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      10-03-2013, 08:09 PM   #45
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Question Turn crossdrilled rotors?

I decided to pick up the car and see if 6 medium braking sessions would get rid of any deposits and fix the shaking. After 6 sessions the shaking is different but is there it shakes faster but not quite as violent.

At this point I am also thinking the rotors are warped. I am thinking about taking them somewhere to see if someone can turn the rotors for me. I have read this can be done if the person doing it is careful. At this point I dont have anything to lose. Otherwise I just wasted a lot of money on these pads, etc.

Any advice on where to take the rotors?
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      10-04-2013, 03:27 AM   #46
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Quote:
Originally Posted by ccondo View Post
I decided to pick up the car and see if 6 medium braking sessions would get rid of any deposits and fix the shaking. After 6 sessions the shaking is different but is there it shakes faster but not quite as violent.

At this point I am also thinking the rotors are warped. I am thinking about taking them somewhere to see if someone can turn the rotors for me. I have read this can be done if the person doing it is careful. At this point I dont have anything to lose. Otherwise I just wasted a lot of money on these pads, etc.

Any advice on where to take the rotors?
I did not read previous post in this thread but if you haven't already, buy some 900-1000 grit sandpaper, wrap the sandpaper around a small rectangular wooden block, pour some water on the rotors and sand it.

That's how I got rid of pad deposits on my AP Racing 6 pot BBK. So buying a BBK really isn't a solution.

I spent no more than 5 minutes on each rotor. Brought it to the track later in the month and vibrations were gone.

If you're wondering, the pads are Endless CCX. They are relatively high temp rated pads and don't work well when cold. I have since used Pagids and Ferodo which did not give me any problems.

I should also note that apart from the 1 cool down lap 80kph, min to no brake usage, once I enter the pits, I would drive out to the public carpark and do several laps at 30-40kph. At that speed, there is hardly sufficient airflow to cool the rotors down but this is better than stopping and letting 1 section of your rotors fry.

Never had pad deposit since.
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      10-05-2013, 07:14 PM   #47
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Unhappy Tried sanding rotors

TOday I got some 1000 grit sandpaper and sanded down the front rotors and it seemed like quite a bit came off. However it seemed like there were circular grooves around the rotors. IE when dragging my finger straight down on the very top of the rotor is felt like there were bumps or ridges. I know almost nothing about brakes or rotors so I dont know if this is normal or not.

I didnt have time to do the rears but went and drove it and I so far cannot tell that it is any better.

I am planning on sanding the rear tomorrow and if it doesnt resolve the issue or make it alot better I plan on order a BBK.
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      10-05-2013, 11:34 PM   #48
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Quick question, is it necessary to do the bed in process on a brand new M3 with stock brakes for someone not going to the track?

Will it prolong the life of the brakes?
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      10-06-2013, 08:24 AM   #49
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Quote:
Originally Posted by ccondo View Post
TOday I got some 1000 grit sandpaper and sanded down the front rotors and it seemed like quite a bit came off. However it seemed like there were circular grooves around the rotors. IE when dragging my finger straight down on the very top of the rotor is felt like there were bumps or ridges. I know almost nothing about brakes or rotors so I dont know if this is normal or not.

I didnt have time to do the rears but went and drove it and I so far cannot tell that it is any better.

I am planning on sanding the rear tomorrow and if it doesnt resolve the issue or make it alot better I plan on order a BBK.
1000 grit sandpaper isn't going to hurt the rotors. The scratches are normal and will be resurfaced by your brake pads.

To find out if pad deposit still remains, get your brakes up to normal operating temps, find a empty stretch of road where you can safely brake hard from 60-65mph to 20-30mph. If your steering wheel still vibrates under braking, it means the pad deposit is still there.

If vibration is less than before, try using 900-1000grit sandpaper on the rotors.

Remember that after the test drive, don't let your brakes cook again. Drive sedately around sedately for 5-10 mins to let the pads and rotors cool down before you park the car.
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      10-06-2013, 08:26 AM   #50
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Quote:
Originally Posted by swifty View Post
Quick question, is it necessary to do the bed in process on a brand new M3 with stock brakes for someone not going to the track?

Will it prolong the life of the brakes?
Brand new M3 will come with delivery miles on it. I would be keen to know if any of those miles include bedding in the pads. My guess is that they don't bed in the pads.

Maybe someone can chime in on this.
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      10-06-2013, 08:10 PM   #51
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Quote:
Originally Posted by M3 Pilot View Post
Brand new M3 will come with delivery miles on it. I would be keen to know if any of those miles include bedding in the pads. My guess is that they don't bed in the pads.

Maybe someone can chime in on this.
They don't, but honestly for street driving it's not absolutely essential. Yes you get more stopping power if you do, but they're not exactly useless without. And even if you do bed them in, you'll have to re-bed them occasionally because most braking during regular driving is soft enough that the pads will be scraping deposits off the rotors rather than adding more, which is why I don't really bother with it anymore. I might bed in my track pads prior to a track day, but some tracks are set up so you can just use the first couple laps of your first session to do that anyway.

The far more important factor is making sure that you've scraped any existing deposits off of your rotors before switching to a different pad compound.
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      10-06-2013, 08:38 PM   #52
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Something just occured to me

When I cleaned my rotors with sandpaper - I had the rotors on turning them a little at a time. This would only get 1 side the rotor.

Off to find a DIY on how to remove the rotors / calipers etc.
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      10-06-2013, 09:07 PM   #53
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Quote:
Originally Posted by ccondo View Post
When I cleaned my rotors with sandpaper - I had the rotors on turning them a little at a time. This would only get 1 side the rotor.

Off to find a DIY on how to remove the rotors / calipers etc.
It'll be good to have Brake Cleaner handy. They aren't expensive at the auto part store. Give your calipers and rotors a good spray before you start. Do not inhale the brake dust. Spray the rotors down when you are done sanding.

When you head back out for your test drive, do not heat shock your rotors. Slowly build up brake temps by a series of periodic normal braking.

This can be done just by driving around the city as you normally would. You may also want to build up higher brake temps by taking the speed up to 50mph and braking normally to 10mph.

There after, take it up to 60-70mph and brake hard enough just before the ABS kicks in and monitor for vibration in the steering wheel and column. If the vibration is severe enough, you may also feel the front end of the car vibrating.

I hope the sandpaper method works for you.
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      10-06-2013, 09:16 PM   #54
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Quote:
Originally Posted by jphughan View Post
They don't, but honestly for street driving it's not absolutely essential. Yes you get more stopping power if you do, but they're not exactly useless without. And even if you do bed them in, you'll have to re-bed them occasionally because most braking during regular driving is soft enough that the pads will be scraping deposits off the rotors rather than adding more, which is why I don't really bother with it anymore. I might bed in my track pads prior to a track day, but some tracks are set up so you can just use the first couple laps of your first session to do that anyway.

The far more important factor is making sure that you've scraped any existing deposits off of your rotors before switching to a different pad compound.
I tried bedding in my pads at the track in my Evo 9 since I can take it up to higher speed without breaking the law.

All I can say is, brake really early and hold on to your rollcage.

Your initial body senses tell you that the car is not slowing not one bit even when you hit the brakes hard and the wall is starting to look bigger.

I prefer to bed in the pads on public roads because it allows me to cool the rotors down completely overnight. The trade off is speed limitations and finding a straight road with no traffic.

At the track, it eats into my track time as I drive around for about few minutes after 5 hot laps and park it for 30-45 minutes.
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      10-09-2013, 10:48 AM   #55
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I've read the article from Stoptech about the myths with warped rotors. I've experianced warped rotors that were at their minimum thickness limit but on old Trans Am, running a dial guage showed massive variations in the tolerance and also hard pulsating through the pedal. Now I'm not gonna compare that old '76 Pontiac brake system to our M3's but I will say that if these M3 rotors can warp with low miles, track use or not, then how can we explain that the Nurburgring Taxi's, I've been there, rode in them, tracked my M3 there when I was stationed in Europe and also at other tracks in England. Those M3's, M5's at Nurburgring are driving hard and alot of miles put on those brakes lap after lap and they are OEM. Yes, pads are upgraded when I asked about that.

A buddy of mine races here in the SW with his M3 all OEM. Brake fluid and pads are race worthy, I don't remember what pads, but we talked at length about brake vibrations and he is proof that these rotors, with low miles on them relatively, don't distort. He has over 8,000 track miles on those rotors by the way as its only used on the track.

Now, I experianced my brakes (were all OEM/BMW street pads) at plenty of tracks days in England and Germany and I would experiance more of a griddy feeling & noise in my brakes, especially after a summer day's run at Nurburgring. But with a few hundred km of normal street driving, the pads are cool and will work all that pad deposit off the rotors. In the end, I always had smooth brakes.

Ever since I installed a BBK about 2 years ago (not going to mention brand) I've had vibration problems at about 80 mph, never got a chance to track the new BBK until not long ago and have had steering wheel wobble, front end vibration when braking and increases in strength with brake pressure/speed. it's never been the same ever since day one I installed it, and yes, everything is installed correctlyand torqued correctly. Manufacture of the BBk checked everything out on the brakes, done a crap load of testing, BMW checked my front end out and pretty much everything imaginable at the dealership. And still I have the same vibration. which only comes on when braking.

So, I'm going stock again soon to test out my theory. If the vibration is gone after that, then these OEM brakes are damn good. Either my BBK is shit, or my M3 just don't like this BBK or there is something else going on we can't figure out, which I have a hard time believing its something else than the brakes from what I experiance

OP, I seriously doubt your rotors have any problems, unless their warn weay down. Through on some race pads, go for a brake run-in procedure outlined in the Stoptech article and then switch back to your pads and drive normaly for a week or so, then bed them in. Vibration/griddy feelign should go away and you'll have smooth braking again.

Good luck.

Last edited by BimmerRob08; 10-10-2013 at 01:51 PM.
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      10-09-2013, 07:13 PM   #56
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Quote:
Originally Posted by BMW Fanatic View Post
BBK
Do not put handbrake up (our cars go into park once turned off, not like SMG M5)
Bed your brakes in, worst thing you can do is put a new set on and go straight to the track.
Hmmm, so I was told that when parking the car, put it in reverse, pull the handbrake and press the stop/start button. I've also noticed it will go in park if you leave it in neutral and pull the hand brake. So what are you suggesting in order to increase the life of the rotors? I have an 09 E92 DCT btw...
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      10-13-2013, 08:32 PM   #57
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Things are getting better...

So I ordered a StopTech BBK but while waiting I decided to clean the rear rotors to see if it would help or not. Things do already seem like they are getting better. After taking off the wheels and cleaning the outside of the rotors the pulsing is still there but is down probably another 50%.

At this point the outside of the front and rear rotors have been cleaned with 1000 grit sandpaper.

I did have issues trying to clean the rear rotors as they would not spin. I found the instructions on how to take it out of park but they still wouldn't spin. I ended up putting the wheels back on rolling the car back and taking the wheels off again to sand the rotors.

At this point I am tending to agree about the rotors not being warped and it being brake pad deposit.

If anyone has a way of turning the rotors when the car is jacked up I would appreciate it.
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      10-13-2013, 08:49 PM   #58
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Car has limited slip so both rears have to be off the ground. Also emergency brake has to be off?
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      10-14-2013, 04:10 PM   #59
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Quote:
Originally Posted by ccondo View Post
TOday I got some 1000 grit sandpaper and sanded down the front rotors and it seemed like quite a bit came off. However it seemed like there were circular grooves around the rotors. IE when dragging my finger straight down on the very top of the rotor is felt like there were bumps or ridges. I know almost nothing about brakes or rotors so I dont know if this is normal or not.

I didnt have time to do the rears but went and drove it and I so far cannot tell that it is any better.

I am planning on sanding the rear tomorrow and if it doesnt resolve the issue or make it alot better I plan on order a BBK.
Heavy braking sessions with the same pads will only redistribute the pad deposits/transfer. It needs to be removed either by sanding or by more aggressive (track) pads.

The grooves are normal. Mine have them too. It appears to be related to the holes in the rotors. Whatever the cause, bedding in the pads will allow them to conform to the surface of the rotor and they will work fine.

You are on the right track. Sand them all and re-bed the brakes.
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      10-14-2013, 08:20 PM   #60
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Question Should I sand down used BBK rotors

I received my used stop tech BBK and I was wondering should I take the 1000 grit sandpaper and sand down the rotors before I put them on my car?
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      10-16-2013, 08:03 PM   #61
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Quote:
Originally Posted by ccondo View Post
I received my used stop tech BBK and I was wondering should I take the 1000 grit sandpaper and sand down the rotors before I put them on my car?
If you are able to match the caliper, pads, and rotor at each corner the way the previous owner was running them and he had no issues with vibrations, you can throw them on.

Otherwise, I would at least re-bed them. Do you plan to track? Pick up some track pads and run them for a few days to clean up the rotors. Then re-bed the street pads.
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      10-16-2013, 08:58 PM   #62
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Smile Thank you

Yeah I am going to track them. They came with a set of track pads and street pads.

I think I will run the track pads until my event at Barber is over on the 2nd then switch them back to street pads after the event and bed them in.
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      10-26-2013, 08:52 PM   #63
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Are you sure you aren't just over heating the pads? You need to think about your braking technique. I see more beginner and intermediates chew through brakes at a faster rate than some advanced drivers.

By not threshold braking you are putting more heat into them. Thus, increasing the chances of overheating the pads and then all sorts of crazy stuff happens.

How are you cooling the brakes down after a session?

Some pads MUST be bedded in. Pagids are pretty sensitive to being bed in. PF01s can just be installed and then driven on if installed after OEM or ST street pads.

Quote:
Originally Posted by lcrain View Post
I have heard that too about the 01 on rotors. I will certainly keep an eye on them. I love the way the PFC 01 bite, but I only have 3.5 days (days, not events!) on them and they might have 2 days left if I am lucky.
The 01s don't eat rotors when used as intended. They eat rotors if you use them in cold weather and never get them up to temp. PF01s DO cause a more than average heat cracking.
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      11-13-2013, 10:59 AM   #64
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I have exactly the same problem with vibrations as described by ccondo. The cause of vibrations was also exactly the same, track session with stock brakes and pads. On top of it, this track (Zolder) is known brake killer as you need to break from around 180-200 km/h to 50-70 5 times in 4km.

I was reading this post with great interest and tried all suggestions. I installed better pads (Project Mu HC+) to try to scrape pad material of the rotor. Did not work!

Then I took the brakes apart again and used sand paper on rotors. 1000 grid did not remove almost nothing, so I used coarser. After that I finished it with 1000 and later with 2000 to polish everything up.

Again the same problem with vibrations. No influence.

After that I was running HC+ pads for additional 1000km, I was also on the Nurburgring where I did little bit of more aggressive braking. Since it was wet it was not really aggressive. But it should be enough to scrape pad deposits, if any!

Same s..t! I still have vibration.

I had similar situation with my old 330i after track days with vibrations. But obviously in that car I really had pad deposits as vibrations were gone after some time.

This time not, so for sure my rotors are warped!

What a great car BMW made. It is juts perfect in all aspects, except the brakes. They obviously know the issue as they will offer ceramic brakes in new M4, also they are starting to push heavily performance parts for other models that include BBK.

Bye bye OEM brakes, I am getting AP Racing!

Not worth spending money and my nerves on new pads, fixing this problem and potentially new rotors!

EDIT: Believe it or not my brakes fix them selves after 3000km of running Project Mu pads. So after all, all the gents suggesting brake pad deposits were right!!!
But it took me awfully long time to scrape that off the rotors.
BTW still getting AP Racing!

Last edited by krx927; 12-26-2013 at 06:41 AM.
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      12-06-2013, 10:56 AM   #65
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Why wouldnt you just have the rotors turned/resurfaced if there is plenty of meat left? It's a misconseption that you have have drilled rotors turned, you can.

My drilled rotors from Turner were warped on my 330i after a couple track days. I called Turner, they said no way, its pad deposits. So I did another bed in proceedure, the shimmy was still there, so before the next hpde I took the rotors off, went to a small local mechanic shop and had the rotors turned. Sure enough, when he put them on his lathe, you could see a visible wobble as the rotor went around. Bolted the car back together (with fresh pads) and teh car felt great at the track and hasn't had any pulsation since.
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