Brake Proportioning

Hello all. With the recent snow I've come to notice that the brakes on my 80 volare are all out of wack. I have a manual brake system and the rear brakes are clearly catching before the front brakes and above all else the right rear brake catches first out of all of them. Isn't there a way to play with my brake proportioning valves both at the master cylinder and at my rear to get them to where they're supposed to be? If there is how can I tell if I got it right? Please help!
Author: Rifleshooter