JLG 450A_AJ Series II Service Manual - Manual (Page 121)

SECTION 3 - CHASSIS & TURNTABLE
3121180 – JLG Lift – 3-71
Check Turntable To Bearing Bolts
1. Fully retract boom and elevate to 70 degrees (full
elevation).Try and insert a 0.0015" feeler gauge
between bolt head and hardened washer at posi-
tions shown in Figure 3-52., Swing Bearing Feeler
Gauge Check.
2. Lower boom to horizontal and fully extend boom.
3. Try and insert a 0.0015" feeler gauge between bolt
head and hardened washer at position indicated by
arrow in Figure 3-52., Swing Bearing Feeler Gauge
Check.
Wear Tolerance
1. Position boom over side of machine with upper
boom horizontal, telescope fully extended, and mid/
lower boom stowed. Measure and record distance
between swing bearing and turntable using a mag-
netic base dial indicator.
2. At same point, position boom over side of machine
with Upper Boom and Mid/Lower Boom fully ele-
vated. Measure and record distance between swing
bearing and turntable using a magnetic base dial
indicator.
3. If there is a difference greater than 0.057" (1.40 mm),
replace swing bearing.
4. If there is a difference less than 0.057" (1.40 mm)
and any of the following conditions exist, remove
and inspect bearing.
a. Metal particles in grease.
b. Increased drive power.
c. Noise.
d. Rough rotation.
5. If bearing inspection shows no defects, reassemble
bearing and return to service.
.0015" Feeler Gauge
Figure 3-52. Swing Bearing Feeler Gauge Check
SWING
BEARING
FRAME REF.
TURNTABLE REF.
MEASURING
POINT
Figure 3-53. Swing Bearing Tolerance Measuring Point