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Since I got the car (C300 2015) in sept 2015, I've had a few problems with the braking system. At about 10K miles, the pedal was pulsating when i pushed the brake pedal. Dealer changed 1 front disk because of a warping issue. Last november, the brake booster broke. Car has been 4 days at the dealership because they didn't have the part in stock. This morning exiting my driveway, I noticed the same pulsating issue. After driving for about 40 miles, I stopped at Starbuck and discovered a rusty stain on the disk (see picture below). Is it a sign of another warping issue? Or something worse?
Is there any other problem that I may think about? Seems weird that the sport disks of this car are that bad in term of reliability and durability. on a 30 000 miles car of wish 75% is on highway at normal speed without any abrupt or continuous braking.
Rust will develop after about of week of not driving with wet rotors. I always replace rotors in pairs, like replacing brake pads in pais. Once a rotor is thin, they tend to warp easily. Also if thermo shocked -- water splashed will warp a hot rotor.
Ceramic pads do not like a rusty rotor and will get contaminated from one.
I use the dirty OEM pads that don't seem to care if the rotor is rust or if the wheel is black from the pad dust.
Yeah I'm used of getting rust on the brake rotor, especially in winter time. However, normaly after a few miles of driving, the rust goes off and the rotors become clean and shiny. This time it's like if the pad isn't even touching this area of the rotor. The other 3 disks are all ok, but the front driver side one seems to create that pulsation I'm getting in the pedal when I brake.
Worth cleaning your discs thoroughly with car pro iron X... Then Re assess.
The ferrous iron patch may be causing the pulsing and although it will appear to rub off it creates areas of different friction coefficient which you can feel as pulsing.
i have written about this previously if you want to use search..
These rotors are a new kind of so called, hybrid type, the centre hub is pressed sheet metal and the outer wear surface is cast iron, the parts are then precision pressed together.
We are through Mercedes-Benz Global Training informed how delicate these rotors are, they are always shipped well packaged in pairs and you may never hit them or even tap them with any kind of tool, you arnt event supposed to carry the rotor by the centre hub.
Also, fitting aftermarket wheels, voids all warranty claims regarding warped rotors as Mercedes claim that only OE wheels give the correct and even pressure to the rotor between wheel and vehicle hub.
Thanks guys for your thoughts. I tried to wash the front rotors with brake cleaner this morning...the rusty spot disappeared partially but I still get the pulsation in the pedal, particularly at highway speed. Have an appointment at the dealer tomorrow morning...warped rotor seems to be the problem again. Makes me regret the luxury package...
What you're most likely feeling is uneven brake pad deposits and those are usually caused by heavy braking (high speed braking, constantly braking down hills, speeding up and slowing down in rapid succession) and then coming to a complete and total stop. The rapid braking heats up the rotors and the pads, the complete stop allows the pad to cool in one area on the pad depositing material in that one area. When the pad cools, it hardens so the next time you brake you feel that hardened area, then the smooth area that gives you that pulsating feeling.
That picture of that rusted area is exactly what I'm talking about, that's the one area that has the pad deposits on it. That's what's causing your pulsating.
To solve it, you can have the rotors "turned". Basically machined so that the entire surface is uniform, clean of brake deposits, and the same thickness all the way around.
Some suggestions to prevent it from happening again. Adjust your driving style such that you don't overheat your brakes so much. Downshift when going down hills. In 99% of hills or mountainous roads, I rarely use the brakes. Brake earlier and/or brake less.. this usually involves driving slower overall. If you've braked a lot and know your brakes are hot (because you can smell them), then avoid braking to a complete stop (keep the wheels rolling at 0.5 mph if possible) and give them enough time to cool so they don't imprint themselves on one area of the rotor.
Of course, because everything you read on the internet is true, right?
Do you even track bro?
In addition to the first technical white paper (from Stoptech/Centric brakes), check out these articles from other brake manufacturers and specialists... also from the internet...
Yeah, I race and I have measured several warped rotors using dial test indicators,
the problem with the W205 and W213 rotors is that it is not the cast steel warping, it is the press fit alignment of the rotor hub that gets out of place, but still, the outcome is the same.
Yeah, I race and I have measured several warped rotors using dial test indicators,
the problem with the W205 and W213 rotors is that it is not the cast steel warping, it is the press fit alignment of the rotor hub that gets out of place, but still, the outcome is the same.
Any thoughts on the complaints on the board of rotors and brake pads needing replacing at under 20k miles with OEM wheels and no track visits. This is now the new normal for Mercedes? What benefit are these new hybrid rotors to the consumer? 0.001% boost to fuel economy via weight reduction? Or just a manufacturing cost benefit to MB + additional service visit money?
Any thoughts on the complaints on the board of rotors and brake pads needing replacing at under 20k miles with OEM wheels and no track visits. This is now the new normal for Mercedes? What benefit are these new hybrid rotors to the consumer? 0.001% boost to fuel economy via weight reduction? Or just a manufacturing cost benefit to MB + additional service visit money?
They are much lighter, and more expensive to produce, the increased cost to the customer isnt that high.
Better acceleration, handling and fuel economy are the results, downside being that they are very delicate, it is possible to damage them if dropping a wheel onto the rotor while loosening the wheels.
Yeah, I race and I have measured several warped rotors using dial test indicators,
the problem with the W205 and W213 rotors is that it is not the cast steel warping, it is the press fit alignment of the rotor hub that gets out of place, but still, the outcome is the same.
Based on what you described, it still sounds like uneven pad deposits are what you're measuring. As stated before and in all those articles, are you sure you're not measuring uneven pad deposition caused by a misaligned press fit? After reading the statement again, I guess you are agreeing with me.
It's true that the outcome would be the same in that you'd feel vibrations but the cause, I guess, is what is up for debate.
The statement that helped me understand the problem the most was:
Rotors are cast in extreme heat — three to five times greater than the most aggressive braking situation. Physically “warping” a rotor would require a similar application of extreme heat, which is impossible.
Obviously rotors aren’t invincible. They can crack, break and develop irregularities that lead to pulsation, but all of those problems start to develop in other ways that need a technician’s touch.
I am very certain, I have turned a lot of rotors in my days and on the lathe it is easy to see how uneven the surface is.
Sure brake pad marks is a problem as well, but very often it is possible to brake them off.
There are tons of additional factors other than heat that could cause rotor issues, it is often not just heat itself causing problems, but combined with, different ambient temps, water, snow, ice, dirt, uneven wheel hubs, dirt between hub and rotor, dirt between wheel and rotor, defective brake pads, defective brake pad carriers, pads stuck in carrier, brake caliper piston siezing and so on, and so on.
01-16-2017, 07:44 PM
warped brake rotor? 2 times since Aug 2015!
on a 30 000 miles car of wish 75% is on highway at normal speed without any abrupt or continuous braking.
