Meritor MM-2075 Maintenance Manual page 22

7 Rotor
Measure the Rotor Thickness
CAUTION
Replace the rotor if it reaches the minimum allowable rotor
thickness found on the rotor casting. Damage to components
can result.
1. Use a micrometer to measure rotor thickness. Figure 7.7.
THICKNESS MEASUREMENT
Figure 7.7
2. If the rotor thickness is equal to or less than the rotor discard
dimension, then the rotor should be replaced.
Rotor discard dimension
- 70 mm Quadraulic: New rotor thickness 39 mm
Minimum allowable thickness 36.05 mm
- 64 mm Quadraulic: New rotor thickness 39 mm
Minimum allowable thickness 36.05 mm
- 64 mm Quadraulic lite: New rotor thickness 36 mm
Minimum allowable thickness 32.90 mm
3. If the brake rotor thickness is greater than the minimum
allowable thickness and the user would like to continue
using the current rotor, then the user should evaluate if the
remaining rotor thickness is sufficient to reach the next
scheduled service.
MM-2075 / Revised 09-23
Page 18
MINIMUM THICKNESS
FOUND ON ROTOR
CASTING
VENTED ROTOR
MICROMETER
4005054a
Copyright Meritor, Inc., 2023
Measure the Rotor Runout
1. Attach a dial indicator to the caliper or axle frame.
2. Check the rotor while assembled to the hub or spoke wheel
and mounted on the axle spindle. The lateral runout of the
rotor friction surface should not exceed 0.015-inch (0.381
mm) total indicator reading (TIR). The thickness variation of
the rotor should not exceed 0.0012-inch (0.0300 mm).
If the lateral runout or the thickness variation exceeds
the above values: Resurface or replace the rotor.
If it is necessary to service the rotor, hub, hub seal or
bearing: Remove the caliper according to the procedure in
this section.
3. Remove the hub and rotor assembly according to the vehicle
manufacturer's recommendations.
(16579)
Printed in USA