Figure 4-1. Hydraulic pump disassembly and reassembly.

1 Seal

14 Relief spring

2 Seal

15 Relief port plug

3 Mounting flange

16 O-ring

4 O-ring

17 Plug

5 Packing

18 Body

6 O-ring

19 Body dowel

7 Bushing

20 Valve spool spring

8 Bushing dowel

21 Spool

9 O-ring

22 O-ring

10 Setscrew

23 Plug

11 Spring

24 Bushing

12 Relief valve cone

25 Drive gear

13 Spool

26 Idler gear

Figure 4-1. Hydraulic pump disassembly and reassembly.

4-3. Hydraulic Control Valve

assembly only as far as is necessary.

a. Description. The hydraulic system control valve

(1) Separate the control valve into its major

sections by removing nuts (19) from tie rods (44) and slip

contains two plunger sections; an inlet section, and an

the sections off of tie rods.

outlet section. Each of the sections may be replaced

(2) Disassemble defective sections using

separately. All parts of the sections may be replaced

figure 4-2 as a guide.

individually except the plunger section housings and their

d. Cleaning and Inspection.

selectively-fit plungers, which must be replaced as units.

b. Removal. Refer to paragraph 2-12 for hydraulic

(1) Clean all parts in (SPEC. P-S-661).

(2) Inspect springs for cracks, wear,

control valve removal.

c. Disassembly. Refer to figure 4-2 and

deformation, or signs of weakness.

(3) Inspect all seals for cracks, cuts, or other

disassemble as follows:

damage.

CAUTION

(4) Inspect all machined surfaces for nicks,

It is extremely important that all parts

scratches, gouges, or other damage which could cause

be kept clean at all times, and that all

internal or external leakage.

machined surfaces be protected from

(5) Inspect all housings for cracks, stripped

nicks, scoring, gouging, and other

damage.

Disassemble

valve

4-3