Piper Comanche PA-24 Service Manual page 716

PIPER COMANCHE SERVICE MANUAL
9-78. Overhaul. U during the aboye iDSpectiCII any indication of startin, motor difficulty
IS
I1Ote-d, the starting lDolOr should be removed from tbe eqiDe for cle."mg and repair.
9-79. R .... cwal. To remove the startinl motor from the al1line, first dilcOftaect the &round cable
!rom tbe battery post to prevent sbort circuitiD&. Disconnect
the
lead from the starting motor
terminal, then take out the mOWlting bolts. The motor can then be lifted off and taken to the
bench for overhaul.
9-80. Dllal .... ly.
•. Remoye the frame serews from the commutator end head and pull end head and armature
from frame.
Lilt
the btushes and lock in elevated position with brush sprin,s. Use a puller to "'-
moye the end head from the armature. Use a special bearing puller to remoye the sealed ball
bellnng from [be armature
shaft.
b. Remove the frame screws that secure the par
aouia,
to tbe frame. Rem ... bolts and
nuts
holdinl the par housinl to the pinion hOOlain, and separate the two Wlils. Pull Bendix shaft
from pinion housing. Do not lose the steel .pacer that is located on the pinion end of the shaft.
Remoye reduction par, woodruff key and steel spacer from shaft.
c, Tum the Bendix pinion
Wltil it
locks in the extended
pOlition.
Locate "spirol" pin and
use a punch to remoye. SUde drive assembly off the shaft. Do not attempt to disassemble the
drive and do
110t
dip it in cleaning solvent.
d. To
remove
the roller bearings from the
&ear
housing. use
an
arbor press and
the
correct
bearing arbor. DO NOT HA.'dMER OUT. Each part should be cleaned and inspected for excessiye
wear or damage Bearings should be checked for proper clearance and evidence o( roughness or
galling. Oil and dirt should be removed. from insulation and the conditicn
at
the U1sulation checked.
9-81. BrUlh ... Check the brushes to see that they slide freely in their bolders and make full
contact on the commutator. If worn to half their original length or less, they should
be
replaced.
9-82. Annatur ••
a. Check the commutatei' for W1even wear. excessive &lainl or evidence
of
excessive arcing.
If
only Slightly dirty, glazed or discolored. the commutator can be cleaned with 00 or 000 sand-
paper.
If
the commutator is rough or wom. it should be turned in a lathe. Refer to Figure 9-29b.
The armature shaft should be inspected for rouch beanng surfaces and rough or damaged splines.
b. To test the armatwe for grounds, a set of test probes connected in series WIth a llt)..volt
light should
be
used. Touch one probe to a ccmmutator segment ar..d the other to the armature
core If the test lamp lights, the armature is grounded and should be replaced.
c.
To test for shorted armature Calls, a powler is used. (Refer to Figure 9·291:.) The arma·
ture is placed en the growler and slowly rotated by hand while a Iteel strip is held over the core
50
that it passes over each armature core slo[' If a coil is snorted, tne steel strip WIll vibrate.
d. A quick check
(or
opens cllD be made by inspecting the tralling edge
(in
direction of ro-
tation) of the commutator segments for excessive discoloration. This condition indicates an open
cin:uit.
ELECTRICAL SYSTEM
ISSUED: 8118n2
3 C16