Brake Pad Wear Sensor Tripped

[mikeinsf]

Any pointers on the following?
1) the cheapest place to source new rotors
2) ceramic pad choices (I'm so over brake dust)

I haven't had chance to take off the wheels yet to see whether it's the front or rear that's tripping the light. I'm guessing it's the front though.

Also, what is it about our rotors that they can't just be turned like every other car I've had? Just a question. If new rotors are just what's necessary then so be it.

[gatorfast]

I believe the sensor monitors the front pads only but could be wrong.

[Pheonix]

No, i think our cars have both front and rear. It is a good idea to replace the pads before the sensors wear out cause that would run you some $20s each.

[mfanatic325]

There's one sensor up front and one out back, on opposing sides. I believe it's front driver side and rear passenger side. Cheapest place for rotors is still Tischer BMW, so try them out Mike. I currently have a brand new set of fronts waiting to go on my car, and I technically can wait since I don't plan on any track days in the near future; but I don't see any reason to let them go unless it's for a slight profit lol. But don't worry, I'm not one to rip people off

In any case, I don't have any recommendations for you as far as dustless pads go. I've only personally used OE pad material thus far, and still have two more full sets waiting to get romped on at the track lol. I should be able to go through a full set @ Laguna Seca within two days. Good thing the rotors last much longer xD

I used to hear long ago that ANY cross-drilled rotor cannot be turned/refinished, but I've also heard that it can indeed be done. I've never personally had it done, but I'd say that unless you're tracking the car a lot and really looking for maximum braking capability, it's okay to just slap on some new pads and just bed them nicely (provided of course that your rotors are still within spec thickness overall).

[Finnegan]

I'd measure the rotors before replacing them, just as Mfanatic suggested. They are not cheap, and fronts go before rear.

Per Shipkiller's post the min front thickness is 26.4mm (fronts). Not sure about the rear, but it's stamped on the rotors, all you need is a caliper to measure them in several places across and around the rotor.

Mfanatic is correct about the location of the wear sensors. They are cheap to replace.

Lots of folks like the Akebono ceramic pads--quite a few threads here on the topic of dust and pedal feel and so on to look at.

[santov]

I have a strong opinion on rotors and pads...

I have a 3.0si that I never track and only use as a daily driver. The stock rotors are solid, and after prior experiences I didn't' want to spend the extra money on slotted and/or drilled.

I'm also a HUGE fan of CENTRIC products. I've used their rotors and pads on just about every family and extended family brake job I've done. The finish of their rotors is top notch. When it was time to do my brakes I went with Centric pads and rotors. They were the budget line and holy crap they've performed well! And the brake dust is almost nill.

Write up here: http://www.zpost.com/forums/showthread.php?t=617335

But if I were you and I had a Z4M I'd go with new rotors for sure. Most places wont resurface drilled rotors and even then it would probably result in a horrible finish. For pads I'd go with cool carbons. They had great reviews on BavAuto.

[beta]

Originally Posted by Finnegan

Lots of folks like the Akebono ceramic pads--quite a few threads here on the topic of dust and pedal feel and so on to look at.

+1 for Akebono. No issues with performance, no noise, almost no dust (and when it dusts it's fine and light, so you can't even tell). Couldn't be happier.

[mfanatic325]

Didn't Brembo or StopTech buy out Centric? Or vise versa, I forget. In any case, Centric was already a pretty good brand to begin with. Then after the merger, they carried over many fresh and new tech

For me though, I'd just stick with OE rotors on the Z4M. They're not all that cheap, but they last satisfyingly long

[gatorfast]

How long are you guys seeing your rotors last before needing to be replaced? I know this will depend heavily on whether the car is tracked or not. Im at 46k miles and as far as I know Im still going on the original set (bout the car about a year and a half ago with 26k miles. No tracking, just daily driver for me.

[mfanatic325]

I've heard 60k miles for regular street usE =O !

Mine's been beat at the track and the rears got replaced first under warranty (I think the stealershit just wanted to save some money by not giving me front rotors as well -_-) @ almost 30k miles. So it's safe to say that street use rotors will probably last twice as long as tracked rotors, if not more.

[mhughett]

Originally Posted by mfanatic325

Didn't Brembo or StopTech buy out Centric? Or vise versa, I forget. In any case, Centric was already a pretty good brand to begin with. Then after the merger, they carried over many fresh and new tech

For me though, I'd just stick with OE rotors on the Z4M. They're not all that cheap, but they last satisfyingly long

I had problems with the OEM rotors and pads on my M coupe. The rotors were pulsating within about 3 months every time I got a new set (under warranty). After about 3 replacements and the same outcome, my warranty ran out, the dealer said no more replacements so I bought some Racingbrake rotors with StopTech street performance pads. So far (two months), they have been great. No noise, straight and true braking and very little dust. One of the pleasant surprises is that the stoptech pads don't seem to be as grabby when you first touch the brake. The Racingbrake rotors are about 50% more than the OEM's but they are still less than the StopTech BBK by a long ways. So far this combination looks great.

[mfanatic325]

Your case was definitely extremely rare and odd. Not sure what was wrong with all of your sets of rotors and pads. Or perhaps somehow car or tire related?

[Hawkeye]

I am at 57K miles and am on my original pads and rotors. I will be getting ceramic for sure when I need to replace, probably next season. I have been very happy with the stock equipment's performance thus far though.

[rsutoratosu]

Originally Posted by santov

I'm also a HUGE fan of CENTRIC products.

Which centric do you use ? those OE type cross or the high carbon rotor.. Do you have a part # ?

[oj]

I currently have the akebono ceramics. And while it is nice that they don't give off any dust, I plan to go back to the stockers. They stop the car OK & I am sure that I broke them in properly. I prefer the bite of the normal pads.

I too am curious which Centric rotors people use. Centric makes about 8 different rotors and I am not sure which one is compatible with CSL brakes.

[MinneapolisJeff]

so generally everyone replaces the rotors along with the pads? i'm close to tripping the sensor (in fact I had expected to see it at the end of the 2011 driving season) and simply wanted to swap in Akebono pads

[mhughett]

Originally Posted by oj

I currently have the akebono ceramics. And while it is nice that they don't give off any dust, I plan to go back to the stockers. They stop the car OK & I am sure that I broke them in properly. I prefer the bite of the normal pads.

I too am curious which Centric rotors people use. Centric makes about 8 different rotors and I am not sure which one is compatible with CSL brakes.

When I went looking at alternatives to the OEM rotors for my coupe, I checked with Tire-Rack on their Centric rotors. The one they had is NOT like the picture. It sounded like it was a drilled rotor like the OEM as opposed to a solid rotor like the picture. I found there are very few alternatives to the OEM CSL rotor without upgrading to a BBK like Stop-Tech or Brembo. I ended up with RacingBrake because their slotted 2 piece rotor was the exact size as the OEM so no other hardware was required.

If you were interested in a cheaper alternative, I later found out that the OEM size for the 335i rotors was the same diameter and only about 2mm thicker than stock rotor for the M's, which will likely work with most pads. You can get solid rotors for this size for <$100 each but they will be slightly heavier than the OEM rotors.

[SONAR]

Originally Posted by Pheonix

No, i think our cars have both front and rear. It is a good idea to replace the pads before the sensors wear out cause that would run you some $20s each.

Yup, there is one sensor on the left front and another on the right rear. If sensors are tripped they need to be replaced or bypassed

[MinneapolisJeff]

Originally Posted by SONAR

Yup, there is one sensor on the left front and another on the right rear. If sensors are tripped they need to be replaced or bypassed

so how/why does the sensor get ruined when it is tripped? how is it saved when you change the pad before it's tripped?

[SONAR]

It's a metal probe that's covered with a plasticized or rubber type coating. It starts to rub this coating away as the pads get low, and eventually when the metal is exposed, completes the circuit illuminating the brake light (or whatever it is, never had it go off). So if you install the worn sensor, there is no rubber to insulate, and it will think you need pads again.

[Finnegan]

The sensor basically snaps in and out of a notch in the pad itself. Once the pad gets to a certain thinness the rotor comes into contact with the sensor, doing what Sonar describes above. Swapping out for new pads before this happens 'saves' the sensor.

[MinneapolisJeff]

Ahhh understood. Always wondered how those sensors worked. I think I have myself a nice little project to complete before the 2012 driving season starts.

Wonder how much my local stealership charges for those sensors...