Brake Job Scare
My co worker told me something interesting. He has a VW Passat and when he was changing his breaks he pushed the piston back with a clamp (so it can go in and I have always done this too on my previous cars). Here is what was interesting, he said when he pushed the pistons back with the clamp that he broke the mechanism. From what he told me on with VW they move the piston electronically. (With a computer)
Now our w203s dont have this kind of option do they? I mean what would be the purpose of doing that? So people can take it to the dealer?
I can push the piston back in it's place?
Thanks
Electronically moving the piston back to it's place?

You will, of course, need to retract the calipers’ pistons to accommodate the new pads. Instead of forcing the system’s most degraded hydraulic medium back into the lines toward the ASR/ABS unit and master cylinder, I open the bleeder valves to remove the spent fluid. It’s also much easier to retract the pistons by doing so. Top up the reservoir with an approved 331.0 DOT 4 plus fluid, then flush and bleed the system using your preferred method. Inevitably feels and works better with fresh fluid and pads. Ensure you have a solid pedal before setting off on your test drive.
MB brake maintenance is a relatively simple task for the conscientious weekend mechanic.
However, the importance of doing it correctly – in its entirety - cannot be overstated.
You will, of course, need to retract the calipers’ pistons to accommodate the new pads. Instead of forcing the system’s most degraded hydraulic medium back into the lines toward the ASR/ABS unit and master cylinder, I open the bleeder valves to remove the spent fluid. It’s also much easier to retract the pistons by doing so. Top up the reservoir with an approved 331.0 DOT 4 plus fluid, then flush and bleed the system using your preferred method. Inevitably feels and works better with fresh fluid and pads. Ensure you have a solid pedal before setting off on your test drive.
MB brake maintenance is a relatively simple task for the conscientious weekend mechanic.
However, the importance of doing it correctly – in its entirety - cannot be overstated.
As far as the VW pistons, mleskovar is spot on. I bet your buddy was working on the rear calipers of a VW. They have a ratcheting mechanism in them, as they also do double duty as a parking brake (As do many other makes of cars). To retract the pistons they need to be rotated and pressed in at the same time. They make special tools that do it automatically, but I have easily done numerous of these style calipers with a pair of needle nose pliers.

You will, of course, need to retract the calipers’ pistons to accommodate the new pads. Instead of forcing the system’s most degraded hydraulic medium back into the lines toward the ASR/ABS unit and master cylinder, I open the bleeder valves to remove the spent fluid. It’s also much easier to retract the pistons by doing so. Top up the reservoir with an approved 331.0 DOT 4 plus fluid, then flush and bleed the system using your preferred method. Inevitably feels and works better with fresh fluid and pads. Ensure you have a solid pedal before setting off on your test drive.
MB brake maintenance is a relatively simple task for the conscientious weekend mechanic.
However, the importance of doing it correctly – in its entirety - cannot be overstated.




The fronts, I use a huge set of channel locks with tape on the teeth so as not to scratch,
and the old pads to push against the pistons.
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A problem has emerged.
I took off the tire only to see that the brakes did not match.
I bought them from MercedesGenuineParts.com

I noticed the Hex bolt was loose. I don't know how in the world this has happened.

Did some idiots try to mess with my car? It was only the top ones. Maybe they tried to steal them? Who knows.

My original Brakes have these holes where these pins go though them. Not the ones I got.


My only conclusion would be that I got the Luxury ones and not the Sport ones

But on their site they dont have a place to specify Sport so does this mean I should get the C230 ones?

Here is the one I got. Hopefully I can ship it back to them and they can get me the correct ones without a hassle.
I got a couple of questions:
Why would my brakes squeak? It seems like there is enough pad on there doesn't it?
Thanks guys
Last edited by W203E35; Apr 19, 2009 at 07:30 PM.
For one thing, you do not need new pads, there's plenty of wear left in them. The brakes squeal because the pads are vibrating. High temp grease (like ceramic) liberally applied to the pistons where they contact the back of the pads often stops the noise. Breaking new pads in properly also reduces the chance of them squealing.
Ya, they looked fine like the way they should be. Except the bolts on the outer side of the caliper was loose and I noticed there was a little brake fluid. (in the picture you can see brake fluid on the caliper)
Maybe brake fluid got on the rotor? I don't know who in the world would have loosen the bolts on the caliper.
The car has 24,XXX miles from your opinion do you think these brakes were changed before? Maybe wherever the previous owner took it for a brake job they loosened the caliper bolts on the outside?
I still don't know why they would be squeaking so much. It's almost mid way.
At first no squeak then slightly more they squeak and why I press the brake a little harder they stop. But they are pretty loud.
Thanks


The red are the bolts that were loose on the caliper.
The blue is where I saw there was a leak.
I tightened the bolts and the leaking had stopped.
Is there a seal that broke off that I have to worry about?
I just hope I don't come across any more problems down the line.
Thanks

Hopefully no more leaks. I can drive it a little more and if it keeps squeaking then I will try to put some brake grease then drive a little more until it's really time to change them.
Still got to exchange the brakes and get MB approved Brake Fluid. (Thanks splinter - approved 331.0 DOT 4 plus fluid)
Thanks Everyone for your help
My co worker told me something interesting. He has a VW Passat and when he was changing his breaks he pushed the piston back with a clamp (so it can go in and I have always done this too on my previous cars). Here is what was interesting, he said when he pushed the pistons back with the clamp that he broke the mechanism. From what he told me on with VW they move the piston electronically. (With a computer)
Now our w203s dont have this kind of option do they? I mean what would be the purpose of doing that? So people can take it to the dealer?
I can push the piston back in it's place?
Thanks
Electronically moving the piston back to it's place?

Although the system is somewhat complicated, it normally works well. The disadvantage is when it comes time for brake replacement. The rear brakes must be retracted via a computer, connected to the car through the OBD-2 port. The procedure is not complicated, just a bit unconventional.
Do-it-yourselfers must buy, or have access to, the proper software package and a computer. It works well on VW, Porsche, Audi, SEAT, and Skoda. It partially works on Mercedes and BMW.
Although the system is somewhat complicated, it normally works well. The disadvantage is when it comes time for brake replacement. The rear brakes must be retracted via a computer, connected to the car through the OBD-2 port. The procedure is not complicated, just a bit unconventional.
Do-it-yourselfers must buy, or have access to, the proper software package and a computer. It works well on VW, Porsche, Audi, SEAT, and Skoda. It partially works on Mercedes and BMW.

Guys next time your buddy with a Passat asks you to help him with a brake job be aware
I recommend www.getmercedesparts.com - it's operated by Mercedes of Annapolis, MD.
http://www.trademotion.com/partlocat...layCatalogid=0
They have the same pads for $69 instead of that $82.50.. and they will verify for you that you are getting the correct part using your VIN.
I recommend www.getmercedesparts.com - it's operated by Mercedes of Annapolis, MD.
http://www.trademotion.com/partlocat...layCatalogid=0
They have the same pads for $69 instead of that $82.50.. and they will verify for you that you are getting the correct part using your VIN.
I appreciate your help.
Thanks Again
Anyway.. I was rambling. Hope that MB of Annapolis can work it out for you!
OK, here is a scenario that made my brakes stop squeaking.
Very hard brake on a highway (pacific coast) to avoid hitting a box in the middle of the road. Windows down I did not hear a squeak. After that insane hard brake my squeaking stopped completely.




Learn something new every day. Leave it to the Germans to take something simple and engineer it to complexity.