JLG M4069 ANSI Service Manual - Manual (Page 25)

SECTION 2 - GENERAL
3121122 – JLG Lift – 2-5
2.4 CYLINDER DRIFT TEST
Maximum acceptable cylinder drift is to be measured
using the following methods.
Platform Drift
Measure the drift of the platform to the ground. Fully ele-
vate the platform. Maximum allowable drift is 2 in. (5 cm)
in 10 minutes. If the machine does not pass this test, pro-
ceed with the following.
Cylinder Drift
Drift is to be measured at the cylinder rod with a calibrated
dial indicator. The cylinder oil must be at ambient temper-
ature and temperature stabilized.
The cylinder must have the normal load, which is the nor-
mal platform load applied.
If the cylinder passes this test, it is acceptable.
NOTE: This information is based on 6 drops per minute cyl-
inder leakage.
2.5 PINS AND COMPOSITE BEARING REPAIR
GUIDELINES
Filament wound bearings.
1. Pinned joints should be disassembled and
inspected if the following occurs:
a. Excessive sloppiness in joints.
b. Noise originating from the joint during operation.
2. Filament wound bearings should be replaced if any
of the following is observed:
a. Frayed or separated fibers on the liner surface.
b. Cracked or damaged liner backing.
c. Bearings that have moved or spun in their hous-
ing.
d. Debris embedded in liner surface.
3. Pins should be replaced if any of the following is
observed (pin should be properly cleaned prior to
inspection):
a. Detectable wear in the bearing area.
b. Flaking, pealing, scoring, or scratches on the pin
surface.
c. Rusting of the pin in the bearing area.
4. Re-assembly of pinned joints using filament wound
bearings.
a. Housing should be blown out to remove all dirt
and debris...bearings and bearing housings
must be free of all contamination.
b. Bearing / pins should be cleaned with a solvent
to remove all grease and oil...filament wound
bearing are a dry joint and should not be lubri-
cated.
c. Pins should be inspected to ensure it is free of
burrs, nicks, and scratches which would dam-
age the bearing during installation and opera-
tion.
Table 2-2. Cylinder Drift
Cylinder Bore Diameter
Max. Acceptable Drift
in 10 Minutes
inches mm inches mm
3 76.2 0.026 0.66
3.5 89 0.019 0.48
4 101.6 0.015 0.38
5 127 0.009 0.22
6 152.4 0.006 0.15
7 177.8 0.005 0.13