TM 5-3820-245-14&P
5-3. FEED RAM ASSEMBLY TROUBLE SHOOTING (Continued)
CONDITION
PROBABLE CAUSE
REMEDY
Excessive whipping
Bent kelly bar.
Upon encountering this condi-
of kelly bar while
tion, immediately shut down
digging.
operation. With kelly bar
fully extended, locate bend
in kelly bar. If bow is more
than 4 feet from the drive,
the bar can be straightened
in the machine. If the bend
has occurred above 4 feet, the
bar must be removed from the
machine. Refer to feed ram
disassembly procedure.
Bar will extend
Piston assembly.
Rings have failed on pistons.
but not retract.
Refer to feed ram disassembly
procedure. Before assembling
check feed ram cylinder for
damage.
Too much time
Flow control valve
Adjust valve mounted in line
lapse when bar
not properly
to the bottom of the feed ram.
reaches bottom of
adjusted.
Screw in to increase bar speed
hole.
and out to decrease bar speed.
5-4. OPERATIONAL CYLINDERS TROUBLE SHOOTING
CONDITION
PROBABLE CAUSE
REMEDY
Leakage around
Normal packing wear.
Tighten adjusting nut on pack-
shafts.
ing glands equal amount.
Hydraulic cylinder
Worn piston packing.
Disassemble cylinders and re-
will not hold.
pack. All cylinders except
feed ram cylinder use 1/4"
Belmont packing.
Leakage around
Loose cylinder cap.
Remove from digger and dis-
thread.
assemble checking threads for
damage. Reassemble using
nylon ribbon tape sealer.
PAGE 55
