300SD Rear brake rotor - need help - PeachParts Mercedes-Benz Forum

thorsen · #1 03-04-2006, 01:22 PM

I am trying to remove the rear brake rotors on my 1984 300SD. It doesn't look like they have ever been off. I was under the impression that if I removed the rear caliper, the rotor would slide off the hub. Is this correct? I'm getting ready to find the BFH - just wanted to make sure there wasn't a set screw that was hiding from me.

Thanks.

P.S - I backed the parking brake all the way off.

Hatterasguy · #2 03-04-2006, 01:27 PM

Their is a set screw on the "hat" section of the rotor. It should be facing you if you are sitting on the ground looking at the rotor. You will need a little allen wrench to remove it.
Here is a picture:

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1MB12FET61QX0ST8W6&year=1982&make=MB&model=300-SD-002&category=All&part=Brake+Disc+Set+Screw

thorsen · #3 03-04-2006, 01:29 PM

I see that on mine, except the screw doesn't have a head. No slot, no hex, no star, it's just completly flat.

Hatterasguy · #4 03-04-2006, 01:31 PM

Hmm strange. Well thats it it needs to come out, if you want to remove the disc.

Maybe it is rusted badly and the head is filled in?

thorsen · #5 03-04-2006, 01:32 PM

I guess we'll find out shortly. I'm replacing the rotors, so I'll just drill it out.

Thanks for your help.

Matt L · #6 03-04-2006, 01:40 PM

I've removed many mangled bolts by using a center punch, punching around the edge in the right (left) direction.

thorsen · #7 03-04-2006, 05:24 PM

I centerpunched and drilled for a good 5 minutes with a 1/8" bit and all I got was a little dimple. I'm off to buy some cobalt bits and give it another go tomorrow.

RUinNC · #8 03-04-2006, 06:03 PM

I pulled a pair of rotors off an '83 300SD yesterday, and the only problem I had was the control arm was too low, pulling on the park brake cable, applying the brake.
Where was this set screw supposed to be?...between a couple of the lug holes on the surface the rim mounts?
Richard

tenknots · #9 03-04-2006, 07:25 PM

I pulled off both rotors on my 300SD last week and there was no screw. Once the rotor was off it just needed a little persuasion - make sure the parking brake is not on.

Hatterasguy · #10 03-04-2006, 07:52 PM

You can see the hole that the screw goes into on the disc:
http://catalog.eautopartscatalog.com/mercedesshop/sophio/quote.jsp?clientid=catalog.mercedesshop&cookieid=1MB12FET61QX16JIHM&baseurl=http://catalog.peachparts.com/&partner=mercedesshop&year=1982&product=N1000-16605&application=000014926

Its the counter sunk hole. Maybe in the past whoever did the brake job neglected to replace the screw?

thorsen · #11 03-04-2006, 07:59 PM

Color me confused. The rear rotors on both sides refuse to come off, they both have what looks like a headless screw in between a set of lug holes. They both refuse to come off, even when the parking brake adjuster is screwed all the way in.

At this point, I'm a little reluctant to drill out the screw, because I don't think it is a screw. I think it may be a mounting lug to locate the rotor.

The odd thing is that the repair CD has no information in removing the rotor.

thorsen · #12 03-04-2006, 08:16 PM

It looks like I was trying to drill #70. I guess I need to clean the surface with a wire brush and look for #64.

Hatterasguy · #13 03-04-2006, 08:21 PM

I couldn't find any info on my CD either. Clean the rotor real well the screw has to be their?

deerefanatic · #14 03-04-2006, 08:37 PM

My back rotors had no set screw at all. In fact, wheel hub has no hole for one to even screw into. And yes, I'm from a farming background, so I know what to look for to find it if it was broken off.

From the factory, my car had NO SET SCREW on the back rotors. Just a big locating pin (which your are trying to drill out!

)

thorsen · #15 03-04-2006, 08:52 PM

Matt - Does your rotor have a hole for the set screw?