JLG X23J - X700AJ Service Manual - Manual (Page 147)

SECTION 3 - CHASSIS & TURNTABLE
3-120 – JLG Lift – 3121448
MAINTENANCE TASKS
INSPECTING THE MOUNTING BOLTS
IMPORTANT
TO COMPENSATE FOR SETTLING, THE BOLTS MUST
BE RETIGHTENED WITH THE PRESCRIBED TIGHT-
ENING TORQUE. RETIGHTENING MUST BE EXE-
C U T E D W I T H O U T E X E R T I N G A D D I T I O N A L
EXTERNAL STRESS ON THE BOLTED UNION.
Figure 3-197. Inspecting the mounting bolts
1. Detached bolt
Execution only by a specialist.
• Special tools required:
Torque wrench
Hydraulic clamping fixture
• Replace loose and detached bolts or nuts and washers
with new bolts, nuts and washers.
• Use the same bolt size and bolt quality.
IF A HYDRAULIC CLAMPING FIXTURE WAS USED TO
TIGHTEN THE BOLTS, THEN A HYDRAULIC CLAMP-
ING FIXTURE MUST ALSO BE USED TO CHECK THE
BOLT PRETENSION. ALWAYS USE THE SAME TIGHT-
ENING PROCEDURE AS SPECIFIED FOR INSTALLA-
TION OF THE SLEW DRIVE WHEN CHECKING THE
BOLTED UNION.
CHECKING THE TILTING CLEARANCE
Wear in the raceway system results in an increase in tilting
clearance. Consequently it is necessary to check the tilt-
ing clearance in accordance with the maintenance inter-
vals.
IF THE MAXIMUM PERMISSIBLE TILTING CLEARANCE INCREASE
IS REACHED, THEN THE SYSTEM MUST BE BROUGHT TO A
STANDSTILL AND THE SLEW DRIVE MUST BE REPLACED IMME-
DIATELY, AS SAFE OPERATION CAN NO LONGER BE ENSURED.
Checking the tilting clearance increase d
k
directly on
the slew drive
The measured value m1 determined at installation serves
as the base value ("Determination of tilting clearance").
• Determine the value mx as described in the "Determin-
ing the tilting clearance".
• Subtract the base value m1 from the value mx deter-
mined in the inspection measurement:
d
k
= mx – m1 ≤ d
k
perm
d
k
perm = 0.45 mm
d
k
perm = 0.0177 in
Checking the tilting clearance increase dk but not
directly on the slew drive
Proportionally convert the tilting clearance increase each
time a measurement is taken (after the installation mea-
surement) and compare with d
k
perm.