Piper PA-32R-301T SARATOGA S, Maintenance Manual

Page: 814 / 956

BRUSH HOLDERS.
1. To test brush holders, touch one test probe to the brush plate and the other to each brush holder.
2. The test lamp should light when the grounded brush holders are touched and should not light when the
insulated brush holders are touched.
GEAR AND PINION HOUSING.
Inspect housings for cracks and bearings for excessive wear. Remove rust, paint or grease from mounting
surfaces.
BENDIX DRIVE.
The Bendix Drive should be wiped clean with a dry cloth. The pinion should turn smoothly in one direc-
tion 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.
ASSEMBLY OF STARTING MOTOR.
1. When assembling the starting 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
Lubriplate #777 or equivalent on the Bendix portion of the shaft. End play should be .005 to .050 of an
inch.
2. New brushes should be properly seated when installing by wrapping a strip of 00 sandpaper around
the commutator (with the sanding side out) 1-1/4 to 1-1/2 times maximum. Drop brushes on sandpaper
covered commutator and turn the armature slowly in the direction of rotation. Dust should be blown
out of the motor after sanding.
– NOTE –
The spring tension is 32 to 40 ounces with new brushes. This
tension is measured with the scale hooked under the brush
spring near the brush and the reading is taken at right angles
to the line of force exerted by the brush spring.
3. Check the position of the pinion to be sure the unit will mesh properly with the flywheel ring gear. See
specifications for unit for correct dimensions. (Refer to Starting Motor Service Test Specifications.)
BENCH TEST.
1. After the starting motor is reassembled, it should be tested to see that the no-load current at a certain
voltage is within specifications as given in Starting Motor Service Test Specifications. To make this
test, connect as shown in Figure 5. If current is too high, check the bearing alignment and end play to
make sure there is no binding or interference. Two or three sharp raps on the frame with a rawhide
hammer will often help to align the bearings and free the armature.
2. If no difficulty is indicated in the above test, a stall torque test may be made to see if the starting
motor is producing its rated cranking power. Make test connections as shown in Figure 6.
3. If torque and current are not within specifications, check the seating of the brushes and internal con-
nections for high resistance. If these checks are made and found to be in good order, replace frame and
field assembly and retest starter.
PIPER AIRCRAFT
PA-32R-301/301T
MAINTENANCE MANUAL
80-10-00
Page 80-8
Reissued: July 1, 1993
4D18