[puddleglum]

Originally Posted by stovie

Talking about hydraulics, I'm planning on using oxygen tanks to make a hydraulic regent braking system for my s10. I'm wanting to have one tank hold pressure and the other hold vacuum after braking, so that way one pushes while the other pulls to try getting more power from a lower pressure. I'd like to be able to cut them open, put a piston inside then weld them back up.

I don't want to be a killjoy but it sounds like you are trying to make a simple mod really complicated. You said before, you couldn't use a bigger vacuum bottle because of lack of space, but now you are going to build a hydraulic accumulator with an oxygen tank and plumb it in? Even if you ignore the liability of changing the design of the actual braking system, you are going to use just as much space and spend way more money than adding a bigger vacuum reservoir. Why not just fit two or three smaller vacuum bottles and tie them all together in parallel. (I know you said you don't have room for one big bottle.) It's only one tee and a extra check valve going in to the brake system that way. This is, after all, a safety mod not a fuel saving mod, at least not directly.