i have tried two master cylenders and they are doing the same the same thing

Quote: All Datsun 1000 coupes [Oct 1968 onward] & all Datsun 1200 coupes had dual circuit master cylinders from new. All other 1200 models got the dual circuit master cylinder from about mid '72, so finding twin piston M/C in a 1200 should not be unusual at all.

If a 1200 car is 'engineered' with an A15 engine instalation, I could hardly imagine that it would pass muster unless the brake system matched the donor vehicle as an absolute minimum, & this would have the B310 Sunny as a base reference in Australia. The B310 came with a dual circuit system as did just about every passenger car that was sold here from at least '73 as it was, by then, a legal requirement.

just going back over old ground
i think found my problem one of the rear wheel cylenders has seazed leaving my pedal hard as a rock