Section II. REPAIR OF HYDRAULIC COMPONENTS

(5) Check the starter motor as follows:

(8) Remove the capscrew (27). washer (28),

(a) Check the armature for shorts by placing

and center bearing plate (29) from the drive end

housing (37). Remove the bushing (30).

it on a growler.

(b) Test the armature for grounds by

(9) Remove pin (32) and key (33). Use a

puller or press the drive mechanism (34) from the

placing one probe of a test lamp on the armature

shaft and place the other probe on each com-

armature (35).

mutator bar in turn. If the test lamp lights, the

(10) Remove the spacer (36) from the ar-

mature (35) .

armature is grounded and the starter motor must be

c. Cleaning, Inspection and Repair.

replaced.

(1) Clean the starter motor parts with suitable

(c) Using a test lamp, place the probes on

solvent, but do not use cleaning solvents on the

each of the field leads of the starter motor. If the

drive mechanism, armature and field coils. Dry the

lamp does not light, the coils are open and must be

parts thoroughly with compressed air.

replaced.

(2) Check the bushings for roughness, scoring,

(d) Place one probe of the test lamp on the

or , excessive c l e a r a n c e . T h e b u s h i n g r u n n i n g

field frame and the other probe on a field coil lead.

clearances are as follows: commutator end frame

If the test lamp lights, the starter motor terminal or

0.0090-0.00 13 in., center bushing and drive

one of the field coils forming a pair are grounded. If

housing bushing 0.0015-0.0050 in.

the ground cannot be located or repaired, replace

(3) Check the brush holders to be sure that

the starter.

they will properly hold the brushes against the

(e) Using the test lamp, place one of the

commutator. Check the spring for a tension of 35

probes on each of the brush holders in turn and the

ounces. Check the condition of the brushes; if

other probe on the commutator end frame. If the

pitted or worn to less than 1/2 their original length,

lamp lights, the brush holder is grounded due to

replace. Compare old brushes with a new one to

defective insulation. Replace the insulation and

determine extent of wear.

recheck.

(4) Carefully inspect the armature com-

d. Reassembly. Reassemble in reverse order of

mutator. If it is burned. rough, or out-of-round,

disassembly observing the following :

turn down and undercut the mica as follows:

(1) Apply a thin coating of grease before

(a) Place the armature in a lathe and turn

pressing on the drive mechanism (34, fig. 5-6).

down the commutator until true. Make sure that

Note. If the drive mechanism is rotated to the full

the cut is not made on the commutator riser bars.

extended lock position on the screw shaft during replacement

Do not cut closer than 3/16 in. from the riser bars.

or overhaul of starter motor. do not attempt to force it in the

The solder would be removed, thus weakening the

reverse direction. Install the drive even though it is fully ex-

coil connections.

tended. After the motor is installed on the engine and the

(b) Undercut the mica between the bars to a

engine starts, centrifugal force will unmesh the drive pinion

depth not exceeding 0.030 in. The undercut must

from the flywheel ring gear in the usual manner.

be the full width of the mica separation and flat at

(2) Place a few drops of oil on the bushings

the bottom. After the undercutting, the slots should

(30) before installing.

be cleaned out to remove any dirt or copper dust.

e. Installation. Refer to TM 10-3930-624-12 for

(c) The commutator should be sanded

the installation instructions for the starting motor.

lightly with No. 00 sandpaper to remove any burrs

left from undercutting.

Section II. REPAIR OF HYDRAULIC COMPONENTS

5.5. Hydraulic Pump

5-4. General

a. Removal.

The hydraulic system supplies fluid to operate the

(1) Remove the radiator grille TM 10-3930-

lift, tilt, and steering system. The hydraulic system

624-12).

consists basically of an oil reservoir, hydraulic

(2) Disconnect the hoses from the pump. Refer

pump, control valve, tilt cylinders, and primary and

to figure 5-7. T a g t h e l i n e s a n d c a p o r p l u g

secondary lift cylinders.

openings.

5-6