Alright, this is the oddest thing I have yet experienced. Within the last month when it is raining, or the roads are wet, I get this thumping at low speed when braking. It starts at about 15 mph and continues til I stop. I only notice it on the drivers side. Again, this only happens when wet. No issues when dry.

As far as specs: 99XJ, 4.0, 242TC, 87500 miles, Lifted 3", stock wheels, 31" tires, brakes & rotors replaced 1k ago.