y2b4sure

Hi. My front pads are getting low, 60k on my R500. I wasn't sure if I needed new rotors, so I took the front left wheel off looking for a stamp showing the minimum thickness, but found nothing.

The rotor thickness is currently 1.185 inch / 30 mm, does anyone know what the minimum thickness is?

Thanks.

avlis

I always replace the rotors when I replace pads and I think MB does too. Therefore, they probably don't bother to stamp minimum thicknesses of their rotors.

lkchris

There are two minimum thickness numbers.

1. don't use below this thickness

2. don't replace pads below this thickness without also replacing rotors ... since the rotor won't last the life of the new pads.

Obviously the 2nd number is more relevant and I don't have a W251 DVD but for the W164 which I'm sure are similar the difference between new and the replacement wear limit is 2mm. You can estimate your missing metal by observing the "lip" on the outside edge of the rotor. (remember it's 1mm per side) Front brakes on an ML350 start at 32mm and the limit for pad replacement is 30mm. The final limit is 29.4mm.