1992 Cadillac Deville

I took my 1992 cadillac deville for a test drive because I got my new wheel cylinders yesterday. I bleed them yesterday. I took it out a few moinutes ago and the brakes did fine until I came back the brake pedal kept getting stuck to the floor. I glanced down and why temperature guage came on it was red. I went to shut the car off but I looked at it and it was gone. Iput it in the garage and it was smoking a little. I popped the hood and it was smoking where the master cylinder was. I figured it was where I spilled the brake fluid. I turned the key on the car and the E73 light was on. I keep getting that in my codes and I keep erasing it. What does this code mean and what do I need to do to fix it. Back to the brakes. I looked down at the left rear and fluid was all over the ground not sure what it is until I look at it. I am letting it cool down. Any suggestions for the code. Thanks.