EROD

How do you check/measure brakepad wear? Or do you just wait until the light comes on? I had my front pads replaced by the dealer at around 25K miles due to what they called "abnormal" screeching noise but the rears are still the orginal ones with 36K mile of normal drving on them and wondering if they need replacement anytime soon.

Do the sensors need to be replaced if you replace the brake pads before contact is made between the rotor and sensor?

drjazzsk

I was actually wondering the same thing. I was told my brakes were "low" by the stealership but have seen no change in performance, no weird noises and no sensors tripped. Hopefully someone can shed some light on this.

CarHopper

Just take a look at the pads. I mean you can really only see the outside pads but its a decent way to judge. Then, just make a judgement call. See a decent amount of pad left then you're good to go. I'd say 1/8th'' or less and you'd want to think about replacing them.

intence

i just bought my c63 too and the ppi reported it needs new pads. im assuming the dash will notify me when its low? i do hear some slight squealing though

BerBer63

Sensors are set at about 2mm of brake pad. I changed mine before it hit and re-used the sensors.

Skydiver13

My brake wear message just started coming up, so I'm taking it in to be assessed. Dealer told me that even if it has 25% of its pads, that I could still go another 10K miles, but I'll probably get pads replaced and be done with it.

CarHopper

Squealing could also come from brake dust. I'd check the wear on the pads themselves.

Yea that's what I figured. That 1/8th inch is a hair over 3mm so that's right about when I'd get ready to replace pads.

EROD

Could the amount of pad material left be measured by sticking a feeler gauge between the rotor and the pad "frame"? How/what does the dealer measure to be able to tell you have xx% of pad left?

BerBer63

you can see it through your spokes

CarHopper

Not entirely sure what the dealer uses to measure a % of pad... I feel like it is mostly an eyeball type thing where they just judge a new pad vs the ones on the car and say "eh, looks like 25% pad life left..." Could be wrong and maybe there is a science to it but I doubt every tech at every dealership gets an exactly measurement.

If you're really curious just walk around your house and find some items that you feel range from something like 2mm thick to 5mm thick. Then, just start matching them up to the pad and you can get the thickness that way. That's what I'd do anyway if I was really curious as to how much pad was physically left.

Then, if you wanted to take it a step further, figure out how thick an OEM pad is. Lets just say, for example, its 10mm thick and you have ~2.5mm left therefore you're at 25%.

Regardless, anything less than 3mm and I'd change the pads when I had the chance and definitely if the warning came on.

JCH

I replaced the rear pads at 40k miles (rotors were fine) and just replaced the front pads and rotors at 60k miles. Tech said the rears wear out first on the C63.

m a x i m u s

you can use a 2mm (or whatever size) allen key and stick it in there to measure the thickness.

Merc63

That's because you drive everywhere with ESP on.... Every time you stomp on it the ECU hits the rear brakes to stop it from spinning.

I drive with ESP off and my fronts and rears were equally wore out.

motoman

At second brake fluid drain some measurements 09 P1...23K miles, daily driver no hard driving. Live at 2000 ft (so hilly).

Rear rotors : RR 1.030" (.096 left) LR 1.025" (.029 left)

Front rotors: RF 1.42" (.100 left) LF 1.380" (.060 left)

Pads hard to measure. Used back side of a caliper (pointed ears). Measure metal backing plate to disc and subtract metal backing plate thickness) Backs about .25" ( .6" new?) Fronts a little thicker.