Yes you can get different pressures out of the master cylinder. I understand your query. Since the bore is the same, it would seem that output would be the same. The way you can get a pressure bias is through piston surface area. The rear most piston has a centered semi floating rod that deducts from the overall surface area of that piston. The second piston has no rod, or less of a rod. More surface area= less pressure.
If the bore is the same for both piston cups there will be no difference. A rod pushes the rear cup and fluid pressure alone pushes the from cup to make up for clearance issues. Has anyone ever taken one of these apart to see how they work?! Or is this something you read off the net.
