What does it take to fix 135 front brakes?

[MrBlonde]

AP Racing is your friend!

[pixelblue]

AP racing offers a solution for e82?

[mpatrone]

Originally Posted by redrum36

Do I need to go to Stoptechs? My pedal goes to floor on track. Fluid is srf. Something is wrong or the brakes just suck that bad? Hawk 70's not lasting long and very uneven wear. Inside pads thin plus tapered toward "top" and trailing edge too. Where's the cheapest place for ST40's?
Thnx

I think you answered it yourself. Stoptech Brake Kits...

After talking with several experts and going through this problem myself, two major flaws are apparent.

1. The size of the OEM Brembo calipers and rotors prevent proper cooling
2. BMW failed to provide adequate cooling for the brakes

The stock brake calipers not only soak up heat, but are too narrow to allow for any decent aftermarket rotor upgrade (like 2 piece slotted) to fit with new pads.

Those using any type of race pad (Hawk DTC70 in your case) with the stock brakes will most likely experience problems during hard braking at the track. The heat produced from race compound pads is getting absorbed by the calipers and going directly to the fluid, which is why it seems that you're getting fade so often. You are probably just boiling the fluid every time you go out bc of inadequate cooling.

Important note from Stoptech that also applies to OEM Brakes:
problems occur if pads are not properly bedded-in (an even layer of pad material on the rotor) and are run aggressively, OR if the pads are overheated (street pads on the track like we tell 37 people a week NOT to do). If you have a high performance pad and never run it hot enough to get a proper layer of material onto the rotor, it will never be properly bedded-in. Thus, even after 1000 miles of "normal" street driving, when you blast your favorite canyon and heat the brakes, you can get uneven deposits on the rotor causing a vibration. The other common scenario is over-heating the pads even if they are properly bedded-in. In this case, the pad material starts to break down and smear onto the rotor face, again causing the UN-EVEN deposits.

Make sure that if you are using the same rotors for street and track pads, that you put the track pads on a few days before, and use the abrasive nature of track pads to grind the bedded street pad off the rotor. READ THIS ARTICLE AND WATCH THE VIDEO IF YOU SWITCH BETWEEN STREET PADS AND TRACK PADS ON THE SAME ROTOR
http://www.essexparts.com/learning-c.../swapping_pads

I too recently got the Stoptech ST-60 kit, but still experienced problems with cooling (refer to my recent thread). I was running Hawk HT-10s, which HAVE A MOT somewhere around 1300F. I experienced a catastrophic failure with one of the pads, which pretty much split in half.

Point is, for cars that go as fast as ours and weigh close to 3300lbs, you need serious pads (Carbotech XP10/12, Hawk DTC 60/70, PFC 01/06 etc) which cause lots of heat. One needs proper cooling to keep the brakes working at their best, which the Stoptech/Brembo BBKs improve by providing rotors that are thicker and have larger diameters. Furthermore, they are 2-piece rotors, some with vanes for additional cooling.

Everyone mentions the "brake ducts" in the 135i or in the BMW Performance bumper, and while these do provide extra air to the wheel well, they don't come anywhere near the performance of a proper brake duct kit. For now, all we can really do is change the fluid before each event, and either do the DIY splash guard mod or pay for a custom brake duct kit.

[N55_BBM]

Originally Posted by adrean8j

Normal and typical...had this happen with my old E39 and with my E82...pads are fine, rotors are fine....that being said I think it has something to do with outdoor temps and pad temps(this by no means is definitive and just a guess). Does it go away eventually or does it sound like that when the car is fully warmed up (as in driving around town for 20-30 minutes?)

Nope still squeals (or chirps whatever the thin annoying noise is lol) after a 40 min commute with varying speeds up to 70mph and varying breaking loads. I don't know that it's "normal" because it's never done it up to now. Could it be worn brakepads?

I could have yet another item on my "to fix" list for my upcoming service, oh lord...

[The HACK]

Originally Posted by redrum36

I had similar issues. Replaced fluid with SRF. Next time out, same pedal to the floor crap. Never experienced this before in my 150 track days. i am running SRF AND hAWK 70'S. The pistons are not going to fix this problem. it is a cooling problem or the pistons wouldn't shatter in the first place. The freakin rotors are too small for the calipers. I had st40'swith 355x32 on my e46 m3 with brake cooling ducts. that really helped. With this car, there is hardly any room to get ducts in there and nothing available to attach them too. After 12 years of BMW's I am feeling frakked by them. I should have bought a Lotus or Mustang. I will be buying stoptechs and selling the 135 brakes. BMW doesn't even have a part number for the caliper reting bolts wich should be replaced every time the calipers are replaced, which is every time we change pads! WTF! One of my bolts backed out and bent the other, That's how i found out about that, BMW still does not have a fix for that either.

There you go. You have a car that weighs nearly the same as an E46 M3, nearly the same power (if stock) with more torque, but rotors that are over 1" smaller in diameter all around. So both cars are capable of generating the same kinetic energy prior to a braking zone, but the 135i is clearly inferior in its capability to dissipate heat.

Simple math would indicate that there's simply not enough heat capacity in the braking system, period. Larger rotor or more efficient cooling is the key here.

[redrum36]

I installed Stoptech STR60's with 355x32 rotors. They feel much better. 1st track event with them is Monday. We will see. I think they will be good. I bent the backing plate but did not cut the bottom of it yet.
When I first changed them they still felt like the OEM's and I was thinking WTF and what else could be wrong? THen I remembered that I need to bleed the INSIDE as well as the outside of the calipers! Then everything got great! I am thinking that all of the brake flushed etc may have been neglecting to bleed the inside of the calipers because other BMW brakes don't need that. Just a thought. I can't imagine that those big brakes could be that bad. THat's what I am thinking.
I have a couple of ideas on how to get cooling in but haven't done it yet.

[N55_BBM]

Originally Posted by N55_BBM

Nope still squeals (or chirps whatever the thin annoying noise is lol) after a 40 min commute with varying speeds up to 70mph and varying breaking loads. I don't know that it's "normal" because it's never done it up to now. Could it be worn brakepads?

I could have yet another item on my "to fix" list for my upcoming service, oh lord...

so following up on this issue... I had to bring the car to a stop from autobahn-like speed this weekend (not an emergency braking, just to slow it down, take an exit and stop at a stop sign).. and it was a bit scary actually. took a lot longer to brake, and towards the end the pedal did shake a bit. I've had to stop it at that speed before and have experience on the track, and it usually stops a lot better. There's nothing wrong with the pedal feel since I bled the brakes actually, it's just that the pads aren't grabbing the rotors wit has much strength.

I'm pretty sure I'm driving on very worn-out brake pads. Taking the car in for service next week.

[N55_BBM]

just wanted to follow up again on my brake issues if anyone cares / is following this lol

took it into the dealership for regular service, pads and rotors are fine. actually, I still have 2/3 of the pads left.

what I can recall from my conversation over the phone (it was difficult since I don't understand much about this) was that my backing plates had to be repaired, my damping layer was replaced because it burnt off, the pads were tapered and they cleaned the edges where that happened, lubed the calipers up and realigned and assembled everything back. they say the brakes work fine and doesn't squeak now.

my SA started laughing and said that it's not a matter of my brakes being worn, it's just that i'm braking way too hard and way too often and it's overheating everything there. guess this is further proof how the stock brakes in this car cannot withstand a track day not because the brakes suck, but because they aren't cooled properly...

i'm picking my car up tonight. sick of that 328 loaner i got already and it's only been 24 hours.. lol

[pixelblue]

Originally Posted by N55_BBM

just wanted to follow up again on my brake issues if anyone cares / is following this lol

took it into the dealership for regular service, pads and rotors are fine. actually, I still have 2/3 of the pads left.

what I can recall from my conversation over the phone (it was difficult since I don't understand much about this) was that my backing plates had to be repaired, my damping layer was replaced because it burnt off, the pads were tapered and they cleaned the edges where that happened, lubed the calipers up and realigned and assembled everything back. they say the brakes work fine and doesn't squeak now.

my SA started laughing and said that it's not a matter of my brakes being worn, it's just that i'm braking way too hard and way too often and it's overheating everything there. guess this is further proof how the stock brakes in this car cannot withstand a track day not because the brakes suck, but because they aren't cooled properly...

i'm picking my car up tonight. sick of that 328 loaner i got already and it's only been 24 hours.. lol

this is what everyone was trying to tell you in so many words. also there is nothing wrong with the brakes it's just your braking technique. last weekend a pro driver took my car around summit point and set a blistering pace. afterwards he told me how great the brakes were. actually in an earlier session while he was driving we had a mishap and the brake pads were literally on fire and had to be extinguished. took a few cool down laps and we were back hammering down the track. keep in mind I am running R comps which are actually tougher on the brakes

[GeeRam]

Originally Posted by pixelblue

AP racing offers a solution for e82?

Not directly.

But, you can buy 1er specific kits that use AP Racing products.

Birds Tuning here in the UK sell a BBK for the 1er, that uses AP Racing components.

http://www.birdsauto.com/content/col...8734870500.pdf

[terivera]

Originally Posted by redrum36

Do I need to go to Stoptechs? My pedal goes to floor on track. Fluid is srf. Something is wrong or the brakes just suck that bad? Hawk 70's not lasting long and very uneven wear. Inside pads thin plus tapered toward "top" and trailing edge too. Where's the cheapest place for ST40's?
Thnx

rebuild with stoptech pistons $560.00

[Focusedintntions]

Get some ducting too

[mbintx]

Originally Posted by pixelblue

this is what everyone was trying to tell you in so many words. also there is nothing wrong with the brakes it's just your braking technique. last weekend a pro driver took my car around summit point and set a blistering pace. afterwards he told me how great the brakes were. actually in an earlier session while he was driving we had a mishap and the brake pads were literally on fire and had to be extinguished. took a few cool down laps and we were back hammering down the track. keep in mind I am running R comps which are actually tougher on the brakes

Great point. I wonder how many of the 135I brake problems are due to people "street braking" on the track instead of using proper technique. I'm sure correct braking won't cure ALL of the braking ills, but might help prolong brake life during a track session.

[Spitfire007]

Originally Posted by mbintx

Great point. I wonder how many of the 135I brake problems are due to people "street braking" on the track instead of using proper technique. I'm sure correct braking won't cure ALL of the braking ills, but might help prolong brake life during a track session.

So, what would be the proper braking technique?
I've never tracked a car before, but I imagine the proper technique would be to get on the brakes hard, but for a short time, instead of riding the pedal into the corner.
So, get on them smooth but hard, then off again and let them cool till the next corner...
Can someone elaborate?

[pixelblue]

^ you are correct! This technique is called threshold braking. Slippage generates heat so the harder you brake the less slippage is created. Racing brake pads actually generate less heat because of the higher torque generated by the more aggressive compound.

[mojo1]

http://www.1addicts.com/forums/showt...=brake+cooling

[mbintx]

So, that track day was today. Overall impression: car has very nice power on the straights. Cornering was so-so. Still more push that I would have liked, but it wasn't horrible. I think camber plates up front would definitely help.
Brakes-- honestly, pretty disappointing. Spent most of the day instructing and only ran two sessions in my car. Morning session was cold and grip was nowhere to be found. I got about 3 or 4 laps in at 7/10ths before the pedal got long and my confidence got short.
Afternoon session was warmer and track has some rubber on it. Pushed the 135i a bit harder, and had two decent laps at 8/10ths before pedal got very mushy and ABS kicked in in quite a few braking zones. After that, had to back off and let brakes cool off before trusting them again. Bottom line: brakes are definitely the weak point for any track exercise. Better fluid is a must, and better pads are highly recommended. Lesson learned. Now back to the Miata for track fun!!!

[TX78666]

mbintx, I'm a little late to the thread, but your PM got me curious about your background. If you are an instructor, then 7/10 or 8/10 for you is likely well beyond 10/10 for novice/intermediate drivers - i.e. most owners and most people on here (this site in general, not this thread), wondering if they can take their car to the track.

Having ridden with some instructors, I'd wager that most of us are at 7/10 or 8/10, where instructors are at 4/10 or 5/10. At that level (IMO) there is nothing particularly limiting about the brakes, the runflats, the suspension, the open diff, or pretty much anything else, other than the driver.

Just my opinion, and I know most drivers probably don't like to hear it. I know I don't, but I've lived it, and while I put myself in the same novice/intermediate group, I'm generally faster than all of the green drivers and half of the blue. I'm not out for a Sunday drive, and I have never had problems with the brakes. I suspect that anyone who has never been to the track before, provided they are going with a good organization, like Driver's Edge, will have the same experience.

[TX78666]

For people who do this sort of thing quite a bit, I suspect you are correct on all points.

[TX78666]

Sorry for the completely WTF post, relative to the discussion in this thread. I came by the thread through an unusual path, and didn't read all of the posts, until after I posted my reply.

Stupid, but it's been one of those days. I stand by what I said, though. I feel bad when people who have never been to the track get scared off and/or start emptying out the kids' college fund, to upgrade everything on their cars, based on what some advanced drivers, waaaaaaaaaaaaaaay beyond their ability levels, are doing.

[mbintx]

TX78666,

Point(s) well taken. While I am certainly not a professional race car driver, I do have enough experience on tracks to probably be quicker than most people who run occasional HPDE days. And I have enough track time to be called on to instruct at times when help is needed. So yes, when I mention 7/10ths or 8/10ths, the frame of reference is MY skill in MY car. My 7/10ths might be quicker than someone else's 9/10ths, but might also be slower than some hot shoe's 6/10ths.

My direct comparison was also to my track-prepped Miata, which isn't fair for a stock 135i, like it or not.

So for someone who is doing their first or second HPDE, or is by nature a careful and non-aggressive driver, a stock 135i will do just fine. But once track time, skill, and pace pick up, the shortcomings become more noticeable.

[DriveHard]

i know this is an old thread , but i promissed to update ..

i started a new thread here : http://www.1addicts.com/forums/showthread.php?t=663510