Brake Pad Inspection Rear
Lining Inspection
- Inspect the brake linings every 9656 km (6,000 mi)
and any time the wheels are removed (tire rotation, etc.). The preliminary
inspection can be made with a mirror and flashlight (1).
- Remove the wheels in order to measure the linings.
- Measure the linings with
the brake caliper installed. The outer lining on brake calipers is exposed
for easy inspection.
- Check the inner lining on brake calipers through the inspection
hole in the brake caliper housing.
- Replace the brake pad assemblies when the lining is worn to 1.6 mm
(0.063 in).
- Measure the linings at their thinnest point.
Brake linings should lightly contact
the brake rotor or have no more than 0.13 mm (0.005 in) clearance.
It is normal for the brakes to drag if the brakes were applied shortly
before checking the brake clearance.
| • | If the brake linings are more than 0.13 mm (0.005 in)
from the brake rotor, pump the brake pedal several times and recheck the
lining clearance. |
| • | If the lining clearance is still not within specifications,
check for unevenly worn surfaces on the brake rotor, brake linings, or brake
caliper pistons. New brake linings may have more clearance until they have
worn to match the brake rotor. |
| • | If the gap between either brake caliper piston face and the
brake pad is more than 1.8 mm (0.071 in), overhaul the brake
caliper. |
| • | Remove the brake caliper in order to inspect the brake lining
surface conditions. The brake linings must be free of grease and oil. |
| • | The brake linings should show at least 70 percent wear (2) over
the braking surface compared to a new lining (1) in order to indicate good
lining contact. |
Knock-back is a condition that occurs when a turning
brake rotor pushes the brake linings and brake caliper pistons farther into
the bores than normal. Excessive clearance results from the knock-back
and the driver will notice increased pedal travel with the next brake application.
Loose or worn suspension parts, especially the wheel bearings, can increase
knock-back. Refer to
Wheel Bearings Diagnosis
.
Brake Pad Inspection Front
Inspect the brake linings every 10 000 km (6,000 miles)
and any time the wheels are removed. Check the following:
| • |
Inspect the outer brake lining at each end of
the caliper. The highest rate of wear occurs at this point. |
| • | Check the inner brake lining thickness for premature wear. Some
inboard shoes and brake linings have a thermal layer against the shoe that
is integral to the lining. Do not confuse this extra layer with uneven inboard-outboard
brake lining wear. |
| • | Look down through the inspection hole on top of the caliper and
inspect the inner brake linings. Replace bonded brake shoe and lining assemblies
when the thickness of any lining is worn within 0.76 mm (0.030 in)
of the shoe. Replace riveted shoe and lining assemblies when the thickness
of any lining is worn within 0.76 mm (0.030 in) of any rivet
head. Always replace the disc brake shoe and lining assemblies as a complete
axle set. |
| • | Check the flatness of new or used brake linings. Place the inboard
and the outboard brake lining surfaces together. Check for a gap between the
brake lining surfaces. The gap should not exceed 0.13 mm (0.005 in)
at the middle of the lining surfaces. |
The outboard
brake shoe and lining assembly has a wear indicator that contacts the rotor
and makes noise when the lining needs replacement (2). This noise is a loud
scraping.
