Chevrolet 2007 Silverado 1500 Pickup Owner's Manual page 516

If you have rear drum brakes, they do not have
wear indicators, but if you ever hear a rear brake
rubbing noise, have the rear brake linings inspected
immediately. Rear brake drums should be removed
and inspected each time the tires are removed for
rotation or changing. Drum brakes have an
inspection hole to inspect lining wear during
scheduled maintenance. When you have the front
brake pads replaced, have the rear brakes
inspected, too.
Brake linings should always be replaced as
complete axle sets.
Brake Pedal Travel
See your dealer if the brake pedal does not return
to normal height, or if there is a rapid increase
in pedal travel. This could be a sign of brake
trouble.
Brake Adjustment
Every time you make a brake stop, your brakes
adjust for wear.
516
Replacing Brake System Parts
The braking system on a vehicle is complex. Its
many parts have to be of top quality and work well
together if the vehicle is to have really good
braking. Your vehicle was designed and tested with
top-quality GM brake parts. When you replace parts
of your braking system — for example, when your
brake linings wear down and you need new ones
put in — be sure you get new approved GM
replacement parts. If you do not, your brakes may
no longer work properly. For example, if someone
puts in brake linings that are wrong for your vehicle,
the balance between your front and rear brakes can
change — for the worse. The braking performance
you have come to expect can change in many other
ways if someone puts in the wrong replacement
brake parts.