Problem:

I chose this sunny day to bleed my brakes (I bought the car used a month ago and have been getting around to checking everything--the brake fluid looked bad). I borrowed a vacuum bleeder from a friend and it worked well--or so I thought. I finished up all the bleeder valves (three on each front and then one in the back), and when I turned the car on and pushed down the brake, the brake was squishy. I never let the reservoir go completely empty--or at least not at the back grommet, though I may have let the front part of the reservoir go empty. Wondering if there is any way to isolate where there might be air, or if there is something else I did wrong. I have a 91 volvo 240 with ABS. I went in order LR, RR, RF, LF.

This may be a stupid question but if I did need to drive it tomorrow, would it be a bad idea to drive it with the brakes squishy?

Thanks for the help.

Jimmy