rear end clang

has a clanging noise in rear end by left rear wheel.   has 46,000 original miles.has never been out of Fresno since new, but sat for 25 years being driven a few miles each week. I drove it back and forth to work 11 miles each way for 2 years with no problems.  I have had the front end completely rebuilt.  Bushings are worn, but intact.  This just started after I moved to San Diego recently.  First sounded like I dropped something off rear end while driving.  Pulled over, looked, saw nothing, drove off.  About 100 miles later, the noise started again, with a rotation of forward motion.  Could it be the UJoint?  I have checked brakes, nothing, I pulled off the rear wheel where the main noise seems to be coming from, and brakes seem OK, I was wondering at first if it could be the emergency brake hanging up, but this noise is just too loud.  Only modifications to rear have been new full blown exhaust, and the smog and cat converter have been removed, as no longer required in California.  Even though I am a female, my Dad was a mechanic for years, this one has me stumped.  I am new to area of Carlsbad and don't .have a mechanic here