10.2 MONTHLY MAINTENANCE
10.2.1 Check inner cylinder end ring clearance
Drop impact block out approximately 5".
Run come-along around impact block and
lead and pull impact block towards the lead.
Measure clearance between inner cylinder
end ring and neck of impact block with feel-
er gauge. If clearance approaches 50/1000"
(1.25mm), replace inner cylinder end ring.
(See section 10.3.)
Wear beyond 50/1000" (1.25mm) causes ex-
cessive wear on lower cylinder and even-
tually will crack the lower cylinder, and will
10.2.2 Check compression. Place hammer on an
already driven pile and make a cold blow.
Observe piston through pick-up slot on
upper cylinder. The piston should rebound
at least eight times (pronounced rebounds)
If not, change piston rings. (See section
10.2.3 Check catch groove on upper cylinder.
Corners must be square (Fig. 23).
10.3 CHANGING INNER CYLINDER END RING,
PISTON RINGS, AND/OR RUBBER RING
IN VERTICAL POSITION
10.3.1 Block up drive cap on ground and detach
drive cap cables. Drive cap must be level.
10.3.2 Set hammer on drive cap.
10.3.3 Raise piston by means of tripping device so
piston barely shows at top of upper cylinder
(just as you would fill the oil chamber).
10.3.4 Remove oil plug and install eye bolt instead.
10.3.5 Attach second crane line to eye bolt (Fig. 24).
10.3.6 Carefully lower piston via tripping device
until the trip can be engaged to the lifting
blocks on upper cylinder.
10.3.7 Put strain on hammer line and piston line,
but do not lift the piston or the hammer.
10.3.8 Release piston from tripping device by strik-
ing the trip cam lever with a hand hammer
10.3.9 Lower piston via crane line until this line