Figure 11-22 Testing Motor Fields for Grounds Figure 11-23 No Load Test Hookup
11-45. BRUSH HOLDERS.
a. To test brush holders, touch one test probe to the brush plate and the other to each brush holder.
b. The test lamp should light when the grounded brush holders are touched and should not light when the
insulated brush holders are touched.
11-46. GEAR AND PINION HOUSING. Inspect the housing for cracks and bearings for excessive wear.
Remove rust, paint or grease from mounting surfaces.
11-47. BENDIX DRIVE. The Bendix Drive should be wiped clean with a dry cloth. The pinion should turn
smoothly in one direction and should lock in the other direction. Replace drive if it fails to check as above or if
the pinion teeth are excessively worn or damaged.
11-48. ASSEMBLY.
a. When assembling the starter motor, always use an arbor press and the proper bearing arbor for installing
graphitized bronze and roller bearings. The Bendix shaft should have a thin film of Lubriphte 777 or equivalent
on the Bendix portion of the shaft, end play should be .005 to .050 of an inch.
b. New brushes should be properly seated when installing by wrapping a strip of 00 sandpaper around the
commutator, with sanding side out, l-1/4 to 1-1/2 times maximum. Lower brushes on to sandpaper covered
commutator and turn the armature slowly in the direction of rotation. Dust should be blown out of the motor after
sanding.
376B
377
KNIFE
SWITCH
CARBON PILE
BATTERY
STARTING
MOTOR
GROUND
AMMETER
VOLTMETER
GROUND
TACHOMETER
PIPER AIRCRAFT
PA-28-161 CADET
AIRPLANE MAINTENANCE MANUAL
Issued: FEBRUARY. 28, 1989
ELECTRICAL SYSTEM
2D18
