DISTRIBUTOR.

d. Inspection and test.

(1) Inspect field coils for worn or frayed

(1) Turn commutator on lathe, if more than 0.002

insulation; corroded, loose or burned terminal stud

inch out of round, burned, or if mica projects above 88

assembly; and loose and/or corroded connections.

commutator copper segments. Do not undercut mica

between segments.

(2) Inspect brushes for excessive wear and oil

saturation and brush springs for corrosion and lost

(2) If burned contact disc can be cleaned up

tension.

without removal of much metal, clean by filing to bright

finish.

(3) Using .lamp and two probes, test armature

for ground. Place one probe on commutator and the

f. Assembly. Reverse b above.

other probe on the laminated core. If test lamp lights,

armature is grounded. Replace it.

g. Installation. Reverse a above.

(4) Using growler, test armature circuits. If

6-55. DISTRIBUTOR.

shorted circuit is discovered, clean between all bars of

commutator; then retest. If open circuit is indicated,

a. Removal.

replace armature.

(1) Loosen screw at distributor primary terminal

(5) Replace defective items.

and remove primary circuit lead-in wire.

(6) Inspect brushes for excessive wear (beyond

(2) Snap clips from distributor cap and lift cap

one-half the length of a new brush), and loose or frayed

from distributor. Do not remove wires from cap.

brush leads. Replace defective brushes with new ones.

Sand new brushes with No. 00 sandpaper. Hold

(3) Chalk mark edge of distributor to indicate

sandpaper against commutator, grit side against brush,

location of rotor tip before removal, loosen clamp screw

and pull sandpaper so that the brush is drawn to the

and lift out distributor.

brush arm. As brush is sanded, it assumes the contour

of commutator.

NOTE

Do not turn engine crankshaft until

(7) Springs. Inspect springs for wear, rust, or

distributor is reinstalled.

corrosion, loss of tension, and evidence of overheating.

Springs should hold brushes firmly against commutator.

b. Disassembly.

Replace defective springs with new ones.

(1) Remove distributor cap and rotor. Remove

(8) Field frame.

seal from distributor body.

(a) Using a test light, check field frame, field coils,

(2) Disconnect lead from contact set and remove

and terminal studs for ground. Hold one test probe on

contact set and condenser.

the terminal stud and the other test probe on the field

frame. If lamp lights, a ground is present. To locate the

(3) Remove breaker plate. Remove centrifugal

ground, remove terminal stud and field coil lead from

advance springs carefully.

frame. Place one test probe on terminal stud and other

test probe on field frame. If lamp fails to light, ground is

CAUTION

between terminal stud and field frame. If lamp does

The tension of these springs is

light, ground is between field coils and pole shoes on

calibrated to control the automatic

field frame.

spark advance mechanism.

They

must not be stretched or distorted, or

(b) Using same test light, test field coils for open

engine performance will be affected.

circuit by placing one test probe on each of leads coming

Lift advance weights from pivots on

from the field coils. If lamp lights, no open circuit is

shaft plate.

present. If lamp does not light, an open circuit is

present.

(4) File or grind off peened overhead of pin and drive out

pin. Remove gear, shims and washer, then take shaft

e. Repair.

from distributor body.