jus experienced some vibration at speed above 100

[4drmadness]

hey guys, i was jus racing a bmw 535i and 335i, both kinda owned me lol, but thats not the point. well after getting headers and a tune, i will show them whos boss. when i was going at speeds above 100, and then braking, i felt a lot of vibration coming from the brakes. i have about 10% life left in the front brakes and i am gona replace them next week with hawk hps. my question is are my rotors warped? or can i just resurface them? thanks for your help. Bimmers FTL

[johnparkyourcar]

rotors would be my guess. today when i was driving down macarthur there was a e46 m3 to my left and a e92 m3 to my right both did a ricer flyby .

[zozoka1212]

Yeap the rotors are warped. Try to resurface them.

zozo

[tollboothwilley]

ding ding

Thats why the stock rotors/pads aren't a good combination for me.

I warped 2 sets or rotors with really nothing unusual in my driving style. Since I put on these X drilled/slotted I've had no problems at all.

[4drmadness]

alright this time ill resurface them, and next time i will def get the drilled/slotted rotors

[SVTCOBRA]

Mine are warped on the 05 Sedan with only 30K miles....And it hasn't been driven hard. and the wheels have been torqued to specs since new....

[SteveTheTech]

Mine are warped on the 05 Sedan with only 30K miles....And it hasn't been driven hard. and the wheels have been torqued to specs since new....

This is one of the most overlooked causes of lateral runout. Hard high speed braking where the rotors heat excessively will also cause visible blue spots if it severe enough and that cannot be resurfaced due to inconsistency in the material composition.

Vivek- please measure the rotors before you resurface them. If there is a lip on the outer edge of your rotors I would be willing to bet you will need to replace them. The spec for the original Gs is ~0.880" that is the repairable limit, and we usually will not resurface anything that is <0.900". You will need about 0.020" of machineable surface to "cut out" your pulsation. If you were to cut the rotors then you would be almost guaranteed to be at the serviceable minimum diameter and you would not want that.

Just some food for though.

[4drmadness]

alright i see, i will check to see if i have the lip in the outer edge

[kmckis1029]

will the dealershisp install aftermarket rotors? or aftermarket parts at all?

when i do my next brake service i want to upgrade my rotors to slotted/drilled...

[G_whizz]

will the dealershisp install aftermarket rotors? or aftermarket parts at all?

when i do my next brake service i want to upgrade my rotors to slotted/drilled...

I believe they will and warranty the work if I'm not mistaken (not the parts)

[SteveTheTech]

I believe they will and warranty the work if I'm not mistaken (not the parts)

Not at my dealer, we do not warranty any aftermarket parts. From the other side of the fence it is very hard to stand by products that are not from the factory.

I understand that there are some parts out there that have superior results (by this I really only mean early G brakes, for the sake of this discussion), but they tend to make noise and they may casue a pulsation. If you have a pulsation with slotted/drilled rotors that developed lets say a week after your brakes were installed the dealer has to buy you new rotors? It's not worth the hassle for many dealers to install aftermarket things.

Now that's not to say if you have a good relationship with the dealer personal and understand they most likely will not be able to warranty the parts, they may be able to help you out.

There are tons of dealers out there who sell aftermarket parts and if they can make a profit on them and have techs who know how to install and calibrate them properly I would go that route. One of the Acura I went to would sell intakes, exhausts and other power mods but would only install things that you bought from them directly.

[Jacko3]

Surprisingly, my dealership would install anything for you. The only thing they seem not to like is the installation of headers and maybe testpipes. However, they replaced a faulty flywheel for me under warranty with almanner of mods on my car. I guess dealerships differ on what they will or won't accept when the car is under warranty.

[kmckis1029]

thanks for the info

[Tampa G35 Sedan 6MT]

I have the same problem with my sedan... I need to put new Rotors on. I might go with slotted or cross drilled but im not sure as you can't resurface!

[tollboothwilley]

The only reason you need to resurface rotors is if they have hardened areas. X drilled/Slotted rotors will allow for better cooling properties. When you put new brake pads on you can just rough up the surface a little by using some 400 grit sandpaper if you want. That will help the bed in process.

[SteveTheTech]

Surprisingly, my dealership would install anything for you. The only thing they seem not to like is the installation of headers and maybe testpipes. However, they replaced a faulty flywheel for me under warranty with almanner of mods on my car. I guess dealerships differ on what they will or won't accept when the car is under warranty.

It seems like you have found some place interesting, I do not know if I would perform this type of work. I prefer fixing logical problems and I am not a tuner. Diagnosing a fault in a vehicle with numerous components that do not perform in the same manner as the original is a challenge that many technicians will not touch at all. When it comes down to it it is more about the tech and the policies of the shop.

For most dealers the pros just do not outweigh the cons. Audio and electrical "upgrades" usually pose the biggest challenge to fix and problems that may stem from product failure, improper interaction with other devices, or improper installation.

[Sentientbydesign]

I have the same problem with my sedan... I need to put new Rotors on. I might go with slotted or cross drilled but im not sure as you can't resurface!

You can resurface them, it's just not recommended. Also, many of the aftermarket rotors are more durable than the factory (there's a reason for the factory rotors to be soft). With the more durable aftermarket rotors, you don't deal with the uneveness and scoring.

[Jacko3]

OEM rotors work well--they grab excellently even when they start fading. I have turned my OEM front rotors twice, inspite of all the flogging I have been giving my car. The only problem with oEM brake stuff is the pads---the wear out extremely quickly----too soft. I am now changing front pads every six months or less.

[SteveTheTech]

The only reason you need to resurface rotors is if they have hardened areas. X drilled/Slotted rotors will allow for better cooling properties. When you put new brake pads on you can just rough up the surface a little by using some 400 grit sandpaper if you want. That will help the bed in process.

I don't know about you guys but I always turn the rotors (if there is more than 0.020" before discard). I learned a long time ago trying to be lazy only produced a inferior brake job. If you follow the correct procedure and do it correctly it will be like having new rotors. I do not understand why anyone would want to use a new brake pad surface on an existing finish for another set. Having the chemical transference that occurs between hot pads and rotors.

Mmmm the physics, I want a fresh mating surface to let the new pads break in with a fresh non directional finish. I've tried it both ways and not machinging just does not provide the best results. I As a side note if you reuse the stock rotors on an early model G with any pads I will bet you are running unsafe rotors.

Think about it this way....Your driving down the highway on your way to work, you momentarily look down to grab your coffee cup and once you look up and there is a Ford Escort in front of you now with their brake lights on and the car is nose diving you have < a second to decrease your speed. Do you want to wonder? I don't mess with brakes on my personal car, anything my family and myself rides in I want to trust my work and the products I use.

[Sentientbydesign]

I've done quite a bit of research regarding brake pads and rotors. The concensus (from experts) is that rotors only need to be turned for excessive runout, warpages (I'd toss them if they warped), or when changing pad compounds.

If you're keeping the same compound and the rotor is in good condition, then the rotor will already have the same compound on it and break-in MIGHT actually be quicker.

My personal experience with turning powerslots is that I loss a tremendous amount of brake force afterwards. Prior to turning (even when they were brand new) they had a lot of grab with even light pedal pressure. After turning (with the same, but new set of pads) it felt like the rotors were glazed and required a lot of effort to stop.

[4drmadness]

wow this thread is getting way too confusing. i saw a lip forming on the outer edge. but still not decided if i wanna jus get x drilled/slotted rotors or just resurface these. btw resurfacing can work even if rotors are warped?

[4drmadness]

hey steve, i have around 66k on my car. u think i shud change the brake fluid? any thoughts?

[SteveTheTech]

wow this thread is getting way too confusing. i saw a lip forming on the outer edge. but still not decided if i wanna jus get x drilled/slotted rotors or just resurface these. btw resurfacing can work even if rotors are warped?

Sorry to rain on your parade Vivek but resurfacing is not going to work for you in this case. Since you see a ridge around the outer edge of the rotor on stock rotors I would be willing to bet you they are done.

Look into getting something like Brembo blanks can't mess with Brembo for normalish use. And they can be resurfaced. The Gs that were equipped with the Brembo option had no issues with pulsation through the life of the pads from what I have experienced. The stock pads would last 40-50K and in most cases the rotors could be resurfaced allowing 90K out of one set. Not bad considering the factory ones retail for $150/ea.

EDIT-I would change the fluid if it were dark. You only purchased the car recently and in most cases that would have been changed already depending on how much they had in your car.

Before changing any fluid get the history of what has already been done. There is no need to waste money.

[4drmadness]

alright thanks for your help.