Rear Disc Brake Rotor; Inspection; Refinishing Brake Rotors - Isuzu Trooper 1999 Workshop Manual

Inspection

In the manufacturing of the brake rotor, all the tolerances
regarding surface finish, parallelism and lateral runout are
held very closely. Maintaining these tolerances provides
the surface necessary to assure smooth brake operation.
Lateral Runout
Lateral runout is the movement of the rotor from side to
side as it rotates on the spindle. This could also be
referred to as "rotor wobble".
This movement causes the piston to be knocked back into
its bore. This results in additional pedal travel and a
vibration during braking.
Checking Lateral Runout
1. Adjust the wheel bearing correctly, refer to
"Differential" in Section 4A.
2. Attach a dial indicator to some portion of the
suspension so that the stem contacts the rotor face
about 29 mm (1.14 in) from the rotor edge.
3. Move the rotor one complete rotation.
1. The lateral runout should not exceed 0.13 mm
(0.005 in)
Maximum runout: 0.13 mm (0.005 in)
Parallelism
Parallelism is the measurement of thickness of the rotor
at four or more points around the circumference of the
rotor. All measurements must be made 22 mm (0.87 in)
from the edge of the rotor.
POWER ASSISTED BRAKE SYSTEM

Rear Disc Brake Rotor

The rotor thickness must not vary more than 0.010 mm
(0.0004 in) from point to point.
Maximum parallelism: 0.001 mm (0.0004 in)
Replacing Brake Rotors
When installing new brake rotors, do not refinish the
surfaces. These parts are at the correct level of surface
finish.

Refinishing Brake Rotors

Accurate control of the rotor tolerances is necessary for
proper performance of the disc brakes. Machining of the
rotor should be done only with precision equipment. All
brake rotors have a minimum thickness dimension cast
into them.
dimension and not a refinish dimension. The minimum
wear dimension is 16.6 mm (0.654 in). The minimum
refinish dimension is 16.97 mm (0.668 in).
When refinishing rotors, always use sharp cutting tools or
bits. Dull or worn tools leave a poor surface finish which
will
dampening attachments should always be used when
refinishing
eliminate tool chatter and will result in better surface
411RS019
finish.
This dimension is the minimum wear
affect initial braking
braking surfaces.
5C–47
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performance. Vibration
These attachments