TM 5-4310-379-14
4-21. Valve Operating Mechanism (Cont).
c.
Repair. (figure 4-24).
NOTE
Tag parts as they are disassembled to ensure they are installed in their original location.
(1)
Remove two bolts (1) from brackets (2) and remove shaft (3).
(2)
Unscrew upper push rods (4) from rocker arms (5) and separate upper push rods (4) from retainer (6),
springs (7), and push rod spring seats (8).
WARNING
Dry cleaning solvent PD-680 used to clean parts is potentially dangerous to personnel and property. Avoid
repeated and prolonged skin contact. Do not use near open flame or excessive heat. Flash point of
solvent is 100-138°F (38-600C).
(3)
Clean all items with dry cleaning solvent and dry thoroughly.
(4)
Clean out oil passages in bolts (1) and shaft (3).
NOTE
The current push rods have milled wrench flats and a bright turned finish. The lower spring seats are
serrated along the push rod contact surface. When replacing a push rod or spring seat, do not use a
former type spring seat with a current type push rod. All other combinations are permissible.
(5)
Inspect upper push rods (4) and push rod spring seats (8) for wear, and replace if worn, scored or
otherwise damaged.
(6)
Inspect ends of lower push rods (9) for wear and scuff marks, and replace if worn or otherwise damaged.
(7)
Inspect push rod springs (7) for defects and check spring with spring tester. Replace a spring (7) when a
load of less than 172 lbs compresses the spring to a length of 2 1/8 in. (5.39 cm) or less.
(8)
Inspect push rod seats (10). Measure outside diameter of push rod seats (10). Diameter of push rod seat
(10) should be 1.0580-1.0585 in. (2.7873-2.6835 cm). Replace a worn or otherwise damaged push rod
seat (10).
(9)
Inspect rocker arm shaft (3). Measure diameter of shaft (3) at points where rocker arms (5) ride on shaft
(3). Measurement should be .08735-.8740 (2.2187-2.2189 cm). Replace a worn or otherwise damaged
shaft (3).
(10)
Inspect rocker arms (5). Measure inside diameter of rocker arm bushings (11). Diameter should be .8650-
.8660 in. (2.222-2.2250 cm). Replace a worn rocker arm.
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