CHAPTER 4. OVERHAUL INSTRUCTIONS

CHAPTER 4

OVERHAUL INSTRUCTIONS

4-1.

SCOPE This section contains instructions for overhauling the pumping assembly.

Refer to NM 5-2805-259-14- for engine overhauling instructions.

4-2.

ENGINE AND PUMP ASSEMBLY SEPARATION (Fig. 4-1)

A. Remove the engine and pump assembly (para. 3-18).

B. Remove the eight nuts (44) securing the volute casing (28) to the intermediate housing (31). Remove the volute

casing from the intermediate housing. Remove the housing gasket (24).

CAUTION: Carefully maintain alignment when separating the volute casing (28) from the intermediate housing (31).

Damage to the impeller (19) will result if the volute casing is allowed to sway or turn during removal.

C. Insert a piece of wood between any two ribs of the impeller (19) and strike the wood with a mallet in such a

manner as to turn the trailing edge of the impeller blades counterclockwise. This will break the contact between the

thread in the impeller and the thread of the impeller shaft (38).

NOTE: If the edges of the impeller ribs are chipped or damaged, the impeller will be thrown out of balance. To correct

this condition, it is necessary to file the edges of the impeller ribs so that they are all alike.

D. Unscrew and remove the impeller (19), the spacer shims (20), the shaft sleeve (26) with the seal rotary elements

(22) from the impeller shaft (38). CAUTION: If the original impeller (19), shaft sleeve (26), seal plate (25), inter-mediate

housing (31). and impeller shaft (38) are to be used on reassembly, use of the original spacer shims (20) in the same

quantity and thickness will assure proper impeller spacing at reassembly.

E. Remove the seal plate (25) from the intermediate housing (31). Remove the seal stationary elements (23) from

the seal plate (25).

F. Remove the eight cap screws (46) and lock washers (47) securing the intermediate housing (31) to the engine

and remove the intermediate housing (31) and the intermediate guard (45).

4-3.

INTERMEDIATE HOUSING (Fig. 4-1)

A. REMOVAL - Refer to para. 4-2 and remove the intermediate housing.

B. DISASSEMBLY

1. Remove snapring (37). pull out impeller shaft (38). Remove oil seal (32), and bearing retainer (36) from shaft (38).

2. Remove retaining rings (34) and bearing (35) from impeller shaft (38).

3. Remove oil seal (32) from intermediate housing (31).

4. Remove the four screws (40) and lock washers (41) securing the spline coupling (42) to the engine flywheel and

remove the spline coupling. Remove the pilot bushing (43) from the spline coupling.

C. CLEANING, INSPECTION, AND REPAIR

1. Clean all parts with an approved cleaning solvent. Dry thoroughly.

2. Inspect parts for cracks, breaks, damaged threads, and other damage. Inspect bearing for free and smooth rotation.

3. Replace bearing if any roughness is detected, replace oil seals.

4. Rechase threads or replace hardware as needed.

5. Inspect the shaft and coupling splines and the pilot bushing bore. Replace all components that are worn, chipped or

damaged.