INSPECTION AND REPAIR

(8)

Remove pole piece screws (51, pole pieces (50), strips (49) and fields (52).

6-209. CLEANING. Clean as follows:

(1) Remove as much dirt as practical from parts, with compressed air.

(2) Wipe remaining dirt from parts with a cloth slightly moistened with solvent. Do not wet armature or field

windings.

(3) Clean commutator to bright finish with commutator stone. Do not use emery cloth.

6-210. INSPECTION AND REPAIR. Inspect and repair as follows:

(1) If balancing machine is available, check that armature dynamic balance is within one inch-ounce, at 3000

revolutions per minute.

(2) Measure commutator runout. If in excess of 0.002 inch total indicator reading, turn in lathe, truing

commutator within above limits, and holding copper surface smoothness to less than 33 micro-inches. This finish may

be obtained, after lathe turning, with commutator stone.

(3) Check brush length of used brushes by comparing them with new brush. If brushes have less than one-

half length of new brushes, replace them, as they probably will not last until next disassembly.

(4) Make a high potential test above ground on all windings, using I 15 volt test light or ohmmeter.

(5) With motor on test operation for five minutes, check for bearing heating, unusual noises from bearings or

brushes, and for vibration.

(6) Watch action of brushes on commutator. Excessive sparking of brushes indicates worn or sticking

brushes, weak brush springs, defective armature or commutator.

(7) Inspect area around commutator and brush covers for thrown solder from commutator, indicating that

motor has been overheated in operation, or armature is shorted. If this condition is found, replace armature.

(8) Repair is limited to soldering loose solder joint connections, truing commutator in a lathe, and replacing

defective parts.

6-211. ASSEMBLY. Reverse procedure in paragraph 6-207.

6-212. STEERING PUMP MOTOR.

6213. DISASSEMBLY. Clean motor exterior thoroughly with solvent before beginning disassembly. Disassemble only

as far as necessary, as follows:

(1) Relieve pressure of brush springs (8, figure 7-32) on brushes (15) and remove brushes.

CAUTION

Do not pull brushes out by leads if they might be serviceable. Leads may be damaged.

(2) Remove screws (3) from both end bells (1 and 2). Separate end yokes from field frame (14). Remove

armature (l 3).

(3) Remove screws (16), washers (17), and remove brush holder (5) from commutator end bell. If they are to

be replaced, pull bearings (9 and 10) from end bells..

(4) Remove screws, nuts and washers attaching terminal poles, and field windings (21, 22, 23 and 24), and

remove poles and field windings.

6-214. INSPECTION. Inspect as follows:

(1) With motor on test operation for five minutes at 6 to 12 volts, check for bearing heating, unusual noises

from bearings or brushes, and for vibration.

(2) Watch action of brushes on commutator. Excessive sparking of brushes indicates worn or sticking

brushes, weak brush springs, defective armature or commutator.

(3) Compare used brush length with a new brush from stock. If less than half length of new brush, install new

brushes.

(4) Inspect area around commutator and brush covers for thrown solder from commutator, indicating that

motor has been overheated in operation, or armature is shorted. If this condition is found, replace armature.

6-215. REPAIR. Repair is limited to soldering loose solder joint connections, truing commutator in a lathe, and replacing

defective parts.

6-216. ASSEMBLY. Reverse procedures in paragraph 6212.

6-217. TEST.

(1) With motor installed and pump connected for operation, disconnect one lead and connect an ammeter in

series between the lead and the motor terminal from which the lead was disconnected.

(2) Operate motor and check for current draw of about 18 amperes unloaded (not steering) at truck battery

voltage.

6-218. SC RELAY.

6-219. DISASSEMBLY. Disassemble only as far as necessary to perform necessary repairs, as follows:

6-47