Is this something I should get checked??

I just finished washing my car and was backing it down our very steep driveway - braking at the same time when this very LOUD, deep growl (best way to describe it) resonated thru the cabin of the car at the same time that I had to apply much more force to the brake pedal than I normally would need to stop the car rolling.

This is the second time I've heard this sound. Circumstances were identical the first time. I always get my brake rotors and calipers nice and wet when I wash my car as I wash the rims and bright yellow painted calipers (as best I can thru the spokes). Anyway - this time round it worried me a bit so I backed right out the driveway and went for a fang round the neighbourhood doing the "bedding in" proceedure around 8 times. I braked fairly moderately the first time - and after that the brakes felt like normal. Presumably this is directly related to excess water on the rotors and pads while they're cold.

I was just wondering if anyone can explain exactly why it makes such a awefully loud sound (the missus heard it loud and clear from inside - at the other end of the house!!!) - and is it something I should get checked??

Original brake rotors and pads were replaced < 15,000km ago with DBC slotted/X drilled and Bendix Advance pads. Brakes behave themselves perfectly except for these two occasions - and I never wet the wheels (washing the car) immediately after driving.

Thoughts??

this happens to me too. when the rotors have dried after being wet, a film of red dust appears on them. (i assume it's surface rust??? ) it's this that makes the noise - just needs to be driven a bit to scrape the excess dust of the rotors.
i don't think this is bad thing for the rotors (they need to be hosed out anyway), just annoying.

Has it only happened when reversing? Could be a combination of water, cross drilling and slow speed causing vibration through the calliper/brake pads. I've had a similar effect in other cars but not as severe as yours sounds.



.

your situation is weird but if it's just a "croaking" kind of sound, it's perfectly normal. the sound goes away after awhile too. the reason is because there is a thin film of brake compound, dust and oil film. when you wash your car, that film gets washed away. this is also why you feel your brakes are a little more responsive after each wash. but they return to normal feel after awhile. it's analogous to washing a dish... it feels and sounds squeeky clean after each wash.

Yeh it's normal my car does the exact same thing, thunders through the cabin, scared the crap outer me at first.

If you wash your car straight after driving, and you spray the hose directly onto the brakes, the instant cooling will cause the rotors to warp. Therefore when braking, or sometimes even without the brakes applied you will get a grinding noise.

If you wash your car straight after driving, and you spray the hose directly onto the brakes, the instant cooling will cause the rotors to warp. Therefore when braking, or sometimes even without the brakes applied you will get a grinding noise.

No sh!t. Read my post;

and I never wet the wheels (washing the car) immediately after driving.

Thanks everyone else, good to know I'm not the only one. You've helped confirm my theory that it has to do with the water / washing - just never noticed it till we moved into this house with the cr@p driveway!!