I am having trouble finding parts for my 1970 datsun 1600 roadster. I need a rebuild kit for the front disc brake cylinders. Or maybe some advice on how to get the brake cylinder unfrozen. I have come across a strange predicament where the autoparts stores will not turn my discs because they say that according to their books my discs are to skinny and worn down already. I'm just hoping that they have the specs mixed up since it's a fairly rare car. Does anybody know the minimum thickness for the 1600???