1975 hasn’t been started in about 8 years. I got her to turn over and start but the rotor, caliper and pads are rusted. So they need to be replaced or will driving clear the rust? Any suggestions would be appreciated. 

Roderick

Personally, before driving, I'd take things apart and make sure the calipers are free and working.  A light sanding or wire brushing of the rotors would also be on my list.  If the pads are less the 50% I'd replace them. 

Then once everything is put back together, suck as much of the old brake fluid as you can out of the master cylinder and do a complete flush of the system to get the old fluid out of the master cylinder, the lines and the calipers.  A solid brake pedal is a GOOD thing on these cars.

A lot of people put a great deal of effort on making these cars GO.  But IMHO more effort should be put into making them STOP...!!!

My 2 pennies worth.

Thanks Jim,

That sounds like a plan. I pretty much knew that’s what I should do, guess I just needed to hear out loud, lol.

I wouldn't worry about the rust on the rotors. The problem you may have though is the calipers may leak because of rust inside the piston bores. Fortunately there are suppliers of stainless steel line calipers that takes care of this problem. 

I think I would sacrifice the old pads cleaning up the rust off the rotors and then replace the pads and flush the whole system with new Dot 4 or 5.1 fluid.  That is assuming you don't have to rebuild/replace the calipers.

Greetings, My opinion is that this is gonna pull your hair out. ANY time you open the system on these cars you'll have a can of worms. They are solid mounted, and are a poor system. The pucks move, not the caliper. If they don't leak now, they will later if the bores are pitted or rusty. Check runout of rotors. If they are still riveted, and not undersize, don't take them off. Runout of more than 5 thousandths is gonna be a problem. Factory tolerance is less. DO get stainless lined calipers, and replace ALL soft lines. Make sure the hard lines are also in good shape. Check for vacuum leaks if power. In good shape they'll scare ya, but they'll stop ya. Do a good job the FIRST time, and you won't have to do it again. 

Doesn't the '75 use DOT 3 fluid?

Duntov Motors disagrees:

"The floating shoe feature is a safety, as well as performance advantage. Only 5 thousandths of an inch retraction (of the pad from the surface of the disk) equals an inch of pedal travel and 410 PSI of pedal pressure reserve. The C2-C3 brake system was designed to rely on that 410 PSI pedal reserve, which is not available unless the pad is floating on the surface of the disk.

Bottom Line: If your Corvette is a static display show car, O-ring calipers are a good option. If you drive your Corvette, stick with Duntov’s design. If you drive your car only once a month, just depress the brake pedal every couple of weeks, and your lip seals should be leak free for at least a decade."

More here

Personally for daily drivers, I prefer DOT5 because it is hygroscopic and a plus feature is that it will not strip your paint if you accidentally spill it on it.