what type of brake fluid do I need for a 1991 saab 900 convertible turbo?
I wouldn't want to steer you wrong, if you don't have the owners manual that came with the vehicle, when you go to purchase it the auto parts store will have the specific DOT# or you can contact a saab dealer. My best guess would be Prestone synthetic DOT4 which can be used for either 3 or 4.
most cars have the dot # stamped on the cap of the brake fluid reservoir of the vehicle, so take the cap off and read on it.
you can ad DOT 4 as well but not DOT 5