One problem related to front seat belt has been reported for the 1999 Ford F-150. The most recently reported issues are listed below.
Seat belts do not retract quickly and completely when released, a weak retraction spring and the upper plastic locater yoke and the cloth seat exert too much friction. Both seat belts were replaced, however failed after one use, driver side was replaced again and failed, there is a recall, 00v348, however this is for 2001 models.