Contact Point Adjustment.

TM 10-3930-627-12

d. Inspection.

With the

(1)

Inspect the shell for breaks and

distributor cap, rotor, and plate removed, and the rubbing

stripped threads.

block of movable contact at the high point of the cam,

(2) After removal ( a above), check the

check the contact point gap by inserting a 0.022 inch

spark plug insulation for breaks, cracks, or chips.

feeler gage between the contact points. If an adjustment

(3) Check for abnormal carbon deposits

is necessary, loosen the mounting screw and insert

and burned electrodes.

screwdriver blade in breaker plate opening to move the

e. Tests. Spark plugs may be tested on a spark

stationary point contact support until the proper gap is

attained. After adjustment is completed, tighten the

plug tester, using a good spark plug as standard.

f. Installation. Reverse procedures in a above.

mounting screw. Also, check points for alignment and

bend stationary point if necessary.

Use new gaskets and tighten to 25 to 30 foot-pounds of

torque.

4-36. Spark Plugs

a. Removal.

4-37. Ignition Coil

a. Replacement.

(1) Remove cables from spark plugs.

(2) Clean dirt and other foreign matter from

(1)

Disconnect primary leads and

spark plug wells and unscrew and remove spark plugs

suppressor capacitor lead at coil terminals.

Pull

and gaskets.

secondary lead from center of coil, leaving it connected

b. Cleaning.

to the distributor cap.

(1) Before removal from engine, spark

(2) Remove two attaching cap screws and

plugs may be cleaned by wiping with a dry rag.

take coil from cylinder head.

(2) After removal (a above), the spark

(3) Reverse steps (1) and (2) above to

plugs may be cleaned by sandblasting.

install coil.

c. Adjusting Gap. Adjust the spark plug gap to

b. Test. Test coil using portable or bench type

0.025 inch, using a round (wire) spark plug gage. To

coil tester according to instructions given by the maker of

obtain proper adjustment, bend the ground electrode

the tester. There is no repair of a defective coil.

only.

Section XI. TRANSMISSION

Organizational maintenance of the transmission is limited

4-38.

Transmission

and

Torque

Converter

to the requirements of LO 10-3930-627-12.

Maintenance

Section XII. HANDBRAKES

release hand brake, turn knurled knob at top of lever (1,

4-39. Hand Brake

fig. 4-18) to tighten adjustment and repeat test.

a. Adjustment.

(3) If the brake needs more adjustment

(1) Hand brake must be able to hold truck

than the knob provides, shorten the effective length of

in place when loaded to rated capacity and stopped on a

the cables (8 and 9) by adjusting the position of the nuts

15 degree incline.

at the top end of the cables. Be sure both cables apply

(2) Under conditions given above, apply

equal pressure to brakes.

hand brake and release foot brake. If truck moves,

4-23