2013 ML550 brakes
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2013 ML550 US spec. Air+Offroad pkg
2013 ML550 brakes
My 2013 ML550 with 60k miles is on its 3rd set of rear brakes, but original fronts with nearly all of pad material left. Car does not have active lane keeping assist or active distronic (which use rear brakes). This seems very odd to me that fronts don't wear but rears wear out every 20k miles. Dealer said they see MLs going thru rears quicker than fronts because they think MB engineers rear brakes to catch first to soften the braking experience, and prevent nose dive.
(Brake fluid is routinely flushed, rear rotors replaced once and resurfaced once...3rd set of pads)
Is this normal on W166? Have you experienced the same? Is there something we should look at that may be causing this?
(Brake fluid is routinely flushed, rear rotors replaced once and resurfaced once...3rd set of pads)
Is this normal on W166? Have you experienced the same? Is there something we should look at that may be causing this?
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2017 GLE350 4MATIC
Normal.
Regular non-Distronic cruise control uses rear brakes, as does HOLD function. As does the rear electric parking brake. It all adds up over time.
Additionally, the rear brake pads are smaller in surface area and thinner in depth vs the fronts. This means there is less cubic volume of pad material on the rears. What is unknown is whether or not the rear pads are softer/faster wearing chemical composition vs the fronts.
In summary, MB has made a system of vehicle level engineering choices that result in faster rear brake pad wear vs the fronts.
Regular non-Distronic cruise control uses rear brakes, as does HOLD function. As does the rear electric parking brake. It all adds up over time.
Additionally, the rear brake pads are smaller in surface area and thinner in depth vs the fronts. This means there is less cubic volume of pad material on the rears. What is unknown is whether or not the rear pads are softer/faster wearing chemical composition vs the fronts.
In summary, MB has made a system of vehicle level engineering choices that result in faster rear brake pad wear vs the fronts.
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2014 ML350 4Matic
Chassis said above: "In summary, MB has made a system of vehicle level engineering choices that result in faster rear brake pad wear vs the fronts."
Exactly. The front brakes have much bigger double-disc rotors. By comparison, the smaller single-disc rear rotors are puny. The 20K life-span sounds short though - I get about 40K out of mine - but its always the rears that go first.
Exactly. The front brakes have much bigger double-disc rotors. By comparison, the smaller single-disc rear rotors are puny. The 20K life-span sounds short though - I get about 40K out of mine - but its always the rears that go first.
Last edited by sams_6; Feb 6, 2022 at 01:28 PM.
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ML400s, GLE400s and GLE/ML350s with P31 all ( I refer to US cars only) are equipped with 350x32 (13.8" diameter) front 322x22 (13") rear rotors, both are vented.
Now the OP's '13 ML550 (as all W166 ML550s and GLE43s) is equipped (by comparison to the above) with truly massive front 375x36 (14.8") vented rotors. OP's rear should be 330x22 (13" diameter) vented AND drilled rear rotors (it was even stated somewhere that some 2012-13 ML550s and ML350s with "AMG" P31 package were equipped with 345x22 (13.6") drilled rear rotors, instead of 13"). (From 2014 MY on, MB dropped cross drilled vented 13" rotors and used solid vented 13" rotors instead). The difference of front to rear rotors and pads is significant and it make sense why rear pads wear significantly faster if electronic gadgets (DAP and Active Lane assist) are used. Same applies to ML/GLE63s.
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2017 GLE350 4MATIC
Folks, it's an energy thing. And we are talking about pads here, not rotors.
@threeMBs compare AMG front pads and rear pads in the same photo. Note the area difference front and rear. Note the thickness difference front and rear. We are talking about pads here.
Rotor design is anecdotal for this conversation. A wider (thicker) rotor tells you it has been designed to absorb more energy than a thinner rotor. Best measurement of all is rotor weight. It's an energy thing.
The quantity (cubic volume) of pad material equals the amount of energy that will be converted from kinetic to heat as the vehicle is decelerated. Pads die and go to Heaven when performing their services. The pad material is expended over the service life.
Rear pads have less material than fronts, so they start at a disadvantage. The rest is up to MB regarding front-to-rear braking bias, pad chemical composition and use of electronic assist systems.
p.s. Separately, energy absorption during braking is one of the great benefits of hybrid and electric vehicles. To be clear, I am a petrol-head. But I do appreciate the engineering behind regenerative braking for hybrids and EVs.
@threeMBs compare AMG front pads and rear pads in the same photo. Note the area difference front and rear. Note the thickness difference front and rear. We are talking about pads here.
Rotor design is anecdotal for this conversation. A wider (thicker) rotor tells you it has been designed to absorb more energy than a thinner rotor. Best measurement of all is rotor weight. It's an energy thing.
The quantity (cubic volume) of pad material equals the amount of energy that will be converted from kinetic to heat as the vehicle is decelerated. Pads die and go to Heaven when performing their services. The pad material is expended over the service life.
Rear pads have less material than fronts, so they start at a disadvantage. The rest is up to MB regarding front-to-rear braking bias, pad chemical composition and use of electronic assist systems.
p.s. Separately, energy absorption during braking is one of the great benefits of hybrid and electric vehicles. To be clear, I am a petrol-head. But I do appreciate the engineering behind regenerative braking for hybrids and EVs.
Last edited by chassis; Feb 6, 2022 at 02:38 PM.
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@threeMBs compare AMG front pads and rear pads in the same photo. Note the area difference front and rear. Note the thickness difference front and rear. We are talking about pads here..
What I do not understand (since I do not have these cars nor experience with them) is why do "base" 350s with basically identical diameter sized front and rear rotors (even though fronts are much thicker because they are ventilated) have similar disproportional front/rear pad wear as 63AMGs? The difference in pads size can not be anywhere close to the 63AMGs front/rear pad size difference.
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2013 ML550 US spec. Air+Offroad pkg
My ML550 is a very early 2013 with the larger drilled and vented rotors all the way around (think it is the AMG setup). Rears burn out every 20k miles, fronts are still original with 80% life left after 60k miles. Fronts are larger since they should be taking the brunt of the heat and friction in braking, but yet it is the rears wearing out. Again, I dont have active lane keeping, and seldom use cruise, and no active braking distronic. Just seems that shouldnt happen.
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My ML550 is a very early 2013 with the larger drilled and vented rotors all the way around (think it is the AMG setup). Rears burn out every 20k miles, fronts are still original with 80% life left after 60k miles. Fronts are larger since they should be taking the brunt of the heat and friction in braking, but yet it is the rears wearing out. Again, I dont have active lane keeping, and seldom use cruise, and no active braking distronic. Just seems that shouldnt happen.
Rear pads for 63AMGs wearing out even faster than for other W166s because they use very high performance grippy GG friction compound (unlike FF for others) and in addition are 2mm thinner in the pad portion to begin with. Many report 8K miles or less with 63AMGs, especially those with heavier GL/GLS.
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From: unbegrenzt
2017 GLE350 4MATIC
No need for photos, I have two AMG cars (ML63 and GLE43 I just converted to 63s brakes) with these (15.4"/13.6") brakes in my garage. I am not disagreeing on significant rate of rear pads wear vs. the fronts for 63AMG cars. Front rotors and pads are significantly larger. Though I have to say that when DAP and Active Lane Assist(ALA) are not used at all, the wear difference front/rear is negligible in my experience - I get about 16K miles on both front and rear pads (about 8K miles on rear with DAP and ALA on at all times).
What I do not understand (since I do not have these cars nor experience with them) is why do "base" 350s with basically identical diameter sized front and rear rotors (even though fronts are much thicker because they are ventilated) have similar disproportional front/rear pad wear as 63AMGs? The difference in pads size can not be anywhere close to the 63AMGs front/rear pad size difference.
What I do not understand (since I do not have these cars nor experience with them) is why do "base" 350s with basically identical diameter sized front and rear rotors (even though fronts are much thicker because they are ventilated) have similar disproportional front/rear pad wear as 63AMGs? The difference in pads size can not be anywhere close to the 63AMGs front/rear pad size difference.
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Understood, it just the front/rear difference for 63s is much greater. While rears are basically all the same (since all use 1 piston TRW calipers) 63s front pads are probably 50% larger than others front pads - supporting 3 pistons (on each side) in line vs. 2 pistons in line.
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2013 ML550 US spec. Air+Offroad pkg
So I guess, to summarize, I've owned and worked on cars for 40 years, and the front brakes always wear out faster or at least at the same rate as the rears on all cars I've owed, until this ML. Now this ML blows thru rears like crazy, but front ones will apparently last over 100k miles, which is just SUPER odd to me. What I'm gathering from this thread, is that this is pretty much normal with the ML then, and not to worry about something wrong with the brake system? I would think MB would engineer rear brakes to be a little beefier so they would wear closer to the wear rate of the fronts.
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2013 ML550 US spec. Air+Offroad pkg
Yes you can...so long as they are not thinner than tolerance. Dealer will tell you they are not reuseable, but they are.
