I have problem that I need help with.

I have a 70 Mustang sportsroof that I am trying to bring back to life. I have it running, steering, shifting and stopping. The problem that I am having is in the rear end (somewhere).

I have only driven up and down the driveway. At the same spot when I back up there is a feel and sound that comes from the back end. It almost feels and sounds like something is binding up and then releasing. It is bad enough that I can actually feel it in the drivers seat. I had my two neighbors watch while I backed up and pulled forward. One of them thinks it is in the rear end. The other thinks it is in the rear, passenger side wheel (he thinks that the rear, passenger side wheel actually moved when it happens).

Here is some additional information:

1. Rear end is out of another model of Ford. The tag is "WDZ-8(or B?)1(or I?) 9EB 3L00 8 875A". So it is an 8" posi out of ? Fairlane?
2. The parking brake cables are not connected to anything (they are both hanging down).
3. When I apply the brakes and come to a stop the car rocks back and forth a little.
4. I raised the rear end up and turned the rear tires in both directions. They were hard to turn. And in certain spots (every 3rd full turn or so) they were very very hard to turn. Both tires turned together in the same direction. There was no play in the driver side tire. There however was about 1 1/2" of play in the passenger side tire. What I mean by that is when I turned the tire it turned about 1 1/2" before the axle engaged and the drive shaft turned. And when I turned the driver side tire the axle would turn and the drive shaft would turn immediately but the passenger side tire would not turn until the driver side tire had turned about 1 1/2".
5. The drive shaft and rear U-joint seem to be solid with no movement in /out, up / down or side / side.
6. I took the wheels off. The brake drums don't match. They have the same width and height dimensions but the profile is different. The hole in the passenger side drum that the axle hub sticks thru is also 5/16" bigger in diameter that the hub. So even though the lug holes are correct (correct pattern), the hub hole is not and the drum is loose.
7. I took the brake drums off. The brake components seem to all be there and installed correctly. The brake shoe adjusting device on the passenger side was not competely slid into the indented slot on the brake shoe. I just simply slid it back into position.
8. When I pulled on the end of each axle they did not move in / out or seem loose.

I think that is all I know. If there is something else that would help someone figure out the problem, just let me know.

Thanks.  

Have you thought about jacking the rear end up and putting it on stands. Then putting it in gear while you can listen to the rear-end to isolate the cause?