ronin amg

So it's been a while since I changed my brake fluid to Castrol SRF [6,600 mi.] but it's time again.
After taking a spirited cruise on a tight canyon road I got the rear diff malfunction warning, traction control malfunction that turned it off completely.
It seems the traction control is so aggressive it can cook the high temp brake fluid all on its own even running up hill.

Yeah the road was dusty and rough but I am never hard on my brakes even on the down hill...
I brought it to the dealership and it seems there is a recall for the rear diff wiring connector and a replacement part has been ordered and it will take two weeks to get here.
They also turned off the traction control completely and gave me the car back and said to take it easy until the fix is in...sad

Mercedes ya gotta make lighter cars or design a better traction control setup..

DriveAMG

ronin amg

I never track my cars so I have no experience to base an opinion on your pads condition, all I do know is being light on the brakes going up hill on a dusty road and winding up with brake fade is not due to braking but due to the traction control intervening and cooking the brake fluid..
I would rather have a decrease in power than a loss of braking for traction control..

E634Me

Carac

An aside. If you do track days make sure to manually disengage the parking brake when you park because it will rest the pads against the hot rotors.

DriveAMG

Carac

No disrespect meant, it was a comment for anyone reading that might be interested in doing a track day with CCBs that might be reading. A good rule of thumb.

DriveAMG

E634Me

They also taught us to do this at the Mercedes AMG Academy. Have lots of track experience on motorcycles, but not so much with a car and wouldn't have thought about it if the Instructors hadn't pointed it out. The Mercedes sets the emergency brake automagically under a number of conditions so we were frequently checking to make sure it wasn't engaged. Likewise while waiting our turn to take a run at a course segment we were instructed not to hold the car with our foot on the brake - put the car in park instead (and of course make sure the emergency brake wasn't set ;-) )

ronin amg

There is no need to do the no-parking brake thing on the street or canyons with ether steel or CCB brakes. This is a traction control issue.. please stay on topic.

DriveAMG

Dagger9903

Was there a direct relationship between the rear diff wiring connector recall and brake fade? Or is it the traction malfunction that's related? Maybe the rear diff issue is related to the traction malfunction, and the brake fade is an issue but unrelated to those issues?

Side question, have you looked into options to improve the brake fade issues? Not sure what that'd be - SS brake lines?

Also, I assume the traction control is primarily using the rear brakes? If so, that's interesting because when actually stopping probably 70% of the stopping power comes from the front brakes, so I'd think that balances out a bit on pedal feel. Maybe a bad assumption though.

E634Me

Sorry, thought it was a CCB brake fade issue, which it seems was most likely cause by aggressive activation of traction control - or maybe even by a failing TC system.

But, regardless of whether the brakes and brake fluid were getting cooked by heavy use of brakes to slow the car or by frequent TC activity, the brakes themselves clearly are getting really hot.

So the caution regarding use of the E-brake would seem apropos even for this canyon driving scenario as the brakes must be really toasty hot.

Still, as noted regarding my experience with my underpowered Jeep, frequent TC activation clearly leads to premature brake wear and is something we should keep an eye out for because the E63 does easily put down more power than the wheels can handle, leading to the TC light coming on regularly.

Have you, or anyone, done much driving with TC off but still in all wheel drive? Not drift mode, but just holding down the TC button past sport mode into TC off mode.

Curious about how easy it is to get the car out of shape and recover given the help from the front wheels?

ronin amg

I honestly have never driven the car with the TC off and am waiting for the replacement parts to show up.
I will flush the brake fluid and replace it with Castrol SRF again and then experiment with the TC on/off handling in the canyons. It would be nice if we had the TC control knob like in the GTR.
I'm gettin the feeling that AMG knows something about the brake fluid cooking due to TC..

Or I could just drive slower..

E634Me

Clearly Mercedes is happy to put these cars into the hands of the press and if not encouraging them, certainly expects them to show the cars in various degrees of tire smoking sideways action.

It's what sells AMGs.

We then have a reasonable expectation that the car should be able to be driven in a spirited manor without melting the brakes due to TC issues.

Even Mercedes' own "Get the F out the the way" commercial plays to this expectation.

On a turn near my office on the way home I have had the car step out in a lively fashion while in Race mode. Fairly wide intersection which typically I exit in 2nd gear and roll into the power pretty hard. Fairly predictably the car will light up and get a little sideways, but on occasion it has jumped fairly sideways pretty quickly before TC, torque vectoring to the front wheels, and countersteering reins it back in.

Would be interesting to do it with TC all the way off, but will save that experiment for a wide open space with plenty of room in case it gets more interesting than expected. Don't want to end up in a Mustang-esc youtube video ;-)

tonecas

this happens with CCB??