chilidip

So, I was able to take everything off and by the time it was to retract the caliper piston I noticed there was a slot only on one side of the piston.
Meaning that my caliper retracting tool would not be able grip the piston in order to retract. Some posters on here stated that they've used a C clamp in order to retract the piston.. but did not want to go that route and break anything.

Has anyone successfully changed their rear brake pads on a 2003 C class sedan? Any help would be appreciated.

TIA

Boom vang

there are extraction tools for fixed dual piston calipers if you want to leave the caliper on the car. Or you can use 2 C clamps and and slowly tighten each side in unison if you remove the caliper off the mounting bracket. Never use 1 clamp as it will push out the opposing piston!


If you ensure your clamp is centered (I use the old pads under the clamp) and slowly tighten it, you will not break anything. I have been using this method for years on both my benz front and rear and my TR6

My Haynes manual shows using 2 large screw drivers simultaneously but I am not a fan of that method

chilidip

Wow, a screw driver can generate enough force to push back the pistons. I dunno, I'm still a little reluctant to do the C-clamp method.

Boom vang

open the bleed valve then they will rocket in with the screw driver method! You will have to re-bleed of course

Not sure why the fear of the c-clamp method, these are heavy cast iron calipers that are designed to handle lots of forces

Xhale707

Autozone has a 7 dollar tool you can buy for your brake pad change.

Popo

+1

It works very well and and saved me about 20 minutes per wheel compared to the first time i tried to do it using the screwdriver and a small block of wood.

definitely worth the $7.

phister

did mine yesterday... I just used my vice grip c clamps and it didnt damage anything. Just put the old pad in and clamp it down to push the piston in. I've always done the clamp way on all my cars and never had any problems.

mskembo

I've always used a C-clamp, it's the way my daddy taught me! just make sure you use the old brake pad like Boom Vang said (to protect the piston), I also use a shop rag on the outside of the caliper to keep from scratching it up.

Xhale707

I used that tool and a small block of wood on the front ones =D

chilidip

Sorry, been in the UK for a few weeks. I'm going to re-try replacing the rear pads this weekend. I always thought that the REAR caliper pistons needed to be turned in order to retract.... no? Meaning that it was threaded.. so if you had to use some force it wouldn't budge.. or ruin the threads. Btw- these are the dual piston calipers.. one on each side.

When I used to work on my Hondas, the fronts could be retracted with a C-clamp, while rears needed to turned with a needlenose pliers or the block shaped tool on a ratchet.

chilidip

What does this tool look like? You're not referring to this are you?

Boom vang

That is because the rears on Honda's and other cars use the rear caliper also as the parking brake mechanism (which needs a mechanical mechanism in addition to the normal hydraulic function of the calipers). Our cars have a set of drum brakes that function independently from the rear calipers as the parking brake and thus the piston does not have to be turned in to be retracted to take on a new set of pads, they just have to be pushed in simultaneously

sknight

And this applies even for early w203's?

I was never a fan of screwing pistons back in and welcome it if the rears just need a c-clamp or the specific spreader type retractor.

johnand

Skynight, send me a PM with your VIN and I'll send you the MB WIS documents for replacing your rear brakes.

Glyn M Ruck

And guys - Just a word of warning. It seldom happens but is a pain when it does. DO NOT push the pistons back into the calipers any further than required to insert new pads or it can lead to caliper over return & a low pedal. Sometimes when you push back too far & then stamp on the brakes to bring everything back into contact with the rotor/disc - the D shaped seal on the pistons distorts due to stiction in the caliper bore instead of sliding down the bore. This leads to the piston over returning back into the caliper when you lift off the brakes & the D seal returns to shape with a resultant low pedal unless you pump the brakes to move enough fluid. Then the only fix apart from risking blowing out a piston by pumping the brakes with no pads is to strip the calipers - do a dry assembly - blow the pistons & pads with compressed air at high pressure to achieve proper contact with the rotor & then bleed the system.

A dealer messed up a friend's W204 the other day by pushing the pistons back too far & you could push the brake pedal to the floor. We told them what to do but they went to Benz SA saying that some fool from the MBWorld forum had suggested dry reassembly. MBSA informed them that that "fool" was correct & to get on with doing it.

Caliper over return has been a problem on & off since the first Dunlop disc brakes were fitted to the Mk II Jaguar - big problem in racing - and most Alfa owners have experienced it with Lockheed Bonaldi dual booster/dual system brakes. Unfortunately it can also happen on a Benz.

sknight

Lubing the pistons with some brake fluid- is that recommended due to the condition named above? It was an old remedy I used to use to preserve seals on older cars and make sure the seals didn't roll.

C230 Sport Coup

Interesting.
The rear caliper pistons move so easily I think I use my fingers.
But typically, yea I just use a screwdriver wedged in between the brake pad and the
rotor.
Do one side, then jam something in the one side to keep it from coming back out
and do the other side.

I always pushed the calipers back as far as they would go. But I am using my hand and
fingers, just push them not using a clamp. I could see with a clamp you might go overboard.

After I replace pads, yes the pedal goes to the floor the 1st time,
the pads seat and then everything seems fine.
You're telling me this is wrong?

Hmmm.....if something is screwed up I'm not aware, though
I do have a slight hissing sound by the brake pedal, it's been there a long time.

chilidip

Thanks for this. It is precisely the information I was looking for. I didn't even think about the differences in parking brakes... learn something every day. I searched around and I think this is the tool that I may purchase.

Glyn M Ruck

On the Benz these days they have a rubber dust shield that stops the fluid you apply from getting into the bore.

chilidip

Thanks everyone for your help! It took only 30 minutes to replace the rear pads on Saturday. Btw- I used this tool instead to retract the rear caliper pistons.

pickupjason

just did mine today.
I always use C-clamp for the front pads and on other cars.
I still use C-clamp and the old pads to push the pistons and I did it twice each side since there are two pistons each side. It took me about a hour. This is the first time I change the rear pads on my wife's c230 with 60k miles.

The interesting thing is the old pads (at the passenger side) DOES have the slot for the sensor, but we all know that there's no sensor for the rear pads, only front one. Anyway, the pads I got is without sensor slot and it's slightly smaller than that from OEM.

Jason

pickupjason

Had some issues with the new pads..
Wife told me that she could hear a rather loud clicking sounds every time she releases the brake while she backs the car out of garage. I tested the car and heard the sound but can't really tell where it came from. Have my wife helped to drive the car while I stand next to it and found out the sounds was from the metal clip that hold the brake in position and only makes the sound when we release the brake while we wants move backward. I took everything apart and lubricated the pin and clip(where it contacts the pin and pads) but still the same. so I ended up put the old pads back and the sounds are GONE!
As I mentioned, the new pads( Duralast Gold) from autozone is slightly smaller, both width and length. Will take the new pads back to autozone and see what they could do. I may either return it and get a duralast cmax or get the hardware kit and see if it takes care of the problem.

should I always replace the hardwares(pins and clips) when replacing the brake pads?

j_nolesfan

Ok, I've done brakes on Pontiac, Chevy, Nissan, and a couple others. I don't want to mess up these rear calipers and I'm unsure how to remove the retaining pin for the pads. I'm going to get a little better light and take a second look but it's not quite obvious to me. I expected to find an allen head on the back side of the retaining pin but nope. Not sure if I'm supposed to push it out by putting something into one end and forcing it or what. It may all click in my head when I look again. I was just confused when I didn't find what I expected to see. Anyone?

Outkasted24

I have a Brake related question for anyone that can help me.
I'm going to do my Pads and Discs next weekend.
This past week I had a message pop up on my dash read out that says something about "the pad sensor indicating low pads, See work shop"
Now when I replace my pads and discs, Will that message automatically go out?
I don't have to replace any sensors do I?
Have any of you seen this message on your own personal W230 or do you replace the pads before any signs like this?

Thanks in advance

Boom vang

if you are getting the message then you wore through the pad sensor. It is basically two wires imbedded in plastic and placed through a hole in the pads, when the pads wear low enough it eventually will wear through the plastic exposing the wires that gets bridged by the rotor completing the circuit and hence the warning. If it is not completely worn through you can re-use it but since it is only about $10 a better practice is to replace it