what is this crap on my rotors?

[mole]

got a 95 325i. when i saw my car this morning, it has all this yellow/orange crap on each rotor...
it seemed to of just happened overnight w/o me even driving it.

pics...

[mole]

two.

[mole]

three.

[CiscoKid]

that would be rust... its normal

[mole]

from overnight? :|
so can i just scratch it off?

[dport]

As soon as you pull out of your driveway it will gone. Completely normal.

[mole]

year, your right. it's all off now.

i freak everytime i see something odd about my car.

[leibniz]

It does seem odd for that to occur overnight.

If I leave my car for about 2 weeks without driving, I get rust forming on the rotors. But NEVER over a single night.

Mind you, I suppose location has a huge part in all of this. i.e. humidity, air temp, overnight temp, etc. etc.

It's fairly dry where I live.

[El Presidente]

I had noted rust on my rotors when I left work about an hour ago.

We had some wicked storms though; our building even started to flood.

[BlantonG13]

that usually happens on anyones rotors when it rains. It can even happen if dew settles overnight, perhaps with a vast change of temperatures-same kind of thing when you see dew/water on your windshield when you wake up for school or work in the morning. A lot of it could even be just rusting of settled brake dust. All very normal.

[Torque]

it is a very tiny layer of rust. as soon as you apply the brakes it rubs off.

completely normal on all cars.

[dutchbmw]

Hey mole, that are not the original rotors! Maybe that's why they rust in one single night!!?

[wulley1]

rain will do it over night, but High Humidity for more than 6 hours will do it too. If the relative humidity is inthe 70% or higher, you will probably see it 10 to 12 hours latter, especially if there was already a little bit of rust present.

[RIBEMR26]

It's called "flash rust" and will happen on all rotors even from just washing your car.

[thinair]

Originally posted by RIBEMR26@Jun 21 2004, 05:19 PM
It's called "flash rust" and will happen on all rotors even from just washing your car.

This is true, I get rust on my rotors about half an hour after washing my car, a nice thin coat of orange.