You ran over a basketball now your Sable makes a random knock sound near the front driver wheel?
was any part of the NET attatchet to the BALL ? get it in the
air...go to a local brake shop offering free brake inspections and
take a peek while they check your brakes...be sure to get their
written repair order/report on the status of your brakes!!:) also a
manual will help with diagnosis and repair, and a shop manual
should be available at the local library in the reference section
for FREE, make copies of the right pages, good luck...:)