Séb,

Here's some very fast written details about brakes...(And I'm only talking rear cylinder here!)

1958-1964
B16A/B/and B18A models use #667166

1962-1964
B18D models use #671216

1965-1966-1967: (stay focused!)

B18A models use #671216

B18D models use #671216 UNTILL: 120 chassisno. 225049 and 130 chassisno. 216949

-so, in 1967:
B18D models use #670404 when 120/130 chassis's - #671216 when 220 chassis.

1968: (polish the screen!)

B18A - European market, 130 chassis - #670404
B18A - European market, 220 chassis - #671216

B18B - European market, same deal! ok!? (#670404 and #671216)

B18B - US/Canada market, 130 chassis - #667166
B18B - US/Canada market, 220 chassis - #673391

1969-1970

B20A/B - European market (only) - #673731

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Some specs/expl.:
Chassis 120 - 4 doors
Chassis 130 - 2 doors
Chassis 220 - wagon
#670404 - 7/8" diameter
#671216 - 1" diameter
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So! - this is why it can be a little "dangerous" to talk brakesystem cross markets and years..

When! - all this is said - (and all this from a factory original point of view!) - Today it is normal to recommend the use of #670404 -because this is the small diameter (7/8") instead of the #671216 - Why? -because the asbestos has ben removed from brakepads and todays brakepads in the Amazon often tend to have a side effect of blocking rear wheels (Which is NOT fun)when braking hard.

Todays brakepads (front and back) require some more pedal-power than ancient asbestos ones and therefor the brakesystem in generel is a little more stressed and the true advise is then to use the somewhat little smaller cylinder for the rear brakes.

If you or any others have further questions, please feel free!
--
/Soren