1970 280SL Brake master cylinder swap question

[h100vw]

Hi Chaps, I have the task of swapping the master cylinder out for a friend. The new one has 2 rubber inserts to take the reservoir. However, the original, I am guessing, doesn't.

Of course it's friday and I cant get the supplier of the new MC and ask what's happening.

Have we got the wrong part?

Pics attached for the original.

The replacement is ATE 03.2123-1003.3

Thanks in advance for any ideas or advice

Gavin

[h100vw]

Ok, so I am that guy.....

I have never been around the back of this car until just now... It's a 230, so that is going to explain a lot isn't it

Easier/cheaper to fit the 280 reservoir or beg the parts people to swap the MC?

[Benz Dr.]

Not exactly the right answer, but I have all of the original booster and MC on my 230SL. I put a disc brake rear axle in my car a number of years ago and it has excellent brakes. My point is that you can apparently mix and match certain parts in the system if you know what to do.
The 230 MC has a check valve on it for the rear brake line. It maintains a bit of residual pressure so that braking is sharp when you press your brake pedal and I believe the 280 MC doesn't use that part.

Best to use the 230 MC on a 230SL though.

[MikeSimon]

How about the in-line brake modulator. Do all W113s have taht?

[Benz Dr.]

How about the in-line brake modulator. Do all W113s have taht?

That's for cars with rear disc brakes. Prevents them from locking up under hard breaking.

[h100vw]

Thanks for the insider knowledge Benz Dr. I'm going to plead stupid with the supplying shop and see if I can exchange it for the correct one.