Hello Guys,

I'm changing my front brakes as there is around 2mm left of brake pads. Oddly, this time the front brake sensor didn't light up like last time. I was told that for all new BMW, Mercedes, and Nissans too that you are suppose to change the rotors at every second brake change. Sometimes, I only think that is a way for the dealership to make money. Since you have the brake pads off, why not change the rotor and charge the customer the labour time and make the parts money. My ML320 has the following thickness..

Front Rotors: 24mm
Rear Rotors: 15mm

Do you guys suggest changing the rotors as if what I said above is true, its time to change them. I noticed scoring on the rotors near the center on both sides. Anyone know the min. thickness specs?

Tabo

Min. rotor thickness should be stamped on the "hat" of each rotor. You have not said if the rotors on there are original or had been replaced with aftermarket, so I cannot say what the Min. thickness is. Rotors every other pad change is generally true, especially up front. Rears may go every thrid pad change, depending on the loading of the vehicle. This is assuming standard semi-metalic pads.

If you want them (rotors) to last longer, go with basic ceramic pads (like the ones from Satisfied). Same stopping distance and power, but quiter, much easier on rotors, and best of all, leave your wheels cleaner than you can imagine.

Minimum thickness for rotors on a ML320 are as follows; front 23.0mm and rear 13.0mm. This is for a stock rotor. Check to make sure your rotors are oem and not aftermarket. It's your call whether or not to replace the rotors at your 2nd brake change, but truefully most ML models don't make it to the second brake pad change before the rotors are below min specification. Actually I see quite often that when the pad light comes on for the front pads that the rotors are only about .5mm above min specification and I usually suggest replacement at that time. Whether or not I suggest replacement usually depends on when the next state inspection is due. It doesn't make any sense to just replace the pads if your state inspection is coming up and your rotors are getting close to min. spec. I've also seen some of these mercedes models have the rotors wear out before the pads do. Hope this helps
Dustin

What is the minimal thicknes of ML320 front brake pads? And how do I measure it correctly? Thanks!

__________________
1999 ML320
100,000 miles
77K - engine failure


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There's zero/zip/nada reason to think the minimum thickness specification isn't the same for OE and aftermarket rotors. It has as much to do with maximum extension of caliper pistons as anything.

It's a silly question to ask if it's needed every time, every other time, or whatever. It's needed when the rotors are at or below minimum thickness. Consideration should also to be given as to whether they will wear past minimum thickness during the lifetime of the new pads about to be installed.

Skimping on any maintenance is foolish and skimping on brake maintenance about the dumbest of all.

To expect a professional service facility to play games with your safety--even if you requrest it--is to miss the point.

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Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

to know the minimum thickness of the rotor: it is stamped on the inside of the rotor. Just remove them and have a look.