Bendix Drive; Starting Motor Assembly - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
11-42. BENDIX DRIVE. The drive assembly should be thoroughly cleaned and relubricated at overhaul.
NOTE
DO NOT use carburetor cleaner or any cleaning solution that could
damage the rubber block inside the drive assembly.
a. Clean the drive assembly thoroughly to remove all dirt. grease. and contamination from the screw
shaft threads and control nut. Use only clean petroleum base cleaners such as kerosene or varsol. Depending
on the operational environment. it may be necessary to remove the drive cup to insure a thorough cleaning job.
DO NOT remove the control nut.
b.
After cleaning thoroughly. use compressed air and blow the assembly dry.
c.
Using a silicone spray. spray down the drive assembly and motor shaft assembly.
d.
When installing the early style drive assembly on the shaft make sure the "spiral pin" does not extend
beyond the outside diameter of the pinion sleeve. On the later style drive. make sure the head washer covers
both ends of the retaining pin.
11-43. ASSEMBLY.
a.
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. No dimensional specification for end play is necessary:
however. make sure the fiber thrust washer is on the drive end of the armature shaft and that a steel thrust
washer is on each end of the Drive Assembly Shaft.
NOTE
When assembling the end head on the motor make sure the letter
"R" is directly in line with the motor terminal. On MHB 4014 units.
assemble them such that the letter "L" is in line with the motor
terminal.
b. 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 I-I 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.
Revised: 10/5/83
ELECTRICAL SYSTEM
3D16