Figure 3-84. Measuring for shims.

taking care that bar stock is flat on face of pinion gear

7. Install the required shims and reinstall

and does not ride on the shaft.

differential assembly on carrier.

4. Using a feeler gauge, measure the

8. Install caps and secure with screws.

remaining distance between bar stock and outside

9. Using a dial indicator, check ring gear

diameter of differential case.

laterally for backlash at four position (90 degrees apart).

5. Add the thickness of bar stock and feeler

Backlash should be 0.005 and 0.010 inch.

gauge measurement. The total measurement will be

Caution: When adjusting backlash, rotate

referred to as sum A.

each adjusting nut exactly the same distance to

Note. A measurement is etched on the pinion

maintain proper bearing preload.

gear and ring gear. Insure both measurements are

10. Backlash is increased by removing lock,

identical, then record the measurement.

loosening adjusting nut nearest ring gear, and tightening

6. If measurement is a + (plus), then add it to

opposite nut.

0.156 inch.

11. Backlash is decreased by removing lock,

7. If measurement is a (minus), then subtract

loosening adjusting nut farthest from ring gear, and

it from 0.156 inch.

tightening opposite nut.

8. The result obtained in step 6 or 7 will be

(17) The remaining reassembly and installation is

referred to as sum B.

in the reverse order of disassembly.

9. Subtract sum A from sum B.

The

(18) Attach motor and carrier to drive axle housing.

difference is the thickness of shims required between

(19) Install drive unit assembly in lift truck.

carrier housing and drive motor housing.

(20) Install drive wheels.

10. Measure and install the required shims on

(21) Install mast assembly and attach forks.

the drive motor.

(22) Connect all lines, hoses, cables, etc.

11. Reinstall and secure the carrier.

(23) Replace fluids in differential and hydraulic oil

reservoir (LO 10-3930-620-12).

(24) Bleed brake system (TM 10-3930-620121.

3-48. Drive Motor

a. General. The drive motor is a dc series wound,

flange mounted type. A replaceable armature shaft is

employed, mounted on a sealed bearing at the

commutator end and a double row thrust bearing at the

drive end. Dual metal graphite brushes are supported in

fixed, box type holders to assure proper brush alignment.

A metal clip on top of each brush forms a stop device

that prevents commutator scoring.

b. Brush and Brushholder Service. Brushes can be

replaced without removing the drive motor from the

truck, as follows:

(1) Disconnect

battery

and

discharge

capactiors (para 2-5).

Figure 3-84. Measuring for shims.

(2) Remove the toe and the floor plates (TM

(b) Differential case removed from carrier.

10-3930-620-12).

1. Remove screws securing carrier caps and

(3) Remove the rear cover from around the

remove caps.

stator.

2. Remove differential assembly from carrier.

(4) Remove brush retaining screws, lift brush

3. Place a flat piece of 1.2220 inch thick bar

retaining springs, and withdraw brushes from brush

stock on the pinion gear of the motor.

holder. (fig. 3-85)

Note. Bottom side should be drilled out so

Note. Before new brushes are installed. they

that armature shaft does not prevent bar from lying

should be contoured on a sanding drum with the

flat.

same diameter as the commutator. Hold brushes to

4. Place a piece of round bar stock

sanding drum to obtain the same radius and brush

approximately 7 1/ 4 inches long by 3.142 inches

angle on contact face as was on old brushes. Final

diameter across carrier.

seating can be maintained with a fine mesh seating

5. Measure distance between bar stock and

stone while conmmutatior is turning.

add amount etched on pinion gear.

6. Subtract measurement obtained in step 5.

from 0.040. inch to obtain total measurement of

required shims.

3-95