brakes and rotors
Thread Starter
Newbie
Joined: Jan 2014
Posts: 8
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CLK350
brakes and rotors
Hi ya'll
My break pad wear warning just came on. I went to the shop and they said I need rotors as well. Just to validate this myself, I have read about some sort of nail test for the wear of the rotors. I can tell there is a lip and the difference from the rear but I don't think it is thicker than a CD. How do you guys judge when the rotors need replacing? How do you do the nail test? How long do you have once this warning comes on to fix?
Thanks for the help!!
My break pad wear warning just came on. I went to the shop and they said I need rotors as well. Just to validate this myself, I have read about some sort of nail test for the wear of the rotors. I can tell there is a lip and the difference from the rear but I don't think it is thicker than a CD. How do you guys judge when the rotors need replacing? How do you do the nail test? How long do you have once this warning comes on to fix?
Thanks for the help!!
MBWorld Fanatic!
Joined: Apr 2005
Posts: 3,784
Likes: 84
From: SCV SoCal
2002 CLK430
You know the rotors are out of spec by using a tool called a micrometer to measure their thickness. When they're too thin, they're replaced. On my car, that's every other set of pads. The wear limits are usually on the rotor hub. If not, I have them at my website.
One last thing, like Porsches, you don't turn the rotors.
One last thing, like Porsches, you don't turn the rotors.
MBWorld Fanatic!
Joined: Mar 2008
Posts: 1,232
Likes: 168
From: Glasgow, Scotland, UK
SL 350 R230 (3.7L with AMG Speedshift autobox)
You can tell clearly if the rotors are worn by the lip that usualy forms and dictates the amount of material that has worn down, a slight lip of a few mm is totally normal but if dirt gets stuck on the pad it can leave heavy scoring on the main disc like a record. However rotors are pretty cheap its a good idea to just replace them with the pads, I've found that my front pads last for 5+ years so its not a frequent expense.
