uptownman

Hi All,
Dealer is replacing all brake disc and pads on my C63 since there was a vibration when braking at highway speeds...
My question is, any proper or suggested procedures to break in or bed in new brakes?
Thanks!

CPD SLK

There should be a bedding procedure for those pads and new rotors...usually involving a few hard stops from 50-65 miles per hour something. I'll wait for others to chime in. I'm not really sure, but at least you know it is something like that. Sounds like warped rotors!

zibby43

In a nutshell, you'll want to do several medium effort stops and a couple of hard stops from different speeds.

Try to make roughly 5-10 stops from approximately 35-40 mph with medium pedal pressure.

After that, make a couple more harder stops from around 45-50 mph. Lift off the pedal just shy of coming to a complete stop. After you've completed all of your stops, park the car somewhere for around 25-30 minutes without giving the brakes/pads a chance to cool down (i.e., park right after doing the stops without driving around and allowing the air/wind to cool the brakes).

That procedure has always served me well.

uptownman

Thanks Zibby!

Critter

Let your mom drive the car for 200 miles then the brakes will work properly. Millions of miles have been put on cars from drivers that just drive "normal" and get thousands of miles out of their brakes. Avoid hard stops to start with for at least 200 miles.

zibby43

You're welcome! Hope it works out well for you bud.

Millions of people also drive their cars without following a break-in procedure too. Doesn't mean that the break-in or bedding-in (in the case of new rotors and pads) procedures are worthless.

Personally, I don't rigorously adhere to the manufacturer's recommended break-in procedure (I follow it somewhat but am not afraid to let it rip after the car's fluids get up to operating temperature).

That said, a proper brake bedding proecedure does help to optimize how the pads mate with the surface of the rotor. Bedding in ensures that a uniform/even layer of the pad material is transferred to the surface of the rotor.

Doing this can help to prevent squealing - which is a common occurrence in big brake kits (e.g., the Brembo systems used on AMG cars) that are not bedded in properly.

roadtalontsi

all of this is crap. The dealer tech should seat them for you. If the brakes feel crappy once picking it up. On a safe discreet road run up to about 100 and do a panic stop. drive around for a few minutes to let them cool and do it again. You should notice a substantial improvement in stopping power and needed pedal effort. I've done this on thousands of brakes. This is how it's done. I dont care what anyone else says or tells you. If your rotors warp in the future it's because they were going to warp anyways. These brakes are great and typically a normal driver can get 50-100k out of a set of rotors but some, especially ones that track their car wont get anywhere near that. I replaced a set of rotors on a c63 b.s. at 12k miles because they tracked the crap out it. The slr brake bedding procedure is to go to 150mph+ and panic stop like 5x consecutively without letting them cool because they are carbon ceramics.

Diabolis

As roadtalonsi said, you want to do a couple of full-on panic stops from high speeds, allowing the brakes to fully cool down afterwards. That's the only way to bed them in properly.

What is even more important however is that you find a piece of road where you can (a) do it safely and (b) without getting caught. Going to jail and losing your licence is a much more serious problem.

zibby43

You're saying what I said was crap? If not, ignore this post but you suggested virtually the same thing, except at speeds of 100 mph.

I've never seen anyone recommend speeds that high. I think speeds like that are going to cause more harm than good. Then again, that is based on everything I've ever read or been told about bedding in brakes for STREET cars.

This is a little different than the first procedure I recommended, but it is from a reputable source:

"1) From 60mph, gently apply the brakes a couple of times to bring them up to operating temperature. This prevents you from thermally shocking the rotors and pads in the next steps.

2) Make eight to ten near-stops from 60mph to about 10-15 mph. Do it HARD by pressing the brakes firmly, but do not lock the wheels or engage ABS. At the end of each slowdown, immediately accelerate back to 60mph and then apply the brakes again. DO NOT COME TO A COMPLETE STOP! If you stop completely and sit with your foot on the brake pedal, you will imprint pad material onto the hot rotors, which could lead to vibration and uneven braking.

3) The brakes may begin to fade after the 7th or 8th near-stop. This fade will stabilize, but not completely go away until the brakes have fully cooled. A strong smell from the brakes, and even some smoke, is normal.

4) After the last near-stop, accelerate back up to speed and cruise for a while, using the brakes as little as possible. The brakes need only a few minutes to cool down. Try not to become trapped in traffic or come to a complete stop while the brakes are still very hot.

5) If full race pads, such as Hawk DTC-70 or Performance Friction PFC01 are being used, add four near-stops from 80 to 10 mph."

And by the way I didn't say anything about warping.

Quadcammer

this is correct.

100mph panic stops are wholly unnecessary and generally retarded.

Critter

Zibby, you seem to forget that the 63 has drilled and slotted rotors, the slots in theory will shave the pad off each time it is applied to the rotor to allow a "fresh" surface, and reduce glazing of the pad, the holes allow any "gas" created to be relieved between the pad and the rotor.
If you are "bedding" the pads and new rotors to the point of strong brake smell or smoke coming off the brake assembly, IMO, you have done more potential damage to the pad than they were manufactured to withstand, at what temp does the glue holding the pad material to the backing plate give way? Now riveted pads are a different and are manufactured to withstand more rigorous braking demands. If you are running stock pads from MB then all the 100mph stops and numerous hard stops will just reduce the length of service and increase the dreaded squeaking/squeal as you will actually bake the pad material harder. IMO

Diabolis

From StopTech:

In general, bed-in consists of heating a brake system to its adherent temperature to allow the formation of a transfer layer. The brake system is then allowed to cool without coming to rest, resulting in an even transfer layer deposition around the rotor circumference. This procedure is typically repeated two or three times in order to ensure that the entire rotor face is evenly covered with brake pad material. Sounds easy, right? Well, it can be if you have the proper information.

Because the adherent temperature range for brake pads varies widely (typically 100°F-600°F for street pads and 600°F-1400°F for race pads), each bed-in needs to be application-specific. One could try to generate a one-size-fits-all procedure, but too little heat during bed-in keeps the material from transferring to the rotor face while overheating the system can generate uneven pad deposits due to the material breaking down and splotching (that's a technical term) on to the rotor face.

In summary, the key to a successful bed-in is to bring the pads up to their adherent operating temperature in a controlled manner and keep them there long enough to start the pad material transfer process. Different brake system designs, pad types, and driving conditions require different procedures to successfully accomplish the bed-in.

Now, I do track my cars occasionally and use higher-temperature pads than most, so in order to get the pads to the temperatures where material transfer to the rotor starts to occur, you DO have to make panic stops from considerably higher speeds than 60 mph (100 km/h). I do concur however that with OEM low-temp street pads the temperatures and thus speeds needed would be lower.

Diabolis

You are always going to get brake smell and some smoke when they're new. You're simply burning off the paint used for markings, excess pad resin, various coatings from the manufacturing process and some of the anti-squeal grease as you bring everything up to temperature the first few times. It is perfectly normal.

I have never heard of anyone permanently damaging half-decent brake pads due to heat. If the pad is cracked, chances are you have a faulty caliper that is exerting uneven pressure across the pistons. You're much more likely to damage the caliper from serious overheating than the pad itself. This also goes for the friction material separating form the backing plate, which I have only seen once on an old Ford van that had been sitting for a number of years without being driven.


P.S. As for cross-drilled rotors, the holes are now only there for looks. Not only are they completely useless from a practical standpoint, they provide worse braking performance and weaken the rotors considerably. Solid or arguably slotted is all you'll ever need both for performance and longevity.

zibby43

I'm not the one that recommended 100 mph stops for bedding in stock steel rotors and pads. But these cars are tracked and stopped consistently from much higher speeds than that so I'm sure that with the proper technique (on the driver) and proper fluid, the brakes would be just fine.

No, I haven't forgotten about the drilling and slotting of the rotors. Your explanation is not quite how drilled/slotted rotors work though. Both the drilling and slotting primarily serve a venting function with respect to venting any hot gasses away from the brakes.

Whenever you're breaking in new pads/rotors, you want to create a strong/uniform initial transfer layer of pad material on the rotor surface. Naturally the slots the wear the pad more but they do not start the transfer process over and over again.

Not to sound dismissive but you can easily research and verify what I just said above. Companies like Brembo, Stoptech, AP Racing, etc. all advocate bedding in procedures on their drilled/slotted rotors. There is a difference between the application of the initial transfer layer on the rotor and shaving off fresh pad material on the pad itself that "mates" with the layer on the surface of the rotor (which was originally applied by following the bedding in procedure that involved getting the rotors hot enough to facilitate the transfer in the first place).

zibby43

Agreed.

I just don't see what you didn't like about my initial explanation? It was nearly identical to yours, except my speeds were lower since we are dealing with stock pads, fluid, rotors, etc.

Diabolis

Hi Zibby,

I just re-read the entire thread - I only meant to second roadtalonsi's post that for higher-temp brakes you usually need to do a couple of full-on panic stops from considerably higher speeds than 60mph to get them hot enough for material transfer, NOT that what you wrote earlier was crap. Your post was spot-on, and I do apologize if it came across that way. My bad. I disagreed with one of Critter's posts about the smell and the smoke, which is normal with new brakes.

Cheers,
Doug

zibby43

Gotcha! No worries man. Appreciate the clarification.

roadtalontsi

ok not all of it was crap
Just dont be scared guys. They need to be nice and hot to seat. Not for long periods of time but some quick little blasts enough to get heat in them. Let them air cool for a 30seconds and try again - you'll know when they are working properly because you'll be like holy **** these brakes are amazing. The alternative would be using gas and brake at the same time but that doesnt work on benz's it'll think you died at the wheel or are trying to be stupid and shut the throttle off. As anyone knows that has truly tracked their car there is a reason for cool down laps and why you dont set your parking brake afterwards. You in no way need to get them that kind of crazy hot.