Rear-end grind noise?

[KStew67F100]

I recently rebuilt my rear drum brakes with new springs, new shoes, and new drums. After the rebuild I noticed there was a slight grind noise at a certain point in the passenger side drum's revolution, but just thought it might be slightly catching since it was new metal. The sound pretty much went away after a couple miles. Yesterday, I got about 2 miles away from home from work and a similar, but much more noticeable sound started up. I have not had a chance to get under there and check the differential fluid status, but does anyone have any thoughts or similar experiences as to what the issue may be? On a side note it was raining that day, so could water have snuck up into the housing or axle and caused friction of some sort? The truck is a 67 F100 360 with the 9" rear end (3.25 gear ratio). Any help is appreciated!

[tac]

I always go back and check the last thing I did. Probably have something in the not right in the passenger side brakes.

[youngone]

Best to pull that drum off and have a look see. A spring might have come loose.

[rjewkes]

Also with drum of see if you can turn the axles and if you have a sound still.