I can try to rationalize Japanese technology. All I can say is, I ran down to my 77 FJ40, looked and that's how it was. I've been driving mine like that for 3 years. I've never even seen/noticed that spring before. So, my guess is it helps bring the pedal all the way back so that it's not...
right side of the brake pedal. There's a pin connecting the pedal to the rod going through the firewall. It hooks around the head of the pin. Let me know if you need a pic.