F
OR
M
ODELS
: JGI, JGM, JGN, JGP
AND
JGQ
S
ECTION
5 - M
AINTENANCE
PAGE 5-15
cent turned up throw. Push down and set indicator to zero.
d. Gently lift crankshaft with the strap until the needle on dial indicator stops
moving, repeat to be sure the reading is accurate. This is best done before
the connecting rods are installed by putting a clean lifting strap around the
adjacent pin and pulling up on the crankshaft with the strap.
e. Repeat Paragraphs a. through d. for each main bearing.
3.
Measure the crankshaft thrust clearance as follows:
a. As shown in Figure 5-11 on Page 5-16, install a magnetic stand on the top of
#1 main bearing cap, with a button type dial indicator placed against the side
of the adjacent crankshaft web.
b. Use an appropriate pry bar against the compressor frame and thrust the
crankshaft tight toward the dial indicator. Release pressure on the pry bar.
Hold crankshaft in place with minimum pressure to keep it from moving. Set
the dial indicator to zero. Then pry on the crankshaft to thrust in the opposite
direction tight and release pressure. Hold the crankshaft in place with mini-
mum pressure to keep it from moving to determine thrust clearance. Repeat
to be sure the reading is accurate. Note that crankshaft thrust clearance can
also be checked externally with the coupling disconnected and without
removing the top covers.
c. If thrust clearance is out of limits, replace thrust plates at #1 main bearing
F
IGURE
5-10 M
EASURING
C
RANKSHAFT
J
OURNAL
B
EARING
V
ERTICAL
J
ACK
C
LEARANCE
- T
YPICAL
Dial Indicator Magnetic Stand Placement
on Top of the Main Bearing Cap
Needle Type Dial Indicator Placement
on Top of Crankshaft Web
Lifting Strap Placement, Completely around Crankshaft Web - Attach Lifting Straps to Crane