rotors run quite a bit cooler than OEM and with the colder temps I don't have a proper transfer layer as is evidenced by the squeaking. I've run a full race pad on the street so I'm used to this sort of thing. I'm going to do the breakin procedure over again in about 30 minutes. It should scrub down the high spot and put down an even layer. I might have to start driving it hard occasionally.

I hate cars

I hope I didn't go overboard, I have blue rotors lol. I drove it for about 5 miles for cool down. After parking it in the garage and feeling the huge amount of heat coming from the brakes I kind of wish I had gone 10 miles for cool down. No vibration but well see in an hour or so. It usually takes 2 times to get rid of pad deposits.

supraru

Sounds like your brake system is way over kill for an acura Tl. I ran some pretty intense track pads on my Rsti. Not only did they squeal like crazy but get them warm and the car stopped on a dime. Long story short they were put to use once when I first got them. After that it was just daily driving and an occasional spirited drive. The rotor was completely trashed after 9 months. Not trying to tell you what you should have and shouldn't have but track pads on this car is unnecessary.

Turbonut

iTrader: (1)

Don't know where the tons of meat comes from as the base TL only has a total .08" (.04" ea. side) wear before they are under spec and the Brembo's .07", rears .05" wear. Of course one can cut the rotor to any depth and ignore the specs as is often the case with the part houses.

I hate cars

I had track pads with my old Rotora BBK but I currently have an ordinary high performance street pad that comes with the Stoptech BBk. I drive extremely easy and many times for a week or two the car might only see the 1.7 mile drive to work that usually consists of just one stop on the way there, maybe 3-4 easy 35-40 mph stops. Very easy use. Starting tomorrow it will be a 20 mile in town trip along with a 45 mile drive each way including some fun downhill twisted so for the nex 20 days I shouldn't have to worry too much about the brakes being too cold and never getting hot enough to lay down a transfer layer.

I used to track the car and even with 13" front rotors it required a race pad or I had to drive around the brakes. Even though its not a powerful car, with that much weight up front, 13" brakes are far from overkill at the track. I no longer track it but the whole purpose of the BBK is to be able to run a well mannered street pad and still have fun on occasion in the twisties and not worry about fade.

I love these rotors for a 1pc design and the calipers are stiffer than any street caliper I've run, no worries about deflection. The brake bias is retained and judging by rear rotor temp maybe more rear bias over stock. With the tires fully hot and this brake system I've got stopping distances in the bottom 90' range so it's capable of putting a lot of heat into the brake system. Maybe the weak link is the pads. My initial impressions were great. As time goes on I might try something else if driving harder doesn't work. This car is right at 3700lbs without me in it due to the additional sound deadening and audio equipment so that's 3940lbs. She's a pig. My other car gets away with 10.8" front rotors and drums on the rear even at 602rwhp but its barely 3,000lbs. It has roughly the same fade resistance as the TL probably because of the 700lb weight difference. I don't want to make this about my BBK, hopefully the OP will get the help he needs. I just wanted to add some details about my situation, maybe it will help someone even with stock brakes.

supraru

Not sure where you're getting your info but check out the numbers in post #4

https://acurazine.com/forums/3g-tl-problems-fixes-114/need-hard-number-rotor-thickness-brake-pads-dealership-dishonest-830717/

Standard new rotor measures 27.9 to 28.1mm. Minimum spec is 26mm. That is a at minimum 1.9mm of cutting. If you haven't cut rotors before then it's understandable that you don't realize how much rotor that is. On average When I make a pass to cut a rotor I will remove aprox .02mm from the rotor. In most cases I make only one pass. Only time I make more passes are on really rusted rotors. Theoretically I could cut a brand new rotor 9 times before it reaches minimum spec.

I hate cars

Agreed. Being so OCD I have trouble with even a "cleanup" because it will downgrade performance even if its not measurable.

I think it's a shame that so many places cut the rotor when all they have to do in many cases is just barely touch up the rotor.

supraru

Fair enough. Each car is different and I'm coming from a 2700lb car. Each pad is different as well. Like I originally said some (like most stock subaru's) don't eat up rotors with stock pads, minus the sti which after you go though a set of front pads can be cut but will be right at minimum spec. Some aftermarket pads like the monroe's that we've seen people put on are just a stock replacement and eat up rotors. It all depends on the manufacturer and how they make pads. More aggressive pads will always eat rotors.

Also it boils down to driving style. Sometimes you just can't avoid having to break hard and stop fast. Usually when I have to I try to stop sooner then I have to so I can continue to keep moving instead of letting the pad bake onto the rotor and possibly causing vibrations. There are just way to many factors in the whole thing.

getnbze

So your saying if he changes only his pads this vibration will go away? and that a rotor can not be warped?

I hate cars

Rotors can warped but in most cases it's pad material getting deposited and baked onto one area of the rotor causing a high spot. Getting the brakes good and hot and the. Sitting at a red light is a good way to cause this.

Once you have uneven deposits you usually have to get the rotor cut to get rid of them. Some people will run a very aggressive track pad to get rid of the high spots to basically wear them down. I've had some luck with doing an aggressive break-in procedure sometimes 2-3 times. Sometimes not.

The rotor is supposed to have a transfer layer; a layer of pad material on the rotor so the pads are rubbing on pad material and not so much the rotor. This usually gives a higher coefficient of friction and less rotor wear. In some cases it can also lead to lower rotor temps. You have adherent friction which is what you want where you have the pads acting on the transfer layer of the rotor. You have abrasive friction which is the pads grinding on the rotor itself causing more wear and heat than adherent friction.

Rotors should not be shiny. My rotors when using a race pad on the street looked like chrome because there was no transfer layer because the pads never got hot enough to lay down that transfer layer. It led to SEVERE squeaking that would scare people next to me at 70mph on the freeway. They didn't work that well when cold. They absolutely destroyed the rotors with premature wear and what looked like excessive heat.

paperboy42190

iTrader: (7)

thanks for the advice guys, I will have my rotors cut this weekend and report back

supraru

Well yes and no. For one you always wanna cut the rotor when putting on new pads. This lets the pad material and rotor basically start fresh. If you have say one pad and you just slap on a different pad your breaking can be affected. It could be a little or a lot. So a direct answer no he can't just change his pads and it'll go away. He can get them cut and keep the pads or cut them and get different pads. In the end you can "warp" and rotor with any pad. Just some aid it more then others.

Turbonut

iTrader: (1)

From the FSM and #4 is the exact same numbers I've posted so???????

If you only cut .02mm from a rotor, do you realize that is only .000787", or .00039354" from each surface, about 10 times thinner than the human hair? Sorry to say, but no wonder why you believe there is a ton of meat on the rotor.

I've cut many rotors and have had many rotors cut when not having access to the lathe and you know what I've observed, not one time did the shop or garage ever mic a rotor. The rotor was put on the lathe and when the bit made full surface contact, the cutting began, or if the surface was grooved or in poor condition, multiple cuts were made. The rotor could have been cut previously, but no one seemed to care as it was easy money in their pocket to do the cutting.

Most would be better off purchasing new rotors if more than a very minimal pass is needed.

supraru

Sorry, don't know why I put .02 but my math was right. I cut .2mm with one pass. But either way I could cut a new acura rotor 9 times before it reaches minimum spec. I really don't understand your point. You're using hair thickness and trying to turn it into well a hair is extremely thin which is the wrong way to look at it. When I cut a rotor I'm not saying how many tiny hairs am I cutting out today. I measure the rotor thickness and compare what I will be cutting out compared to minimum spec. If it's a brand new rotor measureing at 28mm and I make a .2mm cut there is still a lot of rotor to go until it reaches mininum spec.

Are you sure you have cut rotors before? The way you talk you sound like you have zero clue on the rotor cutting process besides measuring a rotor for thickness.

Here's an example for you and I can only speak for myself and people I work with. The only time I mic a rotor is when it is waranty and they need specs, or when I see the rotor is getting thin. Being that I work for a subaru dealer all I see is subaru's. Their rotors start out life right around the 28mm just like acura but their front rotor min spec is 22mm. So subaru has even more acceptable "meat" that is allowable to cut out. When I check out a car I look at all these things.

Most wouldn't be better off buying new rotors. Really it's just a waste of money to do so. I appriciate your input to the thread but your train of thought or expertice on the matter is extremely lacking therefore bringing down the actual fact content into this thread for real life help to users. I do this for a living. As glorious as that sounds it really isn't, but I do know how to do my job. Just because you may have done it once or twice and saw it done doesn't mean you have a clue what you're talking about.

I'm sorry to come off this way but when trying to help someone out there is no need to put out bogus info like you're doing.

Turbonut

iTrader: (1)

Hey, you copied my post and said not to worry about cutting the rotor as there is plenty of meat available, enough for 9 cuts. You know absolutely nothing about me or my experience, and doing it for a living means nothing as you had better check the Subaru rotors. On the WRX STi new 30mm front 20mm rear and the service limit is 28mm and 18mm and that is only 2mm, very similar to the TL at 1.9mm. Don't know of any rotor that gives a 6mm tolerance, so if you cut 6mm as stated, good luck. Now that we're down to .2mm per cut, that equals .003937" per side which is still thinner than a human hair.

Talk about bogus information, just give up.

getnbze

Agreed

supraru

I know one thing and that is its clear you have next to no automotive knowledge and I'd even go as far to say you've never cut a rotor before. This isn't my first time dealing with someone who pretends to know what he's talking about.

Again explain why you keep comparing a cut to hair? I see what you're trying to do and why but your point is to only be a douche and has nothing to do with the act of cutting a rotor.

That's neat, you can compare a stock base tl rotor to an sti rotor. Again your lack of automotive knowledge shines in this comparison. I know why it does but find it hilarious that you can't see why.

Dude you have no clue what you are even arguing. You are just arguing to argue. Your petty attempts at trying to sound knowledgeable is just silly and does nothing in helping the op.

supraru

And then there were two people in this thread that have no clue what they are talking about.

I hate cars

If you're swapping pads of the same brand and type, there's no reason to mess with the rotors. Usually just following a semi-aggressive break-in will be sufficient to get rid of the old pad buildup and deposit the new transfer layer when switching brands/type. FWIW, I don't cut rotors and I don't replace rotors during a brake pad change unless the rotor is out of spec. Time alone will fix any problems which are unlikely in the first place.

Where I agree with you is if I were doing this for a living on customers cars, I would cut or replace rotors during a pad change but only if the new pads are of a different type than the old ones just to cover my ass.

I can remember back when I was young and poor and could only afford pads, usually what was cheapest and I always used different pads without touching the rotors. Its not the best practice but most of the time it won't hurt a thing. I also remember not having the money for a set of pads and wearing through the pads and having the pads packing plate wear all the way through the rotor and into the vents in the center. That was fun lol.

paperboy42190

iTrader: (7)

looks like I started a big debate about rotors. I always knew it was a controversial subject as different people I ask sometimes strongly gave different opinions.

getnbze

Oh but see you dont know who I am and you dont know my experience either. I've actually enjoyed sitting back and listening to you, you quite hilarious.

I hate cars

It is controversial but if everyone had correct info it would not be. I've done a ton of my own testing, I'm a nerd like that. I have stopping distances from every setup I've had, rotor and cliper temps with every setup in many different scenarios, and a lifetime of changing brakes and tracking.

Some of my personal experience wsa backed up by google, some was not. What I finally did was purchase a few SAE studies on brakes plus EBFD to put all of these rumors, theories, and myths to rest. There are so many variables and it's easy to assume what caused what but sometimes the answer isn't obvious. Many "pretty" websites are quite wrong, you have to be able to detect BS and sometimes it's hard. Stoptech is a great resource if you're interested in brake basics. It gives a great foundation.

getnbze

Yes it is very controversial. I too have done alot of testing on the sublect. Considering that it was part of my job at Honda R&D on the 3rd Gen platform as well as many others at R&D. My recommendation would be if the car is stock then put OE pads and rotors on it and be done with it. There was alot of research that went into the OE parts