Two problems related to ball joint have been reported for the 1999 Jeep Grand Cherokee. The most recently reported issues are listed below.
Within four years approximately 8,000-10,000 miles both front brake rotors had to be turned twice and then replaced. Also, both front calipers had to be replaced. This causes vehicle to vibrate and make a grinding noise when braking. Dealer and manufacturer were notified, and were unable to locate the cause. The brakes pulsated while driving. The dash vent did not work, and the air only worked through the defrost. The consumer stated the front end of the vehicle felt loose, the dealer discovered the ball joints needed to be replaced. The driver side rear quarter panel was loose.
Loud banging on the rear floorboards over any bumps. Dealer and manufacturer say it's a ball joint on the new design of the rear suspension. They currently don't know how to fix the problem.