Brake master cylinder, dual system, with one reservoir?

[Recoil spring]

I recently had a burst rear steel brake line on my 1997 LSS, got home ok but the brake fluid reservoir was low. This happened as the car was originally from Minnesota and the road salt really rusted the undersides. As the car sat, most of the brake fluid drained out, yet there is some front braking of the car.

I know that in 1968 onward cars were required to have a dual master cylinder and metering valve. On those the master cylinder was cast iron with 2 bowls, if you lost hydraulics in one, the other part of the master cylinder would have fluid to activate the other axle. The older cars from the 50's only had one reservoir chamber, once you had a leak, you lost all your hydraulic braking. What confuses me is on my car is there is only one plastic reservoir, not divided, when this drains out, what is stopping the car?

Any info on this would be appreciated.

Thanks.

[Tech II]

You have what is called a diagonally split system.....

That means your lf and rr are fed from the same area of the m/c, while the rf and lr are fed from the other area(front or back).....this gives you a little better control when breaking......

Yes, if you live in an area like NE, that uses a lot of salt on it's roads, it does tend to rust out the brake and fuel lines.....On the "H" bodies, the first to usually go was the rear one, that crosses over to the other side....not a hard fix, just find a portion of the line that is in good condtion, cut the line, install a fitting, bubble flare the line, and then with a union, replace the rest with prefabbed brake lines(may take a few pieces with unions to match the length)....however, if you plan on keeping the car, you may be better off replacing them all, if they are all rusted....which they usually are....