Red97LT1

Ever since I put new rotors on,there have been brown rust looking stuff that gets on them.Is it rust?How can I get rid of it?? Brakes perform fine,it just looks bad.Thanks

bmillington

Does it come off after a little driving/braking?

Red97LT1

Yep.

bmillington

I'm not expert, but I've seen rotors get rusty pretty quick before. Normaly it takes a couple days without driving though. Could be the type a steel the rotors are made of or the matalic compoents in the brake pads. Do you live close to the beach.

Red97LT1

Nope. Not near the beach.More near the mountains. It gets all over them.Comes off when i drive,because the pads cleans them off,then it comes back.

Injuneer

The rotors are cast iron. Bare cast iron, exposed to air rusts. Add a little moisture - rain or even high humidity - and they rust faster. Completely normal.

Red97LT1

The previous ones never did what these are doing.

n2ceptor

Probably a different treated iron..... I wouldnt worry about it....

Red97LT1

It just looks bad.

godofdragons

dont worry dude, mine do the same thing whenever it rains. you dont store it for long periods of time do you?

LPEdave

If it really bothers you, you could get zinc or other coated rotors. Of course you just got new rotors, so that's probably not what you had in mind...

Dave

Injuneer

The purity of the iron is going to have an affect on how fast it rusts. I remember working on a process to concentrate iron ore to high purity iron in a fluid bed reactor, and then briquetting the resulting powdered iron so it could be used in blast furnaces in place of "scrap iron". The first pile of iron briquettes caught on fire, because the very high purity allowed the briquettes to oxidize rapidly, which is an exothermic reaction. The resulting heat was enough to light the pile of briquettes on fire, fueled in part from some residual hydrogen trapped in the briquettes during the manufacturing process. Ultimately, the briquettes could only be shipped in sealed drums with nitrogen blanket. Pure iron rusts very fast.

The zinc-wash won't really help a lot. It only protects the part of the rotor that isn't swept by the brake pads. I have the Baer zinc-washed rotors, and with the car having sat unused in the garage for many months, the swept area of the rotors has a thin coating of fine rust particle. Storage can accelerate the process, as the metal heats and cools from ambient temperature changes, causing moist air to condense on the rotors still cold from an overnight temperature drop.

This picture wasn't taken to show the rotor, but you can see the light coating of rust, even though it is "zinc-washed".

http://cjcfo.fbody.com/members/injun.../DCP03544a.jpg

LPEdave

Interesting stuff, Fred.

Here's a pic pof my reasonably well-used zinc washed rotor, and my car sat for significant periods of time, causing causing plain iron rotors to get nice and rusty. I was always happy with the zinc coating - while a touch of rust did show, it was nothing like when they were raw. I suppose where you live, and the humidity in the air, would have a significant impact. http://www.go-fast.org/z28/MyParts/brake4.jpg

Dave

Red97LT1

My car is a daily driver,so it doesn't sit more that probably 5 hrs at a time. I got the rotors from autozone and the guy down there couldn't begin to explain what was going on with them. He then goes into a speech about how his wifes factory rotors do the same thing. WHO CARES! is what i told him. I 'm not here about your wifes rotors,I'm here about mine.I considered the zinc plated ones,but was told that the zinc would just wear off as time goes by? I'm just glad that the winter time is coming,so the rotors won't be that noticeable since it will start getting dark at 5pm now. Think i'll just grin and bear it until next summer when i get new rims,then try to get something that doesn't rust as bad.