* Consult a repair manual: A Haynes or Chilton manual specific to your 1988 Chevy Suburban will have detailed diagrams showing the brake system and the size of the lines used.
* Check your existing lines: If you can safely access some of the lines, measure them with a caliper to determine the exact diameter. Be extremely cautious when working with brake lines, as they are under pressure and contain fluid that can be hazardous.
Don't rely solely on general information when dealing with braking systems; accuracy is crucial for safety.
