So now that I have replaced thw master cylinder in my car I am left with a couple questions. First how can I tell if the master cylinder I took out is original to the car, I suspect that it is. Also I bled the brakes, 4 wheel drums, in the proper order and now have a very hard but what I think is a low pedal. Would adjusting the brakes be the next step? One last item the flexible brake lines to the front drums can they go bad on the inside?

 

either u didn't adjust the rod lentht rightand yes the the rubber hoses collespe over time

 

Absolutely. They can rot from the inside out. If they're old, replace them. With regard to MC, why does it matter? The thing wore out, now it's been replaced. If it turns out to be really important, just search the interwebs for underhood pictures of your car. Try Google images for starters.

 

There should be a 2 letter stamp on the MC which is set forth in the assembly manual I believe. If it has bleeders, i's more likely to be original, and folks do look for those.

 

Here are a couple of photo examples of original master cylinders for reference. The "CT" is a drum master correct for all cars from 68-72. The "EB" master is correct for all disc brake Olds in 1970. hope this helps.

 

Thanks for the info, it is not the original master cylinder, I adjusted the rod on the booster and adjusted the brakes, is much better now. Will be replacing the rubber brake lines this weekend.