Brake Dust on One Wheel?

[Evoking]

I've been noticing that the right front wheel gets way more brake dust than the other one. Like a day after a wash it is dirty while the left is still fine...

Anybody else seen this with their M Coupe/Roadster? It has 25k so I doubt the pads are done but I assume this is something that BMW would cover under maintenance anyhow.

[thekurgan]

Seems unusual unless you have one of the intake vents blocked somehow or you have a sticking caliper.

[scottyD]

I learned this trick from my father...

After driving awhile at decent speed, stop carefully without using much of the brakes, and then get out and compare temperatures of the rotors on the different sides. You can do this either by using the back of your hand to sense how much heat is radiating from the rotors (don't touch, just in case), or by spitting on the rotor surface and noticing the reaction.

Cool rotors, which you should have after driving for awhile and not using much of the brake pedal, won't feel warm and if you spit on them it won't do much of anything.

Hot rotors, which might indicate a seized caliper, will just feel hot (without touching) and if you spit on them, it should instantly sizzle.

If the right side is very hot while the left side is cool, I'd say to replace the right caliper. You're lucky if you can have it replaced under warranty.


My wife's Jetta had seized calipers on both sides in the rear at 250 miles on the odometer. After driving it home from the dealership I could just smell something was off and sure enough the rear rotors were both sizzling hot.

[epbrown]

I haven't driven my M Coupe in about a month, but the thaw we got this week in Chicago let me take her out this week. On a brief run to a restaurant, I had these exact symptoms with the driver's side front wheel - the rotor was glowing and pinging it was so hot! I did a search on caliper and came across this thread, and took it in. The dealer replaced the caliper, brake pads, and rotor under warranty. I'm guessing the inactivity caused the rotor to seize - they said the piston wouldn't free for anything. Thanks for the description, SD.

Originally Posted by scottyD

After driving awhile at decent speed, stop carefully without using much of the brakes, and then get out and compare temperatures of the rotors on the different sides. You can do this either by using the back of your hand to sense how much heat is radiating from the rotors (don't touch, just in case), or by spitting on the rotor surface and noticing the reaction.

Cool rotors, which you should have after driving for awhile and not using much of the brake pedal, won't feel warm and if you spit on them it won't do much of anything.

Hot rotors, which might indicate a seized caliper, will just feel hot (without touching) and if you spit on them, it should instantly sizzle.

If the right side is very hot while the left side is cool, I'd say to replace the right caliper. You're lucky if you can have it replaced under warranty.

[thekurgan]

Originally Posted by epbrown

I haven't driven my M Coupe in about a month, but the thaw we got this week in Chicago let me take her out this week. On a brief run to a restaurant, I had these exact symptoms with the driver's side front wheel - the rotor was glowing and pinging it was so hot! I did a search on caliper and came across this thread, and took it in. The dealer replaced the caliper, brake pads, and rotor under warranty. I'm guessing the inactivity caused the rotor to seize - they said the piston wouldn't free for anything. Thanks for the description, SD.

How often have you changed your brake fluid?

[epbrown]

Originally Posted by thekurgan

How often have you changed your brake fluid?

Only once, this past Spring. I've only done 18k miles, but went by the 2-year interval.

And btw, got it back today. Someday someone will have to explain what's so difficult to understand about the phrase DO NOT WASH.

[thekurgan]

I dunno, some dealerships just ignore but if you leave a note on the seats or the dash, that can help. I would go by the 1 year interval or less if you can on the brake fluid, but it sounds like a defective caliper if the other 3 were ok.

[BTM]

Originally Posted by epbrown

Only once, this past Spring. I've only done 18k miles, but went by the 2-year interval.

And btw, got it back today. Someday someone will have to explain what's so difficult to understand about the phrase DO NOT WASH.

Glad it's back on the road...I hear ya about dealer washes...actually got mine hand washed this morning...not sure who you use for detailing but if you want I'll PM you the info for the guy I use

[epbrown]

Originally Posted by thekurgan

I dunno, some dealerships just ignore but if you leave a note on the seats or the dash, that can help.

This is a transcript of my pick up:

Me: I'm here to pick up my car.
Receptionist: Okay. I noticed it's kinda dusty, would you like us to wash it?
Me: NO. Thank you.
Re.: It's really dusty. Are you sure?
Me: Positive. No thanks.
Re.: Okay, it will be right down.
Me:.....
Porter: Here you go, sir. Sorry it took so long, we washed it for you
Me:
Porter and Receptionist:

[thekurgan]

Originally Posted by epbrown

This is a transcript of my pick up:

Me: I'm here to pick up my car.
Receptionist: Okay. I noticed it's kinda dusty, would you like us to wash it?
Me: NO. Thank you.
Re.: It's really dusty. Are you sure?
Me: Positive. No thanks.
Re.: Okay, it will be right down.
Me:.....
Porter: Here you go, sir. Sorry it took so long, we washed it for you
Me:
Porter and Receptionist:

The receptionist noticed?

[epbrown]

Originally Posted by thekurgan

The receptionist noticed?

What was even more odd is she knew it was an M Coupe. In 3 years I've never had one of them know what - they always look at the invoice and ask "This just says M Coupe - is it an M3 or M6?"

[thekurgan]

Originally Posted by epbrown

What was even more odd is she knew it was an M Coupe. In 3 years I've never had one of them know what - they always look at the invoice and ask "This just says M Coupe - is it an M3 or M6?"

The rarity of the car does have some challenges. I recently got some new blade inserts, mentioned they were for an M coupe, but they gave me E92M3 inserts ... seems like your receptionist knew more than my BMW parts guy.