I have 1995 with ac problems start out driving it and will blow very cold then all of sudden it will start blowing out hot air, could it be the vacum on the system, I noticed a ball under hood that one of the lines is very brittle and broken.

Thanks

 

Not sure, but vacuum line is around $1.25/ft at Autozone. I'd fix the line regardless. You don't want to stall out and be 'up creek' at 3am.