R & R for Rear Brake Disc for 560 SEL - PeachParts Mercedes-Benz Forum

cherry_560SEL · #1 03-03-2010, 09:06 PM

Does anyone have the PDF page 42-0228 from the W126 Maintanance disc? I cannot get these disc brakes off !!! I have pounded on them with a rubber mallot and still nothing

Hirnbeiss · #2 03-03-2010, 09:22 PM

Are the parking brake shoes fully retracted? Sometimes you need to turn the star adjuster (through the access hole, with a screwdriver) to retract them enough for the rotor to come off.

cherry_560SEL · #3 03-03-2010, 09:25 PM

hmmm....haven't tried that yet. Is that little star adjuster visible with the disc on?

tinypanzer · #4 03-03-2010, 10:14 PM

If it's like most others I've worked on, it's on the back side. Theres usually a little hole that you stick a screwdriver into and back off the adjuster screw. Then the shoes will retract enough to get past the lip they have cut for themselves. Shouldn't be too much of a lip unless somebody's been driving with the e-brake on.......

Hirnbeiss · #5 03-04-2010, 06:18 AM

But the rotors are often a PITA anyway. Let penetrating oil soak in around the hub. I have also used a 3-jaw puller to apply constant tension and the rotors have popped off by themselves after the oil has soaked in. Many people also use the total brute force method of a sledge. I'm assuming also that you remembered to remove the 5mm hex retaining screw.
The star will be at around 11 oclock on the passenger side, and you need a good flashlight to see it (http://www.peachparts.com/Wikka/W126RearBrakes picture 7 shows the adjuster between the brake shoes)
See also:

Wodnek · #6 03-04-2010, 07:07 PM

A 3 or 4 lb sledge hammer is pretty much what you need. Alternate between pounding sideways on the hub, front side of the disc and back side of the disc. It will come off.

A rubber mallet just wont do it.

cherry_560SEL · #7 03-07-2010, 06:45 AM

OK...So I finally got fed up with trying to hammer the freakin' thing

!!!! I never thought that was a good idea to begin with but I was willing to try it. The whole notion that the parking brake could possibly make a groove on the inside is highly unlikely. Even driving with the parking brake on would not cause a groove to be made on the inside. I would like to see a picture of the inside of a rotor that this has happened to. Anyhoo, I took a three prong puller, attached it to the rotor and it came off with a very loud and surprising POP !!!! I nearly spilled my beer

. So, I now have some brand spankin new brembo rotors on the rear axle

....yes I changed the pads just to be safe. I do not have a dial test indicator so I am hoping the rotors are true to spec. Here's the weird part: The rotor on the passenger side came off without a hitch, so why the tight fit on the drivers side rotor

Also, once I pulled the old rotor off and placed the new rotor on, I forgot to clean the spindle and when I tried to remove the NEW rotor ...it was stuck

....it took a little effort to get it off. Anyone have an idea as to why that is ??? well....now I need to get the backseat off, which is supposed to be easy, but I can't figure it out yet...

Hirnbeiss · #8 03-07-2010, 07:46 AM

a good idea is to sand/emery the spindle and smear a thin layer of grease (I use dielectric grease, but don't ask me why) on it.

mramay · #9 03-07-2010, 10:31 AM

The parking brakes MUST be retracted before the rotor will come off easily. The adjustment is (IIRC) at about the 10 o'clock position and is accessed through any bolt hole on the front of the hub. My normal method is to turn it all the way one direction and if it didn't lock up the wheel (adjusted the brakes to the drum) then the rotor will come off. Since my luck is directed by Murphy's Law, I generally go the wrong way (tight) then have to turn the adjusting star the other way.

Smack the hub (not the rotor) with a steel hammer a couple of times to get the rotor loose, then walk it off. I find it comes off easier if I'm rotating the hub as I pull.

When it goes back on, adjust the parking brake all the way to tight, then back it off just a little.