F
OR
M
ODELS
: JGI, JGM, JGN, JGP
AND
JGQ
S
ECTION
5 - M
AINTENANCE
PAGE 5-28
their toughness in service, rings are fragile with regard to removal. Always han-
dle them with clean tools and hands protecting the rings from nicks, marring,
and bending. Move the piston out of the cylinder until a fraction of the first ring
clears the cylinder. Encircle the ring by hand until it is clear and remove it. Use
this same procedure to remove the succeeding rings and wear band, if applica-
ble.
4.
Slide the piston rod out of the head end. The threaded crosshead end of the rod
is 1/8 inches (3 mm) smaller in diameter than the inside diameter of the packing.
Using extreme care, slowly slide the piston rod through the packing to avoid
damaging the rod threads or the packing rings.
Piston and Rod Disassembly
The Piston and Rod Clamping Fixture shown in the Figure will be useful for the piston and
rod disassembly and reassembly operations. This fixture may be purchased from Ariel.
1.
F
IGURE
5-21 P
ISTON
AND
R
OD
C
LAMPING
F
IXTURE
Piston Rod Clamping Fixture D-0961
Spanner - bolts onto piston
nut using (2) 5/16”-18 x
1-1/4” long Cap Screws
Compressor Piston
Piston Nut
Key Wrench
(Two Required
for each Tight-
ening of Set
Screws)
Clamp the piston and rod
assembly in the special
Clamping Fixture (D-0961),
using the bushing for a 1-1/8”
rod size (see Figure). Tighten
the four 12-point cap screws
to prevent the rod from turn-
ing. The fixture will properly
hold the piston rod to prevent
damage to the parts and pro-
mote safety during disas-
sembly and reassembly. The
Clamping Fixture must be
securely bolted down to pre-
vent it from turning with the
piston rod. It should be at a convenient height of approximately three feet or 0.9
meters. Remove the setscrews from the piston nut. Although the piston nut has
been staked to lock the setscrews, they can be forced out, by turning with an
Allen key wrench, past the small lip that has been formed.
2.
Remove piston nut using the piston turning/piston nut torquing tool (see Figure
7-1 on page 7-2). Two 5/16-18 x 1-1/4 in. bolts should be used to secure the tool
CAUTION
TRAPPED GAS PRESSURE IN HOLLOW PISTONS CAN
PRESENT A PERSONAL SAFETY HAZARD WHEN SERVICING
THE PISTON AND ROD ASSEMBLY. WORK IN A WELL
VENTILATED, NON SPARKING AREA. DO NOT BREATHE GAS
EMITTED FROM PISTONS WHEN VENTING TRAPPED GAS.
!