Whats the difference between first and second gen W126 brakes?
 

Anyone?

One generation!

For the sedans, the rear brakes remained the same throughout the entire production run of the 126. The front brakes, however, were enlarged on the 2nd generation cars from 14" to 15" (278 to 300mm) rotors with correspondingly larger calipers and (inner) dust shields.

For the SEC the picture is a little more complicated. The constants here are that the rear rotors were always the same as on other 126s, and the later SECs have the same braking system, front and rear, as the later sedans. But there were several peculiarities to the early coupes. The most important of these is single-piston floating calipers on the front instead of the familiar dual-piston fixed calipers. The early SEC rotor was already slightly larger than that of the early sedan, at 285mm. And the rear calipers are also slightly different on the early SECs.

You appear to be a 123 owner. If you're contemplating a brake upgrade, I have read that early 126 brakes are a direct bolt-on to the 123. While I personally can't vouch for that, I suggest you stay away from early SEC equipment as potential transplants.

What I am looking for is if the second generation is a bolt on as well. Looks like its time to play mix and match at the junk yard!

The posts I've read on this said that that 2nd generation w126 brakes need the spindle too. I'm not sure if that's true, but i stuck with the 1st generation since all I care about is having vented rotors. I got my w126 calipers from a 1985 300SD. I'm just waiting on the rotors and hoses to start the job.:cool:

Egh, that means new balljoints as well. That makes it a pricey upgrade. The spindle is not that big of a deal, a weekend at pull a part.

I'm doing the wheel bearing at the same time, since I'm pulling off the hub. What do you think about freezing the races and tapping them in yourself vs. taking them to a shop for R&R?

One thing to remember is you will need to go to 15" or bigger wheels. I THINK the rotors and calipers will bolt on, but I am not sure if you would need to change the master cylinder and so on. One good thing is that you can add ABS if you pull the entire system from a later car.