90 Accord: 80 amp Battery fuse keeps blowing

Make sure you are not reversing polarity of cables and check for positive cable insulation to make sure it's not grounding and creating short.

Polarity is correct, no problem with insulation.
I did have brakes, master cylinder and booster replaced by reputable dealer. The next day, the battery was dead. Jumped it and let it run, turned off engine and it started ok but 3 hrs later it was dead again. Replaced battery because I thought it wouldnt hold charge but sounds like it was being drained by a short. I connected the terminals to battery and blew the 80 amp battery fuse (correct polarity). How do I narrow down my search for the short? I do have a 12 tester with red and green light and a new 80 amp fuse.