TM 5-3820-245-14&P
C. Reassembly Feed Assembly
1. Clean all parts thoroughly. Insert O-Ring and backup ring into O-Ring groove inside working barrel support
with backup ring on top of O-Ring. Lubricate O-Ring backup ring, inside threads in support and threads on
barrel. Screw support on barrel until it is tight. (Figure 6-23, Item #29 & 30).
2. Place barrel braces on barrel. Place bolts and nuts in the barrel braces and leave loose. Align holes in
braces with holes in support and place all bolts through holes and screw on nuts. Torque all barrel brace
nuts to 10 ft. lb. maximum.
3. Slide saddle over end of barrel to approximate location.
4. With machined end of kelly bar (Item #4) wrapped, slide bar into barrel starting through barrel support end
of assembly. The wrapping around the machined end of the bar will prevent damage to the wall of the
barrel while bar is being pushed through. Allow machined end of bar to extend approximately two feet out
top end of barrel.
5. Remove wrappings on end of bar and slide piston past machined area with I.D. threads toward end of bar.
6. Drive one of the bearing cones on bearing journal until it contacts shoulder. Place bearing cup on cone,
and drive other bearing cone into cup. Screw kelly bar nut on bar until bearing assembly shows no play,
but still turns freely. If cotter pin hole does not line up with slots in nut, it will be necessary to re-drill bar to
1/4 inch diameter. Install cotter pin.
7. Heat top end of piston (Item #26) (low temperature) with a torch, and with a plastic or rawhide hammer,
drive piston over bearing assembly until shoulder in piston contacts rear of bearing cup.
8. Screw piston plug into piston until it contacts front edge of bearing cup tight. If hole in plug is out of line
with hole in piston, it will be necessary to re-drill through piston and into plug approximately 3/16 inch.
Drive pin through piston and into plug until it swells and locks in place. File down portion of pin protruding-
out of piston.
9. Place piston rings into piston ring grooves with a ring expander tool. Check rings to be sure that they
function freely in grooves.
10. Lubricate piston and rings and secure ring compressor tightly over assembly. Insert a round rod through
auger pin hole in bar and pull -piston into barrel.
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