9-13. ROCKER ARM AND CROSSHEAD MAINTENANCE.
Remove. Remove the valve covers, rocker arms, crossheads, and rocker arm housings in accordance with
Dry cleaning solvent PD680, Type Ill, or equivalent, is flammable and moderately toxic to the
skin, eyes, and respiratory tract. Assure adequate ventilation. Skin, eye, and respiratory
protection is required to avoid injury to personnel.
Compressed air used for cleaning or drying can create airborne particles that may enter the
eyes. Pressure shall not exceed 30 psi (207 kPa). Wearing of goggles Is required to avoid
Injury to personnel.
Clean. Clean all parts in dry cleaning solvent PD-680, Type IIl, or equivalent, and blow dry with compressed air.
Inspect. (See Figure 9-1 and Figure 9-2.)
Inspect all capscrews for damaged or stripped threads.
Inspect the adjusting screws (16, Figure 9-2) and locknuts (15) for damaged or stripped threads.
Inspect the ball-ends of the adjusting screws (16) using a 0.250 inch (6.35 mm) radius gage, or check the
fit of the ball-end in a new push rod using Prussian blue compound. Ball-ends and socket seats shall show
a seating area of at least 80 percent.
Inspect the injector rocker arm ball socket seat (26) for a true fit on the injector link using Prussian blue
compound and a new injector link Ball socket seat shall show a seating area of at least 80 percent.
Inspect the intake and exhaust rocker arms (12 and 14) for wear, scoring, or galling at the crosshead
Using a small hole gage, or inside micrometer, check the rocker arm bushings (27 and 28) for wear.
Maximum diameter shall be in accordance with Table 1-4.
Inspect the rocker arm shaft (11) for scoring. Depth of scoring shall not exceed 0.003 inch (0.08 mm).
Using a micrometer caliper, check the diameter of the rocker arm shaft (11). Minimum diameter shall be in
accordance with Table 1 4.
Inspect the rocker am is (12, 13, and 14) adjusting screw holes for worn or stripped threads.
Inspect the valve crosshead adjusting screws (10, Figure 9-1) and nuts (9) for damaged or stripped
threads, and for adjusting screw wear on the valve contact face.
Inspect the valve crossheads (8) for thread damage, wear in the rocker arm contact area, and wear in the
valve contact area.
Using a small hole gage, check the crosshead guide hole for wear. Maximum diameter shall be in
accordance with Table 1-4.
Inspect the crossheads (8), rocker arm shaft (11, Figure 9-2), and rocker arms (12,13, and 14) using
fluorescent magnetic particle inspection in accordance with MIL-1-6868. No defects are permitted.
Inspect the rocker arm housing (20) and rocker arm cover (6) for stripped threads, cracks, and for nicks or
dents in the gasket and packing sealing areas. Replace the ring dowel (24) if defective.
Inspect the retainers (17) for distortion and cracks. Replace defective retainers.
Inspect the water transfer tubes (22) for cracks, out-of-round, and corrosion. Pay particular attention to the
packing grooves for corrosion that would interfere with proper sealing. Replace any defective tubes.
Repair or replace the defective parts in accordance with step d, below.