Whats this on my brakes!?

[Arnold]

Noticed this on my brake discs the other day and was just wondering what it is?

 

[Grant]

looks like rust???

but its a bit too yellow.

 

[Arnold]

Its not rust as when i turned the wheel, the brake pad scooped it all off

 

[Grant]

could be something you drove throught

reacting with brake dust or something like that.

 

[Arnold]

Possible, it wasnt there when i left her and came back 4/5 hours later and saw it (it appeared when it was parked!)

 

[Grant]

as long as theres no damage mate i wouldnd worry.

 

[goldstar0011]

Thats normal, last time i checked it, I get it after rain or damp nights

 

[Arnold]

Well no physical damage but they're kind of important part of my car! Il be fitting vented brakes shortly anyway if its a fault of the disk, but just curious to know what it could be.

 

[BenK11]

It's surface rust (Y)

 

[Ed]

Thats right this is rust. Its common, it can happen within an hour after you even wash a car, but as soon as you drive off, it will go.

 

[Arnold]

ahh ok! didnt think rust could form so quickly.

cheers people

 

[Craig]

The heat of the disk will acceleratethe oxidisation of the ferrous elemnts in the disk/traces of pad left on it

 

[Ed]

He heat also evaporates any moisture on the disk preventing rust lol..

 

[goldstar0011]

Chemistry 101

 

[Ed]

I once tried to make iron fakes to make a kind of gunpowder that sparkled like sparklers do, so I got some iron and as anyone will know after you have cut the metal you are left with a pile of iron filings - perfect I thought, so I tried an angle grinder and this didn't work. Afterwards it hit me that holdon as you cut the metal, it spakes so its already oxidised and its hardly going to want to burn again... LOL.. Hmm well I was young then haha.

 

[Craig]

Lol to ^^

There is also moisture in the air though

 

[janjachnik]

Yea i have the same problem. Mine are always rusty. When i take my car out the first time i use the brakes there is a scraping as the rust comes off.

 

[simmo]

first couple of times u use the brakes after they have rusted abit they r really good cuz of the extra friction! soon cleans off thou...