Sticky breaks on cold start (2012 E350)
Thread Starter
Junior Member
Joined: Nov 2012
Posts: 46
Likes: 0
From: San Diego, CA
2012 E350
Sticky breaks on cold start (2012 E350)
Hello,
After my last service, I started noticing something strange with my break pedal.
Only after COLD starts, the break pedal "sticks" for the first 1/4 or 1/8 of an inch during the first few depressions. After the car is in motion, after I depress the breaks 6+ more times, the break pedal depression is smooth, same as it always has been.
Found two similar threads with this odd issue from other forums:
https://mbworld.org/forums/sl-class-...al-sticks.html
https://mbworld.org/forums/w218/4583...edal-feel.html
Anyone else encountered this issue?
Thanks!
After my last service, I started noticing something strange with my break pedal.
Only after COLD starts, the break pedal "sticks" for the first 1/4 or 1/8 of an inch during the first few depressions. After the car is in motion, after I depress the breaks 6+ more times, the break pedal depression is smooth, same as it always has been.
Found two similar threads with this odd issue from other forums:
https://mbworld.org/forums/sl-class-...al-sticks.html
https://mbworld.org/forums/w218/4583...edal-feel.html
Anyone else encountered this issue?
Thanks!
Senior Member
Joined: Apr 2012
Posts: 470
Likes: 8
From: Southern California, Orange County
2012 E350
Does it actually stick? like with no motion? Or does it just depress slower than usual??
Also, did you leave your car with the dealer over night? That's the only way to really get a "Cold" start on the car. If they check it out right after you bring it to them it won't be a cold start. Sorry if you have already done this, just checking.
Also, did you leave your car with the dealer over night? That's the only way to really get a "Cold" start on the car. If they check it out right after you bring it to them it won't be a cold start. Sorry if you have already done this, just checking.
Thread Starter
Junior Member
Joined: Nov 2012
Posts: 46
Likes: 0
From: San Diego, CA
2012 E350
Does it actually stick? like with no motion? Or does it just depress slower than usual??
Also, did you leave your car with the dealer over night? That's the only way to really get a "Cold" start on the car. If they check it out right after you bring it to them it won't be a cold start. Sorry if you have already done this, just checking.
Also, did you leave your car with the dealer over night? That's the only way to really get a "Cold" start on the car. If they check it out right after you bring it to them it won't be a cold start. Sorry if you have already done this, just checking.
Analogous to poking a hole in a piece of paper using a pen. First bit there is tension, after the hole is punctured, rest is smooth.
Did not leave the car overnight. Thing is, this issue only repros once, twice, maybe three pedal depressions after a COLD start. All of it has to be gauged through the driver's legs .... nothing is "visible" or "audible", thus can't be documented.
Will call the dealer tomorrow to see if something like this can be set up. Thanks for your advice!
Senior Member
Joined: Apr 2012
Posts: 470
Likes: 8
From: Southern California, Orange County
2012 E350
I am thinking maybe its just the brake fluids in the car being too cold? I am just throwing random guesses now and I actually have no idea if that actually causes it. It may lead you to something though?
MBWorld Fanatic!
Joined: Oct 2010
Posts: 5,141
Likes: 1,293
From: Southern US
2010 E550, 273 Engine: 2012 S550, 278 Engine
Hello,
After my last service, I started noticing something strange with my break pedal.
Only after COLD starts, the break pedal "sticks" for the first 1/4 or 1/8 of an inch during the first few depressions. After the car is in motion, after I depress the breaks 6+ more times, the break pedal depression is smooth, same as it always has been.
Found two similar threads with this odd issue from other forums:
https://mbworld.org/forums/sl-class-...al-sticks.html
https://mbworld.org/forums/w218/4583...edal-feel.html
Anyone else encountered this issue?
Thanks!
After my last service, I started noticing something strange with my break pedal.
Only after COLD starts, the break pedal "sticks" for the first 1/4 or 1/8 of an inch during the first few depressions. After the car is in motion, after I depress the breaks 6+ more times, the break pedal depression is smooth, same as it always has been.
Found two similar threads with this odd issue from other forums:
https://mbworld.org/forums/sl-class-...al-sticks.html
https://mbworld.org/forums/w218/4583...edal-feel.html
Anyone else encountered this issue?
Thanks!
Would like to have opinion from some experts here, like konigstiger seems to have access to a lot of documentation about these cars.
I don't know if the brake booster is a vacuum operation or electronic or both. Im thinking that the booster operates from a signal coming from the brake pedal, i.e. there would be a force sensor of some kind at the pedal linkage that gives a signal for the booster to take action. If this sensor gets "sticky" it takes more force for it to see the pedal force and this could be the reason why first pressing the pedal is felt like sticky pedal until force on the pedal is high enough to activate the booster.
If there is such a force sensor I don't understand why MB does not go fixing it as it could be just an adjustment on the sensitivity of the sensor...?
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Senior Member
Joined: Jul 2013
Posts: 261
Likes: 4
2010 MB 350i Coupe P2 WD
It maybe you are missing a vacuum on a cold start
looks like some vacuum leak in a brake system and
if it is the case the problem will get worse over time
it is a SAFETY issue , dealer should fix it ASAP
GL
looks like some vacuum leak in a brake system and
if it is the case the problem will get worse over time
it is a SAFETY issue , dealer should fix it ASAP
GL
Last edited by champaign777; Sep 6, 2013 at 12:03 PM.
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Thread Starter
Junior Member
Joined: Nov 2012
Posts: 46
Likes: 0
From: San Diego, CA
2012 E350
Took it to the dealer again ..... they still were not able to repro the issue.
What's the best way to test whether or not there is an issue with vacuum / brake system? If there was something wrong, would it show up in the error codes log?
Quite disheartening.
What's the best way to test whether or not there is an issue with vacuum / brake system? If there was something wrong, would it show up in the error codes log?
Quite disheartening.
Last edited by Ajax Lesser; Sep 17, 2013 at 05:39 PM.
MBWorld Fanatic!
Joined: Nov 2001
Posts: 5,851
Likes: 196
From: Huntington Beach, Ca.
'17 Jaguar XF
If your booster is like mine the vacuum line attaches to one of two connectors on a plastic elbow. The other connector is plugged (maybe for a test/calibration connection?). Check those connections. Does it make any difference how long you wait before depressing the pedal after start?
Out Of Control!!
Joined: Jun 2004
Posts: 13,799
Likes: 3,228
2014 E63S; AMS 100 octane ECU dyno tune; EDOK TCU tune; BB intakes; sprintbooster
have a subtle, similar issues on my 2k14 .. not too worried about it, but will bring it up if it becomes more prevalent .. seems like an inherent "feature"
