126 front brake pads alone- calipers still have to come off? - PeachParts Mercedes-Benz Forum

bigblue · #1 08-17-2008, 06:07 PM

About to change the front pads alone on my 300SD. They are worn down to about 1/8" thickness and the indicator started coming on like it should

Rotors/bearings are still in good shape and I just planned on changing pads with a new set of PBR's I bought of Roy/Phil.

Do I need to remove the calipers or is it normal to just slip new pads in place once the pins are hammered out?

I understand that I'd still have to press the pistons back in (crowbar against rotor?) and removing it completely wouldn't be that big of a deal if I had to with a C-Clamp but I just wanted to know if that's expected/normal/ridiculous or if there is a shortcut. If it is to be done that way, is it hard to compress the flat spring behind the pins?

I searched around for the answer to this question but couldn't find exactly that.

bgkast · #2 08-17-2008, 06:12 PM

No. You can just push the pistons back in using a screwdriver as a lever.

Now you can help me:

Help needed from somebody with a 300SD

Brian Carlton · #3 08-17-2008, 06:25 PM

It's normal to leave the caliper in place.

The best technique is to force the pistons back into the bores with two screwdrivers.......one from either side.....so you don't jamb the pistons. This is done prior to removing the old pads.

After the old pads are removed, a wire brush should be used to thoroughly clean the cast iron slides where the pads ride. There are four surfaces on each side of the caliper for a total of eight. It takes a good 20 minutes to do this job properly.

Then, a very tiny amount of brake caliper grease (sold in packets at McParts) is put on each of the cleaned surfaces. The new pads will then slip right in and operate very smoothly.

toomany MBZ · #4 08-18-2008, 05:13 AM

I used channel locks to push back the pistons. Remove only one pad, with the cap off the master cylinder, push back the one piston, install new pad, repeat on the other pad. You may want to remove some fluid from the MC, (I did) as pushing back the piston will displace fluid, it has to go somewhere.
Good luck, and keep us posted.

vstech · #5 08-18-2008, 08:36 AM

Quote:

Originally Posted by Brian Carlton

It's normal to leave the caliper in place.

The best technique is to force the pistons back into the bores with two screwdrivers.......one from either side.....so you don't jamb the pistons. This is done prior to removing the old pads.

After the old pads are removed, a wire brush should be used to thoroughly clean the cast iron slides where the pads ride. There are four surfaces on each side of the caliper for a total of eight. It takes a good 20 minutes to do this job properly.

Then, a very tiny amount of brake caliper grease (sold in packets at McParts) is put on each of the cleaned surfaces. The new pads will then slip right in and operate very smoothly.

wow brian, you have a lot of faith in us. what's the difficulty level of simultaneously depressing both pistons?

bigblue · #6 08-18-2008, 11:25 AM

Thanks. That's exactly the answer I was hoping for. Are you referring to levering the screwdriver against the side or corner of the rotor?

vstech · #7 08-18-2008, 11:29 AM

you will get it when you see it, but I put the screwdriver in the center of the pad, and pried against the rotor/caliper to get the piston seated, clean up the rusty/grungy area with a sawzall blade and put in the new pad, then go to the other side.
only do one wheel at a time, so you know how to put the springs and pins back in... unless you have an ate on one side and a bendix on the other... then it gets fun. take pictures before you start if you don't think you will be able to remember how to put it back together.

ColLonewolf · #8 08-18-2008, 01:22 PM

So you guys do not turn the rotors when you change the pads?? Do they not squeal??

vstech · #9 08-18-2008, 01:25 PM

turning them is usually a bad thing.
if they are warped, or groovy or too thin I replace mine.
if the rotors are damaged, you do have to remove the calipers...

pawoSD · #10 08-18-2008, 02:11 PM

Quote:

Originally Posted by ColLonewolf

So you guys do not turn the rotors when you change the pads?? Do they not squeal??

You don't turn MB rotors, you toss them if they are warped or worn out. They'll generally last about two sets of pads....they're cheap so its not really a big issue.

I've got about 55k on my front rotors and am on my second set of pads.....I figure I should be able to get another 20-25k out of the remaining rotors/pads, then I'm going all new, with cross drilled zimmerman rotors and organic pads.

Hatterasguy · #11 08-18-2008, 02:21 PM

Sometimes you need to crack the bleed screw to get the pistons back far enough to get the new pads past the lip. Its tight but they will fit.

ColLonewolf · #12 08-18-2008, 02:40 PM

Good to know, thanks.

MPH · #13 08-18-2008, 03:08 PM

[quote=Hatterasguy;1942008]Sometimes you need to crack the bleed screw to get the pistons back far enough to get the new pads past the lip. By doing this, you also do not force the dirty fliud backward into the system.

Hatterasguy · #14 08-18-2008, 04:57 PM

Yeah I guess so, but I flush my brakes once a year so I'm not to concerned about that aspect.

Grab a quart of DOT 4 and do that after the pad change.

E150GT · #15 08-18-2008, 05:18 PM

I always pull the caliper just to see what condition they are in. It doesent take that much time anyway, but I suppose it would be a little less messy to leave em on.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode