I need some quick help~I am changing the brake pads and rotors on my 2003 c230k 4doors sports.

How do I press back in the piston?????
I'm using a c-clamp but it won't go in.??? I need some quick help I need it done before pm.Thanks

 

anyone??

 

See other post.

 

Im puttin on the pads and im trying to push in the piston but iut wont go in.any ideas?You didnt answer my quiestion

 

Cap off the master cylinder? And use the old pad to keep the cylinder straight, so it doesnt get stuck to one side? Clean the dirt from around the exposed cylinder so it doesn't damage the seals.

 

go to your local autoparts store and buy a brake-caliper opener. It goes in between the pistons, and then you turn a knob that will open up the pistons. You can use the old brake pads to help protect the pistons. It shouldn't be more than $10. Don't step on the brake pedals while your working on the brakes. Goodluck

 

PsiTerror: Did you have a B5 Passat before your Benz?

I just did my brakes a couple of weeks ago. There is some slight resistance to get the piston moving, but once it's moving it slides pretty freely.

First, make certain that the cap is off of the reservoir, and that there is enough room in the reservoir to accept the fluid that you are going to be pushing back (by compressing the piston).

Next, I put the old brake pads back in the caliper, and used a pry bar between the old pads to press the piston back (twisting the pry bar). At some point, you may need to add more spacer material (maybe the old pads from the other side), but eventually the piston will be fully compressed.

In case you're worried, there is no need for a special tool or technique (not required to turn the piston while compressing or anything like this), just find a way to push the piston in and you're fine.

 

I tryed using a c-clamp but the piston is so siezed the c clamp broke.
It won't go in at all.What can I do???

 

First thing that I'd do is put the rotors/calipers back on the car, and then pump the brakes a couple of times ( BE CERTAIN THAT THE ROTOR IS BETWEEN THE PADS - OR YOU CAN PUSH THE PISTON OUT OF THE CALIPER . . . THIS WOULD BE BAD). Maybe the piston's just wedged on an angle or something.

Then try to compress the piston again.

(No need to put the wheels back on, just mount the rotor/caliper, step on the brake a couple of times, dismount, and try again).

Give that a shot first, and let us know what happens.

 

I tryed that and I bought a new c clamp and it still will not go in wtf....

What else can it be??????

 

This is really odd. By chance were you using a cheap C clamp?

Wish I had some ides for you, but the most creative I can get is to loosen the bleed screw on the other axel's brake. For some reason, the pressure is locked on the line, and therefore not allowing the piston to move.

Hmm, this also makes me think about releasing the pressure on the bleed screw on the brake you are working on. Try these steps. Tell us what happens.

E

 

A couple of questions:

1) Were the brakes working normally before pulling the caliper? (not pulling to one side)
2) Are you able to reinstall the caliper using the original pads, and did it operate correctly?

If you've still go the car jacked up, you can try to reinstall the caliper/rotor, then mount the wheel. Attempt to spin the wheel while someone is applying the brakes. If the wheel spins freely, and then stops (not possible to turn wheel) when the brakes are applied, this would indicate that the piston is moving (a good sign).

If the wheel spins freely, and doesn't grab (when the brakes are applied), then the piston is frozen, and you've got two choices: rebuild the caliper or buy a new caliper complete.

Is it the front or the rear that's stuck?

 

I'm in agreement with the above. Let us know what happens. I'm getting ready to go out, if you need additional assistance, I can call a MB tech to see what he says, but in my opinion, brakes are brakes.

Please do give us the outcome.

E

 

Try opening the bleed port and drain into container as you try compressing.

 

I always thought that if you push the pistons apart w/ moderate effort and they dont move... that meant that you should bleed the brakes some so there would be less pressure and that excessive force could cuase seals in the brake system to break... bottom line, bleed the brakes some.

-j0hn

 

Given the brake system (seals/hoses) can handle the force that a person can generate with a leg press action, multiplied by the brake booster, you'll have a rather difficult time blowing a seal in the brake system.

I don't have the specs on the brake system, but most systems of this type would be good for several hundred PSI, if not thousands.

 

Egads! Another canted piston from using a C clamp to reset the caliper piston.

The piston may now have a nick in the side that will make it unusuable. Too bad. Calipers are expensive for what you get.

When pushing the piston back you can't use a tire iron, a huge screwdriver, or a C clamp from the 99 cent store. You need a parallel jaw piston resetting tool.

The brake fluid will flow backwards through the relief port in the master brake cylinder. If you have "topped off" the fluid for any reason, you must remove some fluid from the car before you reset the piston. It is a good idea to remove the top of the resevoir. The brake system is vented to the atmosphere through a wee hole in the cap. You don't want fluid squirting out of this hole on the underside of the hood. Brake fluid is one of the best paint solvents, and will instantly spoil the finish. The first time you do this have someone watch the fluid level whilst you slowly crank the piston back inside.

 

Don't know much about anything...but what I do know is I watch the guy changed my brakes last week and he simply used a big *** wrench and squeezed them. With much pressure, it slowly started to move. He did that on all 4 and I learned something last week. Glad to share.

 

Thanks everyone for there help.
I tried opening up the bleeder valve with no luck.After lots of attempts to get f%^^er in I removed the whole caliper and used this to push it back in.
It worked though

.

I put the top part into the piston and pushed it down and it went right in.I checked if there was anything damaged like the seal everything was fine.
I'm pretty sure it was my fault for not replacing the pads sooner.The piston was so far out the rotor and pads looked like this.


There's nothing left on the pad.

Here's the clamp




Nope but I did have a 20th anniversary GTI.

 

Great to hear that you were able to get it going!

(I do agree, I think that you used most of the 'good' off of those pads. . .)

 

C-Clamp is OK to use as long as you put the old pad over the piston to keep flat even pressure over the piston. On the Mustang forum one guy just used a c-clamp straight on the edge of the piston and warped it. Now he has a brand new caliper. Also, one way to get it started is before you remove anything, stick a screwdriver in the hole on top of the caliper to spread the pads, this makes it easier to remove the caliper.

Lastly, these cars have complex ABS mechanism. Pushing the piston back in without opening the bleeder screw will push the dirty contaminated brake fluid back into the ABS mechanism and is not a good idea. Do a proper brake job, get a brake bleader kit, cheap one, not the suction pump kind and open the bleeder screw and when you are done with installing the brakes, bleed it properly with one person pressing the brake pedal while another opens/closes the brake bleeder screw. The suctions pump used in bleeder kits can also damage the ABS system. It would be sad to save $100 labor on the pad replacement and then spend $1,000 to repair the ABS.

 

Also if anyone is curious. I bought a new brake wear sensor and when it was time to put it on it was the wrong one.The plug was different so what I did was used the old plug with the new sensor. I cut them and spliced them together and it worked.