W203E35

So I was telling a coworker that this weekend I am going to change my brakes. (I have changed brakes before and I read the DIY on them)

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?

mleskovar

Some rear pistons are retracted by turning them. Yes you would do major damage if you tried to force them with a clamp. I haven't seen your year's brakes but I bet they can be just pushed in with a clamp. Electronically?? No way. Be sure to bed in your new pads.

splinter

No clue about VW’s “electronic” brakes. Last one I worked on was a 2nd generation 16V GTI.

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.

W203E35

Thanks for the info guys.

johnand

+1. I absolutely agree with this method of retracting the pistons.

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.

Glyn M Ruck

Excellent advice - & don't push the pistons back any further than you have to as this can cause the pistons to over return & give you a low brake pedal.

C230 Sport Coup

The rear ones went in so easily, i used my fingers.
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.

Buellwinkle

The VW is probably way more sophisticated than what we have in the C. Even our 1998 Mustang has more sophisticated brakes, haha. What he's probably reffering to is the new high-tech brakes like they use on the E320/E350 and yes, you need to do those with a computer or you will damage them, or maybe even damage you in the process. But don't worry about the C-class, it's easy. Like any brake job, have a good 4# sledge hammer on the ready to remove rusted on rotors. And yes, always bleed the brakes with ABS, otherwise you could damage them and then the $100 you save on the brake job will seem like a distant memory.

W203E35

Here is an Update guys.

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

mleskovar

What bolts are you talking about? The ones that hold the wheels to the hubs? Top ones?


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.

Glyn M Ruck

You got lots of life left. Do your pads on the car have the proper shims behind them?

W203E35

The ones on the caliper themselves. The star/hex bolts that you see from the outside. The ones that your not suppose to remove on the caliper.

Glyn M Ruck

I must say when I look at your pics they appear to have

W203E35

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

Glyn M Ruck

You have probably glazed the pads - sorry - I thought you had spayed something in there. You have to stop that brake fluid leak. It looks like a piston D seal is leaking unless its from a union because the bolts are loose - can't see

Glyn M Ruck

Presume they are OEM pads? - the dust will tell you

W203E35

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

W203E35

OEM for sure. I would wash the car Sunday. Went to work Monday and when I looked at the wheels I said to myself "Did I forget to clean the wheels?"

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

alpinweiss

Actually, your friend is correct on the VW Passat brakes. The new series Passat (2006 and later) is equipped with a push-button parking brake. It electonically activates the rear pads, which grip the rear rotors via servo motors. The brakes also have a hill-holder feature.

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.

W203E35

Thanks for confirming this.

Guys next time your buddy with a Passat asks you to help him with a brake job be aware

LILBENZ230

Does that site ask you for your VIN so that the parts guy can verify that those will fit your car?

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.

W203E35

OMG thanks you man. WOW it is a lot less than the ones I got (82.50)

I appreciate your help.

Thanks Again

LILBENZ230

No problem. They are excellent to work with and go out of their way to make sure you get the correct part. That's been my experience, anyway. Post on this thread if they give you correct part numbers for C350 sport pads.. that way in case anyone else ever searches they can find it here. I suspect it may be the same part as the C230 sport.. but I don't know if they changed or not between 05-07. There's been a lot of debate whether or not the C230 has 13.6" front rotors or 12.8". To me, the 2006-2007 C230 brakes seem a little smaller than my 2005.. so maybe the C350 got the 13.6" rotors and the C230 went with 12.8"?

Anyway.. I was rambling. Hope that MB of Annapolis can work it out for you!

W203E35

I just got to work and brakes don't squeak anymore.

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.

mleskovar

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