F
OR
M
ODELS
: JGI, JGM, JGN, JGP
AND
JGQ
S
ECTION
5 - M
AINTENANCE
PAGE 5-12
rod assembly, see “Piston and Rod” on page 5-27.
6.
Turn the crankshaft to position the crosshead near to its outer dead center posi-
tion, remove the crosshead pin through bolt, lock nut, end-plates and pin. Crib
JGI models so that crosshead does not fall down.
7.
Turn the crankshaft to near the inner dead center position. Move the crosshead
to its outer dead center position to be free of the connecting rod. Be sure the
connecting rod does not drop and damage the crosshead guide surface.
8.
Rotate the crosshead 90 degrees and remove it through the guide opening.
9.
Check the crosshead pin to crosshead/bushing clearance, refer to Table 1-3 on
page 1-10. Wear on the pin can be determined by a visual inspection.
10. Replace the pin if necessary. If the bushings need to be replaced, hacksaw or
file to within 1/32 inches (1 mm) of their thickness, being careful not to cut into
the crosshead. They can then be easily drifted out.
11.
F
IGURE
5-9 I
NSTALLING
A
C
ROSSHEAD
B
USHING
About 3 tons (27
kN of Force
Crosshead
Cooled
Bushing
A press is required to install new bushings.
Do not use a hammer to force a bushing
into place as this will distort the bushing’s
bore. The new bushings are to be installed
in the crosshead by cooling the bushings
in a 95 percent alcohol with dry ice solu-
tion. The bushings need to be left in the
solution long enough to reach the same
temperature as the solution, about
-110°F (-80°C). Position the crosshead on
the press table so that the side receiving
the new bushing is supported directly, see
Figure. Quickly seat new bushings while
they are still very cold.
CAUTION!: DO NOT TOUCH COLD SURFACES
WITHOUT PROPER INSULATION TO
PREVENT INJURY. ALCOHOL IS FLAMMABLE AND SHOULD ONLY BE
USED IN OPEN AIR OR A WELL VENTILATED BUILDING. AVOID SPARKS
AND OPEN FLAME. AVOID ALCOHOL VAPORS WHICH CAN CAUSE
INJURY TO THE TISSUES OF THE NOSE AND EYES. AVOID EYE AND
SKIN CONTACT. USE NEOPRENE OR BUTYL GLOVES, MONO-GOGGLES
OR FACE-MASK AND IMPERMEABLE APRON. THE SOLUTION CON-
TAINS METHYL ALCOHOL AND IS POISONOUS IF INGESTED. SEE MAN-
UFACTURER'S MATERIAL SAFETY DATA SHEETS FOR MORE
INFORMATION. DO NOT RETURN SOLUTION TO A CLOSED CONTAINER
UNTIL IT HAS REACHED ROOM TEMPERATURE OR THE CONTAINER
MAY EXPLODE.
NOTE: ABSOLUTE CLEANLINESS IS REQUIRED OF BOTH THE CROSSHEAD AND
THE BUSHINGS TO PREVENT DIRT FROM ACCUMULATING BETWEEN THE
BUSHING AND CROSSHEAD BORE.
NOTE: THE SIDE OF THE CROSSHEAD RECEIVING THE NEW BUSHING SHOULD BE
SUPPORTED DIRECTLY TO PREVENT POSSIBLE CRUSHING OF THE
CROSSHEAD BY THE PRESS, SEE FIGURE 5-9 ON PAGE 1-12.
12. Visually inspect the shoe surfaces for scoring. Since they are constantly lubri-
cated under pressure during operation, there should be virtually no wear.