victor63

I am experiencing a shuddering and Vibration when braking

After this i replaced both front discs and pads (ZIMMERMAN) twice from FCP and tried to run them in as best i could without overheating or keeping my foot on the brake when at a junction or lights etc. Initially i didn't notice the issue but i was careful on my brakes for a good 400 miles.

The vibration is back again - starting from 70mph ,now down to 50 mph, I can fell pulsating when breaking from those speed - under 50 is ok,

mechanics cannot find a possible solution;

was this a common issue with zimerman amg break rotors?

catmandoob

Don't know of Zimmerman having issues but I will say my wifes W204 seems to warp rotors fairly quick too, I've always chocked it up to her braking style.

Maybe toss on a set of brembo 2 piece and see what they do. I tossed a set of girodisc on mine and never an issue and i have about 3k miles on them now.

It honestly sounds like warping rotors either from heat or uneven braking from calipers, something that is causing some drag to present an excess heat and cooling cycles.

But if it's warped rotors even at low speeds if you hit the brake hard you should feel the lovely shudder and vibration steering wheel feel so to speak.

Diabolis

Warped (very likely front) rotors 100%. When you warp one-piece steel rotors that is exactly what happens. And no, just because it doesn't happen below 50 mph does not mean that it isn't the rotors - in fact, that is exactly what happens. Metal expands when heated - when they are cold they are fine. When you start putting some heat into them - as in a stop from 50 mph or higher - the steel expands, and unlike with a two-piece floating rotor where the ring is separate from the hat and can expand radially in both directions (up and down), a one-piece rotors can't do that because the hat is part of the same piece of metal (which it is also in contact with the the wheel and hub assembly which essentially act as a big heat sink) and the metal expansion is uneven resulting in portions of the ring part of the rotor bowing out laterally. When it cools off the metal shrinks and a cold rotor looks perfectly fine.

victor63

I changed the rotor twice for the last 6 month. both zimmerman. So are you suggesting to change to two piece rotor even for a non -p30 break would help ?

Dogtag114

There is a camp that says rotors rarely warp unless at end of life with heavy, repeated track use. They say that it is more likely uneven brake pad deposits on the rotors from continued light braking on the street.

My wife's explorer gets this due to her driving style and I occasionally go out and do braking runs and it goes away for 6 month until it builds up again. I do 6-10 runs with 100% braking from 55-20 with 20-30 seconds between. These pads don't like heat so the braking fades quickly, but the rotors get cleaned.

roadkillrob

I would try one of the brake bedding in procedures and see if it helps your issue https://www.powerstop.com/resources/...-in-procedure/

Diabolis

If you have a non-P30 car, OEM one-piece rotors WITH OEM PADS will work just fine and never warp. The aftermarket pads likely have a different friction coefficient or thermal conductivity and are quite possibly hot-spotting the rotors resulting in said vibration. I have had numerous rotors warp with aftermarket pads but work perfectly fine for many years with OEM pads under the same braking / operational conditions.

The people in said camp have simply never experienced rotors warping for any number of reasons - and with OEM pads and rotors, they don't warp even at end of life with heavy, repeated track use. You just burn up the OEM pads, which then reek (even when cold) and simply disintegrate after two track days - but they will NOT warp the OEM C63 rotors.

While uneven pad material build-up can most definitely cause vibration when braking, that particular cause of vibration does occur at all speeds (as opposed to higher speeds only) as the rotors have uneven pad deposits, and is furthermore very easily remedied by an "Italian tune-up", i.e. several hard stops from higher speeds which is enough to scrub away any such deposits as you have yourself discovered.

Absolutely - you need to condition the new rotors and properly mate the rotor to pad surface, but that procedure only needs to be followed when you are putting on new pads and even more importantly, new rotors which properly heat cycles them. Allowing the rotors to properly cool off afterwards by driving for a few minutes without applying the brakes and thereby hot-spotting the new rotors is absolutely essential (which is what happens if you just stop the car and the pads which are now heat-soaked apply heat to the portion of the rotor that is under the pads while the rest of the rotor cools off), and actually does extend the rotor life. After they've been on the car for a hundred kilometers however, they're fully bedded in (hot-spotting and all if a proper bedding in procedure hasn't been followed).

Another thing that warps rotors is taking the car through a car wash (or washing it yourself and spraying water on the wheels) when the brakes are still hot. Works every time.

I have personally easily gone through several hundred rotors and twice to possibly three times as many pads on my various cars over time (the vast majority of which have seen at least some track use and have gone through numerous both aftermarket and OEM rotors and pads) - not to mention that at the P-car shop we probably replace ~40 rotors a week as we are one of the authorized PCA tech inspection centers and cater to a lot of track junkies - so all of the above is pretty much as statistically significant as you can get. Last but not least, the saying that you get what you pay for holds 100% true. A C63 is a heavy and powerful car that is quite hard on the brakes. Cheap rotors and pads may work fine on your grandparents' Toyota Tercel - and they even work on my old ex-Honda Michelin Challenge Civic race car on which we just replaced the read drum brake shoes for the first time since 2004 - but not on a 4000 lb, 500 hp beast once you get it up to speed.

blurred

There is a reason that most heavier cars with large diameter brakes use a 1.5pc/2pc rotor setup. The reason is the larger rotors will "warp" very easily even with moderate use. If you used the Zimmerman 1pc rotors you will likely always have this issue. There are also a number of bushings up front (tie rods will be worst for shuddering) that wear out and can introduce some front end wobble (tie rod ends will allow the wheels to shake laterally under braking as an example, but your fresh rotors solved the problem it seems).

Your best bet as already suggested is to use the p30/p31 rotors because they should have been spec'ed for all c63's due to the rotor size. You should also service your calipers as a sticky piston can easily accelerate these issues.

GRP

I have used Zimmerman front one piece with Hawk pads - flawless.

Unless there is a batch of flawed Zimmerman discs out there then it is the bedding on or other?

roadkillrob

A shot in the dark but I have experienced over torqued lug bolts or unevenly torqued can cause an issue with one piece rotors so just throwing that out there in case it could be a factor.

Diabolis

Which Hawk pads? HPS work great with no issues. HP+ could possibly warp them depending on use. DTC-70s will definitely warp the rotors the moment you warm up the pads (they have no bite whatsoever when cold).

NZ-Merc

Plus 1 for above comment.


When mounting new discs it is important to make sure the wheel hub flange is shiny and smooth, I use sand paper for this then apply light smear of copper coat across the surface to stop corrosion.

Make sure the back of the wheel mating face is also cleaned up and torque up the wheel nuts.

I dont get all hung up with break in procedures just drive it normal but allow longer stopping distances for 2 weeks.

If you are doing some sort of break in procedure which involves getting the discs abnormal hot while still new you could very likely run in to warping issues.

GRP

HPS

Diabolis

My point exactly.

Diabolis

The reason why unevenly torqued wheel bolts (or lug nuts) may result in warped one-piece rotors is that the portion of the rotor where the corresponding wheel bolt is considerably tighter that the other ones will have a higher surface area (on a microscopic scale) in contact with the wheel, which acts as a large heat sink - so the rotor unevenly heats up and cools. It is precisely the opposite of parking the car with hot brakes, but the cause is exactly the same - uneven heating and cooling of the (one-piece) rotor.

victor63

2023 update -

After replacing front caliper, Rotors, and Pads. front right wheel bearing. The vibration went off during normal high speed cruising. However, the break vibration & pedal shudder can still be flt when breaking above 50 mph. most noticeable at 50mph. incredibly annoying. Any other ideas from yall. please throw them my way

Diabolis

What rotors and pads did you use (the replacements)? OEM or aftermarket?

BLKROKT

If all that brake hardware and wheel bearings were changed, you’re feeling something else and confusing it with brake vibration. I’d start looking at control arm bushings, ball joints and other suspension components next.