TM 55-4920-394-13&P
g.
If the switch does not meet test requirement, replace with a serviceable item.
h.
After completion of tests, relieve system pressure. Remove fitting with boss seal and reinstall
element and filter bowl.
4-20. Low Pressure Filter.
4-21. Replacing Low Pressure Filter Element. (Refer to para. 3-25).
4-22. Replacing Fill System Filter Element .
(Refer to
para. 3-24).
4-23. High Pressure Pump. Dimensional tolerances for moving parts of the high pressure pumps are critical.
Repair is limited to lapping the port plate to clean up the flat surfaces. Use an abrasive equal to Carborundum
finishing compound Grade A 280V8WS. Port plate face flatness must be within three helium light bands with
faces parallel within 0.0001 inch. Minimum plate thickness after lapping is 0.302 inch.
4-24. Disassembly Of High Pressure Pump .
(Refer to
Fig. 3-9).
a.
Remove one end of hose assembly (1) from fitting on port block (59).
b.
Remove four socket head cap screws (3) and remove pressure compensator with handwheel
control assembly (2) and gasket (4) from hanger housing (91). Refer to paragraph 4-28 for
disassembly of pressure compensator control.
c.
Remove four socket head screws (6) and remove pressure compensator assembly minimum
volume control section (5) and gasket (7) from hanger housing (91).
d. Remove twenty socket head screws (9) and remove end cap (8) and gasket (10) from hanger
housing (91).
e.
Reach inside hanger housing (91) and lower hanger (26) to expose four socket head cap screws
(12). Rescrew (12) and remove clevis assembly (11).
f.
Disassemble clevis assembly (11) as required by removing dowel pins (13) and needle bearings
(14).
g.
Remove socket head cap screws (16) from indicator link (15) and remove indicator link.
h.
Remove drive pin (18) and remove indicator pointer (17) from indicator shaft (21).
i.
Remove three screws (20) and remove indicator plate (19) from hanger housing.
j.
Pull indicator shaft (21) out of hanger housing and remove O Ring (22) from indicator shaft (21).
4-4