All,

Just wanted to know what is involved and is it very hard to replace the Master Cylinder?  I have the original on it now and I think it is time to replace it. 

What makes you think it needs to be replaced? Is it leaking or some other problem making you think it's at fault? Unless you're sure it needs to be replaced, there's no advantage to doing so outside of aesthetics.

If it does need replacement, it's a very basic thing to do. Before starting, liberally spray all connections and bleeder valves on the calipers with penetrating fluid like WD-40 and let it sit, even overnight. No point in breaking off any bleeder valves by being too impatient. Remove the old master cylinder after disconecting the brake lines. Before installing the new master cylinder (just the reverse procedure), it should be bled of air on the bench. It should come with instructions on how to do that. After installing it and making sure its connections are secure, you need to bleed the brake lines at each caliper, starting from the right rear, then the left rear, the right front and ending with the left front. If you don't have a bleeding kit for one person use, you'll need a second person to depress the brake pedal when you bleed each caliper. All the second person does is pump the brake pedal and hold it down when you crack open each bleeder valve. You close the valve then go to the next caliper in line and repeat. Make sure you add sufficient fresh brake fluid (DOT 3) when done.

Not a big deal, unless you happen to snap off a bleeder valve, that's why you soak them ahead of time with penetrating fluid.