Master Cylinder Bore

Smaller bore is generally preferred, since an easier pedal. I agree w/ post 2. The geyser of fluid is an indication of air in the system, or soft rubber hoses that are ready to burst, so fix that first (if you see it). On my manual drum Valiant, I use an MC for a 95-99 Breeze/Stratus/Cirrus w/ ABS on a 2-4 bolt adapter plate ($30 ebay). MC is aluminum, 7/8"D bore, w/ the modern plastic reservoir that seals tight & has a low-level warning switch. But, many later MC's can be used w/ the adapter plate. Many here use one for a late 80's Dodge truck w/ manual brakes.