platt-deutsch

Just replaced pads. Learned about the electric servo on the rear brakes the hard way.. &&^&%%$# thing pushed the caliper piston all the way out.. GRRRR . got it all back together and working.

1bad540

how do you prevent it?

ItalianJoe1

By using the service menu to retract the parking brake to service position.

MBS63AMG

Pull out the push/start button. Put the key in , turn to position 1, press down on the "call" button and while still holding it down press the "OK" button. Then you will see the menu pop up on the screen. Make sure you begin this process with the menu in the "trip" series.

ItalianJoe1

You can do it with the button in, press it without stepping on the brake 3 times, couple seconds in between. It will end up in pos 1.

Must be on the basic Odometer/trip screen.

MBS63AMG

Ahh, I'll have to try that. Thanks.

brentlev

I have a 2015 S550 and I bought factory rear brake pads today. I took the rears apart, but could not get the car to go into " change rear brake pad mode", so I pulled the start button off, and put the key in on the first click and tried to get into the menu but failed, so I pulled the parking brake lever out, and tore the pads out. However, I was unable to push the pistons back even with a proper tool. This lead me to think that the car will not allow the pistons to be compressed back into the calipers to allow for new thicker brake pads, UNLESS it is in change rear brake pad mode.

Any thoughts would be appreciated.

I am new on this forum so sorry if there is a thread I did not find which covers this.
thanks
Brent

ItalianJoe1

Correct, the pad replacement mode moves the adjusters all the way in so you can press the pistons back. Without putting it in workshop mode, you can't push the pistons in without damage. If you already removed the pads, make sure they are back in before you do anything, as if the parking brake actuates with them out it will blow the pistons out of the caliper.

brentlev

Maybe I am having a brain freeze but for the life of me I cannot get the menu to pop up so I can select brake pad replacement mode. I get in, pull off the start button, insert key and turn to first on position, click on the trip odometer to show trip and total miles, then press and hold the ANSWER PHONE button and immediately after press and hold the OK button, for FIVE seconds and then forever ......and nothing.

Its a US spec, 2015 S550, we picked it up in Nov 2015.

Any help would be appreciated. My wife thinks I do not know how to change brake pads and should let the Stealer do it. I've been doing things like this since 1976 but never with all these electronic hindrances. Thanks in advance.

BTW, we just LOVE this car. My daily is a 2012 BMW M3 coupe with a 6 speed which I enjoy a lot in the local mountains of LA, but this W222 is surprising in how well it does when pushed, obviously, considering its heft. Way to go Merc.

ItalianJoe1

That sounds like you are doing the process right, you do have the doors closed right? It's the same menu where you reset service reminders. There's plenty of youtube vids showing it, i'd guess you are either skipping a small step somewhere or not timing the button press right.

brentlev

After having a bit of trouble, I asked a local MBZ mechanic to clarify the procedure. He said I was doing everything right but maybe my timing was off.

When I tried it later, voila, it worked. The only thing I can think of is after hitting and holding the answer phone button, I immediately hit and held the OK button. I did it almost simultaneously.

With the car in pad replacement mode, it was a piece of cake, just like any other car I have done a million times before.

One comment. This is a leased car so I used the factory pads ($73 at local dealer + $8 for the single wear sensor on the passenger side). These pads come with new bolts with a bit of lock compound on them. I have heard people ask where to get bolts and did not understand why they would need new ones, but it Merc gives new bolts free with pads, there must be a reason.

This whole thing cost about $90 for the rear and about 45 minutes of work. The last time the dealer changed all 4 corners (pads only, no work on rotors) it cost $1000. What a scam.

Thanks to all in this forum to help lead me in the right direction.

Nice Ride

So did you do all 4? How many wear sensors? One for each wheel or just one for front and one for rear....
Thanks

brentlev

I did just the rears. A while back the Stealer did all 4 (wife did not mention to me until after).

Regarding sensors, the rear only has one. I THINK the fronts have a sensor on each side - but I do not know for sure.

ItalianJoe1

That blue locking compound is why the bolts are one-time use. It's a two-part epoxy basically, and once installed, it mixes and locks, and it can't do that again. So you need new bolts every time.

ItalianJoe1

2 total on an S class, one front, one rear. They are different.

MBS63AMG

Yes, and mine were on the right side only.

MikeAtLincoln

Can you give me the proceedure to use on 2018 S Class? I have an S450 and I cannot get the above process to work! Thanks in advance.

ItalianJoe1

You have the new wheel with the touch pads, so the process changed.


Follow this one, it's same basic setup, Ignition in position 1, doors closed, basic odometer screen showing. Press home button, then in 1.5 seconds (when the menu bar starts to come up). press the center selection button on the touchpad once. Should go into the workshop menu.

platt-deutsch

The Hood May have to be closed to get to the servicr menu.
The piston on the Sevo motor can be turned to retract it also. I carefully used a pair of channel lock pliers.