earlier is not better but will fit without changing spindle (this is not from personal experience, i am repeating what i read above). later is larger diameter requiring new spindle and larger diameter wheels. early 126 vented rotors fit 123 chassis and you just bolt on the rotors and larger calipers. the pads are the same. i am not sure about the dust shields. i wouldnt have thought you would have to change that but some folks seem to have said you do.

cant help on non stock rotors.

tom w

i should go pull all the calipers and stuff off the w126's ive seen in the local salvage yard...

i did order slotted rotors for my W123 but worldpac sent me the ones for the W126.. no wonder they wouldnt fit(they were vented... not solid)

Ahhh, got it. No difference in diameter (278 mm) between 123 and early 126, but the gain is ventilated rotors from the 126 (22 vs 12.6 mm thick). Diameter goes to 300 mm when using late model 126s.

Do you have a worldpac wholesale account or did you go through a website like Phil's or Rusty's? I could only find the cross drilled ones at those sites. I'd guess slotted would work better than cross drilled for solid rotors, since hot gases and dust are trapped without the hollow center of a vented rotor.

bingo.

tom w

sounds like a good upgrade, my W123 coupe is running 116 450SE ventilated brakes, unfortunately my brake pedal has been spongy for quite some time now, i replaced the master cylinder and bled the brakes and its still the same, im going to change my brake booster next and hopefully its fixed and i can see how good the brakes really are.

I also heard that you can upgrade to the W126 brake booster and get a lot of extra braking power (I think it was claimed like 20%). Is this true?

that will decrease pedal pressure needed perhaps. but you surely can lock up your brakes as it is, so for me it wouldnt be worth any trouble to change.

tom w

Tom's right. You'll only have a "lighter" pedal. Check out stoptech.com. They have loads of information about what you want in a braking system. Its all about heat management.

Installed
 

I finished up the early model sonderklasse brake upgrade to my 1984 300D this week:) Here are some pics. I ended up buying Cardone rebuilt Ate calipers for a 1982 300SD because I didn't trust the junkyard found ones to not leak. These are Balo rotors and are very high quality. I didn't get the cross drilled rotors, since they were 2x the price and I was already upgrading using S-klasse. Pads are PBR ultimate ceramic. Hoses were replaced too. Bearings were repacked with 60g grease each with new seals and play set in with a dial gauge to specs. They look pretty sweet:D

Just a warning to those using Cardone rebuilt calipers...buy new bleed screws separately from the calipers (from Phil or Rusty) since the two pairs I've bought recently both had the bleed screws ubertorqued into the calipers which crushed the screw.

Cool, are the calipers already coated/painted?

yeah, looks very sharp!

tom w

When you install a new master cylinder, you must 'bench bleed' the master cylinder. This inolves using some tubing, connecting them to the brake ports and curving them around to empty into the brake fluid reservoir. Then, the pistons are moved in and out to prime the pistons with brake fluid. then, mount the master cylinder on the brake booster and connect the brake pipes.

Use a power brake bleeded and bleed the brakes.

I'll see if I can post some pictures of the procedure.

No matter what you do,
ALWAYS, ALWAYS, ALWAYS, use some sort of backing plate. Even a home made thing will be better than none at all. They are extremely important, for both cooling, and heavy debris. I'm basing this on a lot of years professional brake work experience. The reason these aftermarket companies tell you not to put them, is purely cosmetic. They believe it, "Dirties" their product. I'm interested in making this upgrade. I will get most of my parts from a private source. Please, though just make sure you put on backing plates on whatever you build. They are very effective for a long list of reasons, and I could not stress it more.

what do you mean backing plate?

a benz has them from the factory.

tom w