here is WIS procedure for rear brakes

https://mbworld.org/forums/5868689-post55.html

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I am considering replacing my rotors, thanks to you all here, I am confident its no more sweat than on other vehicles (save the Star bolt warning! Thanks!!)

Call me cheap or call me hesitant to undo anything that doesn't need to be, out of caution that it may break the first time doing it, but if I replace the pads before they are worn down, or I reuse the existing pads if there is lot of pad left, do I need to replace the wear sensor?

I know you have to once they go off, but are they continuous wear or a single time switch?

Thanks --david

 

No. Can't imagine putting on new rotors using old pads though.

 

wear sensor is a one time switch. You can re-use it if it has not tripped yet.

 

I wonder if this is true. My indicator is on now but every time I've had the car in the shop they had it checked off as being ok (Brake Pads) even though the indicator was on this last time I took it in.

 

WOW, the indicator is ON and they check the breaks OK?


Typical example of service that does not do what they say they do. What else did they check and really did not do? Like did they change the oil when they say they did and also made you pay for it?


The sensor on the brake pad is in position that leaves a good amount of pad material for use when the sensor trips but when it does I would change the pads soonest.

 

Thanks Arrie, good to know.

 

Thanks MLeskovar,

I agree I can't imagine not changing pads at the same time, but was envisioning trying a couple brands to compare OEM vs others... at 90% pad left on new, I might experiment but not have 3 entire sets.
'cause I do stuff like that. I'll takes the brakes apart to clean or clear them... wierd, I know.

 

So my dealer called and said my rear brakes needed to be changed, "wear bar showed"

I declined the service from the dealership, going to look at an indy

I thought there were wear sensors? are they only on the front?

 

I agree with Arrie, Tom and others that this is a DIY job. It really is not difficult and can be done with a jack, jackstands and regular home tools. It may take up to two hours if you have to struggle, have one jack and two jack stands. Hell, I didn't even buy a special tool to open the calipers, I just used a gardening tool, the one that cuts the root -- it has a 10 in long, 1/4 in round, shaft with the correct 20 to 25 degree bend in it, just enough to lever the calipers apart enough to slide the new pads in.
Generally, unless warped or seriously abused, rotors should last at least 50-60k miles or longer. Every time you replace a rotor you must replace the pads at the same time, not the reverse and, as was said, if the sensor is not worn, it's fine to reuse. OE rotors for MB are Zimmerman rotors, however, any well made rotor that is the right OE size will work just fine or better.

 

The brakes on W211 used to squeal with a good 5mm left on the pads. Dealer told me there is also a message that appeared in the instrument cluster when wear was critical. I was too chicken to wait for it at the rate my rear brakes were wearing out (Every 17-20K miles).

Although I never changed the rotors, only pads on both front and back. Dealer said no need to touch the rotors unless warped.

 

I have a 2012 E350. I felt a slight vibration braking on the hwy from 120km two weeks ago. The vibration is through the steering wheel. Dropped by an aftermarket dealership and they said vibration through the wheel is usually warped rotors. They checked the pads with a flash light and told me I have meat left in the fronts and about 2 months in the back (no warning light on yet) I knew this since I had replaced my winters with the summers two weeks ago. The issues is that this vibration is a new thing and the pads are not worn and I have not been driving hard so how could the rotors (new last year when I bought the car 15k ago) be warped?

 

Going to drive the week and if vibration stays I am going to replace (they use German aftermarket rotors (not the Mercedes ones though) 150/rotor and 85 install per side front (470 front both sides) (400 rear both sides) 870 plus tax total rotors and pads. BTW I live outside Toronto.

 

That is a good prices for all rotors and pads. Just make sure they put new sensors on. Also I just got all 4 of my pads changed in February and I switched to Ceramic pads. I get almost no brake dust now. I'm not sure if that is a concern for you but it was a big problem in the past with my old pads. Good Luck

 

When the tire swaps were accomplished, if an air gun was used on the lugs, there might have been an un-even tightening of the lugs which is widely known to warp rotors in most any vehicle including 1 ton pickup trucks. Like most anything where several fasteners are involved with substantial torque, they must be tightened to proper spec in 3 stages. Very easy to do incorrectly. Of course, that may not apply to your specific situation.

 

funny you say this because today i actually went to take the caliper off and started undoing the star bolts and flupid started pissing out.. i quickly tightened them backup .. didnt lose much fluid but i ended up bleeding that caliper just incase it caused any air in the brake line..

could i of caused any damage by doing this ? or as long as i made sure i bled the system i am ok?

 

You're OK As long as the fluid is going out and doesn't drop below the air gap point in the reservoir no air should enter the system. You did right.