We have a 2011 GL450 with 111k miles on it. We bought it in the summer of 2019 I think with 100k miles. Mostly local driving but occasional out of state trips. The brake sensor warning is coming on and visually inspecting the brakes, it appears the rears are the ones which are 1/2 as thick now. The fronts appear to still be 3/4. So I intend to replace the rears first. Checking the rotor with my finger, there is definitely an outer lip. I assume these are the original rotors, but likely not original brake pads (wild guess).

Anyways, originally was just going to snag the brake pads at my local O'Reilly store and got Wagner Thermaquiet Semi Metallic pads for like $70 but then realized maybe I need to replace the rotors while I am back there given the miles on the car. The rotors at that store are like BrakeBest or something weird. I usually buy off rockauto or eeuroparts. Eeuro pushes Brembo for the rotors and pads, and Rockauto has more of a selection but including Wagner which states (OE).

Also read on this forum people tend to prefer ceramic. Is there anything wrong with going with the Wagner pads and rotors for this, given we have put 11k on the car in 2 years? (granted, covid related)

EDIT -

Reading up a bit more, sounds like there is often a consensus on Akebono for the brakes (ceramic) , and Brembo for the rotors. Interestingly, on Eeuroparts, the entire kit for the rear is like $192, but if I buy the parts separately I can get them for $167 lol.

 

I've found the ceramics along with the GL450's caliper requires more effort to stop but the pads and rotors seem to last twice as long than with the semi-metallics. Love the ceramic pads on my GL63 but the massive rotors and calipers make up for the lost bite that the GL450 suffers with the ceramic pads.

Yes, Wagner is a decent brand.

 

I was in the same situation as you, not that long ago. I replaced the rear rotors and pads with Brembo/Akebono ceramics, but left the fronts alone as there is still plenty of pad left. With just the rears replaced, I don't feel any difference in the bite/pedal/stopping, but I also don't drive the GL like a race car. I generally break earlier than I would with a car. As a result, I gradually scrub speed over a longer distance.

I went with Akebonos based on the reviews here. For rotors, I've always opted for Brembo or Zimmermann in the past with my other cars, and decided to continue in that spirit with the GL as well.

I have a set of Brembo rotors for the front as well, but not sure if I will do Akebono or Brembo pads on the front, yet, when the time comes.

 

Good to hear. Yea, I might go with that combo. The fact Eeuroparts pairs them together in their "set" indicates they view them as a correct combo as well.

 

The advantage of the akebonos is that they are virtually dust-free. If you don't care about brake dust on your wheels, the Wagner pads should be fine. I wouldn't lose sleep over rotor brands unless you're doing something that is especially hard on the brakes especially at the rear since they don't do as much of the work as the fronts.

 

Why are the rears so much more worn down than the fronts then?

 

Unless you are absolutely certain that the fronts and rears were replaced at the same time, you can't really say that the rears are wearing faster. Stopping power comes more from your front brakes than the rear due to weight transfer while stopping. Mild braking can be about 55% front while aggressive braking can be up to 70% front (fronts doing more than twice as much work).

There are a few scenarios where the rears will end up wearing faster, especially due to the fact that they are generally smaller than the front brakes. The first is towing heavy trailers, and the second is when carrying heavy loads in the back. The least likely scenario is an improperly balanced braking system. You might be able to test this by turning ABS off and braking hard on wet or dirt road (do this with plenty of room and not too fast!). If your rears lock up much earlier than the fronts, your brakes are improperly balanced and can lead to your car going out of control (think unexpected drifting).

In any case, your brakes will not wear at the same rate since there are a myriad of factors affecting brake performance and thus wear.

 

The general consensus is that the rear brakes are used to keep (or slow) speeds with cruise control, as well as, used during any bouts of traction control. Limiting the use of cruise control or pressing the traction control button once, should turn on sport mode and allow for driving without the use of the rear brakes without you depressing the brake pedal.

*Not liable for anyone turning off traction control and trying to drift around corners like a character in the Fast and the Furious and smack into unknown objects

 

Short and to the point ..... because the fronts were changed more recently than the rears.

 

Whatever you do, bed in the pads to the rotors. It's worth it; the grip of the pads on the rotors is higher and pedal effort is reduced. Wear rises significantly, too.

Note that ceramic pads don't not make dust. it's just that the dust they make is non ferrous, so it doesn't oxidize and stick to the wheel in atrocious dark coats.

I ordered some Detroit Axle pads and rotors. Ceramic. Like $120 for the whole set. I'm mighty interested to see how long they wear. They seemed fine on my daughter's Jeep, so who knows.

 

say what? Never heard of this

 

Not many do. There are articles on it, and better pad manufacturers will instruct you. Basically, you are using heat to transfer a layer of pad material on to the rotor. You do this by making a series of very hard stops, 60-5, right in a row, not bringing the vehicle to a stop, and then accelerating hard back up to 60 and repeating about four times. Done correctly you end up with a gray layer on the rotors, no longer shiny. This makes it that the pad is essentially rubbing on another pad, rather than on the raw iron. This forms a very long-wearing adhesive layer on the rotor, and better braking performance. It's weird, but it works, if you do it right, and it's a shame no one does. I think I have seen nice gray rotors on one street car in my life.

The risk is overdoing it, in which case you end up with cementite inclusions that basically never go away. I know from personal experience; my front rotors developed blotches of pad material and the uneven heat caused surface cracks to start forming in the rotor. I ran semi metallic pads for a while, scrubbing the spots off, but they sort of returned. Now my rotors look kind of like leopard fur but hey - it still works.

With the bedded-in pads, even with my abuse, the pads (front) have lasted a simply ungodly amount of time. I have 120k miles on them now.

Follow the instructions; you can always bed them in more, but can't less. It's also key to not bring the vehicle to a stop with hot rotors (that's why it's 60-5, not 60-0), or the pads will literally leave a pad shaped imprint. Go out on a Sunday morning on roads you can do these stops on without freaking people out.

I suspect ceramic pads bed-in better than semi metallic. The metal wears away the bedding layer.

 

Oh damn that is news to me.

I just assumed, always, hard stopping would warp my rotors and wear the pads down quick. which is probably true in the long haul) but for some reason it has always been in my head that if I ever had to brake really quickly, I'd likely be 'ruining' the shape of my rotor or brake quality.

This is embarrassing to admit. I have an altima with push start (2008). You have to depress the brake to start the car but mine was no longer working. I was having to push it very hard. So I ordered the necessary part and went to fix it. I remember fitting it into a slot and you had to rotate it / lock it in or something. I found out, the hard way, I didn't do this right. I immediately felt like the brake pedal was extra stiff...but I figured it was due to the new part. I got driving about 1/2 a mile and my car was slowing down...do the point where I literally had trouble progressing forward. Got into a parking lot and luckily parked. Had to get picked up that morning cause I was unsure of what went wrong and didn't have time to fiddle with it. Got off work, and tried to drive it home. I got within 200 feet of my house but had to park on the side of the road cause of the smoke my tires were creating. I remember getting out of the car and my rotors were basically lightly glowing.

I was stumped...but re-checked the part I changed. Undid it, re-set it back in place and turned..but this time, turned more..and it locked into place. Previously, I prematurely stopped turning which forced it into a more depressed position vs the locked position.

The heat from the brakes and rotors were causing them to seize up together lol. I feel so stupid for typing this all out..but it was definitely a learning experience for me.

 

Bedding is definitely a good idea. I just put a set of ceramic rear pads on our Mazda, and the pads actually came with bedding instructions. 5 hard slow downs from 40 - 5 mph followed by several minutes of driving with no stopping and as little braking as possible. I've always done something similar with new pads with good results.

 

Understandable. Thanks for sharing, though: If we share our mistakes, others can learn.

Regarding warping: Did you know that there essentially is no such thing? Rather, there are uneven friction areas. In particular, cementite inclusions stand proud of the surface and make more friction and more heat and ... more cementite. So there is not warping, but uneven thickness and uneven rotor composition.

I had large deposits on the rotors. I scrubbed them with semi metal pads and they got much better; I used to get steering wheel vibration when I would brake, but now, with the "leopard spots" I hear a kind of groaning noise. It's actually somewhat entertaining. All this because I overdid the bedding-in procedure. I'm the guy that thinks one Tylenol is good, so ten must be better, ending up in the hospital needing a new liver.

You can always bed-in more, but you can't reverse bedding-in too much.

I think pad manufacturers don't instruct on bed-in because 1) it's easy to get wrong and then you blame the pad and rotor manufacturer, and 2) if you don't do it, worst case is you buy more pads.

 

Instead of engaging in the near impossible and certainly ridiculous effort of attempting to maintain a German vehicle with third world parts—those found at USA flaps and mail order sources like Rock Auto—why not actually price genuine Mercedes components. Mercedes actually has a value line group of parts. There are several dealers selling online at discount prices. My favorite is ...

http://www.mbdirectparts.com

You can likely find a closer source just by searching.

Next best is searching for German after market parts at sources like

fcpeuro.com
autohausaz.com

Then, it’s good to understand that with most Mercedes both pads and rotors are usually changed together. The wear limit is 2 mm and if you can feel a lip at edge of rotor, that’s at least 1mm on that side and obviously the same wear has happened on the inside of the rotor too.

As for “bedding in” ... since your rear brakes only do about 25% of your braking, I’d not get too obsessive about it.

Your biggest problem replacing rear brakes is getting emergency brake adjustment correct. Good luck finding a way to spin the rotor to check ... you’ll likely require ignition on to keep transmission out of park. Then something to keep vehicle from rolling off jack.

 

While your pricing genius Mercedes parts, why not purchase from FCP Euro and youll never have to repurchase that part again for life with the lifetime warranty.

 

So much to unpack. I wonder if the Bilstein shocks I bought at Rock Auto are "third world".

Aren't Mercedes OEM brake pads semi metallic? Isn't that why the front wheels dust up so horribly? I kind of like my third world ceramic pads.

There isn't much harm done in fiddling around with different brake pads. Online forums tend not to be populated by folks whose MO is going to the dealership saying "fix car pls".

But to each his own. You do you.

The parking brake has nothing to do with the rear calipers. It actuates a drum brake inside the rotor.

It doesn't hurt to re-do the bed-in procedure. You probably won't be able to get the rear rotors hot enough to bed-in, however. I haven't tried.

 

My current project work in progress. Needed needed pads and rotors. Got a steal of a deal with some ML63 Calipers like 3 years ago.
so I’m in the process of installing.

Front 07-11 ML63 calipers
Front 12+ ML63 drilled/slotted Rotors 390x36
Rear 07-11 ML63 Calipers
Rear 07-11 ML63 dimpled rotors


Before

After

 

That's great. Was it a direct bolt on?

 

[QUOTE=WaveyKat;8324675]My current project work in progress. Needed needed pads and rotors. Got a steal of a deal with some ML63 Calipers like 3 years ago.
so I’m in the process of installing.

Front 07-11 ML63 calipers
Front 12+ ML63 drilled/slotted Rotors 390x36
Rear 07-11 ML63 Calipers
Rear 07-11 ML63 dimpled rotors
/QUOTE]

Curious of the benefits of the ML 63 calipers. They look to be a similar design to the OEM, but look to be a monoblock type with 2 pistons. I can see the pads being changed without the need to dismount the caliper. Wondering what else the ML 63 calipers are hiding up their sleeve.

 

I have the Wagner OEx and they work GREAT. There's a relatively large mountain on my commute, which requires happy brakes.

 

I have always had very good results with either Lemforder or Febi, the rotors are always true and the pads seem to bed in well. A bit more expensive, but easier to do it once.