[8695Beaters]

I think rear brakes account for about 20% of braking. Although with rear drums 10% may be about right. That may not sound like a lot, but remember if the front tirs are doing 100% of the work, then then they will be ovrewhelmed pretty easily.

How did you fix the parking brake (what was wrong with it)? If we know that it may be easier to pinpoin the problem. And how much of a difference in braking are we talking about here? 2 feet? 50 feet? Is the pedal pressure any different? Specifics are really important for fixing brakes.

I don't know if you can afford it, but now would be the time to get some rear discs. Start in a junkyard, get all the parts, and then replace the pads. That will help a lot. I think you will just need the rotors, calipers, hub, and maybe the proportioning valve. Easiest thing to do would be to find a shop manual online and compare the part numbers. Anything different needs to be swapped.