JLG 450A II Series, Service And Maintenance Manual

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SECTION 3 - CHASSIS & TURNTABLE
3-42 – JLG Lift – 3121290
Turntable Bearing Mounting Bolt Checks
NOTE:
Check must be performed after first 50 hours of machine
operation and every 600 hours of machine operation
thereafter. Replace missing or loose bolts with new bolts
and torque as specified after lubricating bolt threads with
JLG Thread Locking Compound PN 0100019. Recheck all
bolts for looseness after replacing and torquing individual
bolts.
Check Frame To Bearing Bolts
1. Fully retracted boom and elevate to 70° (full elevation).
2. Try and insert a 0.0015" feeler gauge between bolt head
and hardened washer at positions shown in Figure 3-37.,
Swing Bearing Feeler Gauge Check.
Figure 3-37. Swing Bearing Feeler Gauge Check
3. Ensure 0.0015" feeler gauge will not fit under bolt head
to bolt shank.
4. Swing turntable 90° and check selected bolts at that
position.
5. Continue rotating turntable at 90° intervals until sam-
pling of bolts are checked in all quadrants.
Check Turntable To Bearing Bolts
6. Fully retract boom and elevate to 70 degrees (full eleva-
tion).Try and insert a 0.0015" feeler gauge between bolt
head and hardened washer at positions shown in Figure
3-37., Swing Bearing Feeler Gauge Check.
7. Lower boom to horizontal and fully extend boom.
8. Try and insert a 0.0015" feeler gauge between bolt head
and hardened washer at position indicated by arrow in
Figure 3-37., Swing Bearing Feeler Gauge Check.
Wear Tolerance
Figure 3-38. Swing Bearing Tolerance Measuring Point
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 magnetic base dial
indicator.
2. At same point, position boom over side of machine with
Upper Boom and Mid/Lower Boom fully elevated. Mea-
sure 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.