Reline The Brakes; Important Information On Linings And Primary Shoe Locations - Meritor Heavy-Duty P Series Maintenance Manual

8 Maintenance
Adjust the brakes as frequently as necessary for correct operation.
Check for correct lining-to-drum clearance, push rod travel and
brake balance.

Reline the Brakes

CAUTION
Reline the brakes when the lining thickness is 0.25-inch
(6.3 mm) at the thinnest point. The rivets or bolts must not
touch the drum. Damage to components will result.
Meritor recommends that you replace the springs, rollers, camshaft
bushings and anchor pins at each reline.
Reline the brakes when the lining thickness is 0.25-inch (6.3 mm)
at the thinnest point.
Replace shoe retainer springs, check the drum, and perform a major
inspection when you reline the brakes.
Important Information on Linings and
Primary Shoe Locations
Use the Correct Lining Material
Use the lining material specified by the vehicle manufacturer. This
will help to ensure that the brakes perform correctly and meet
Department of Transportation (DOT) performance regulations.
Also note that the drums and linings on a front axle can be different
than drums and linings on a rear axle. Figure 8.2.
Figure 8.2
TANDEM AXLES
Both wheel ends of each axle must
have identical drums and lining.
Figure 8.2
20 Meritor Maintenance Manual MM-0440 (Issued 09-04)
Single Axles
Always reline both wheels of a single axle at the same time.
Always install the same type linings and drums on both wheels of a
single axle.
Tandem Axles
Always reline all four wheels of a tandem axle at the same time.
Always install the same type linings and drums on all four wheels of
a tandem axle.
Primary Shoe Locations
The first shoe past the camshaft in the direction of wheel rotation is
the primary shoe. Figure 8.3. The primary shoe can be either at the
top or bottom position, depending on the location of the camshaft.
If the camshaft is behind the axle, the top shoe is the primary shoe.
If the cam is in front of the axle, the bottom shoe is the primary
shoe.
Figure 8.3
FRONT AXLE
4000376a
RIGHT WHEEL ROTATION
WHEEL ROTATION
CAM BEHIND AXLE
LEFT WHEEL ROTATION
WHEEL ROTATION
CAM IN FRONT OF AXLE
Figure 8.3
WHEEL ROTATION
CAM IN FRONT OF AXLE
WHEEL ROTATION
CAM BEHIND AXLE
4000375a