National Crane Published 08/16/19 Control # 112-05 9-23
500E2 SERVICE MANUAL CRANE INSTALLATION
6. Assemble and install the bolt and washer assembly
through the holes in plate (5) and install plate on outer
surface of the truck chassis.
7. Install crush plate (6) to the inside of chassis frame
channel. Ensure the crush plate is machined to properly
fit to the inside the frame channel of the truck chassis
conforming to the frame rail.
NOTE: Cut the plate and machine as necessary to fit
inside the truck frame.
8. Align and install bolt (3) passing through mounting holes
in crush plate (6) and aligning through inner mounting
holes in the turret.
9. Install the washer (4) and nuts (8) on top side of the
turret and snug tight.
10. Install the outer bolt and washer assembly in the outer
turret assembly mounting holes.
11. Snug all bolts arrays in a star pattern.
12. Tighten evenly in a star pattern until the direct tension
indicator (DTI) crush washer (7) compresses and the
silicone indicator is visible between the washers.
NOTE: The DTI crush washer cannot be re-used and must
be replaced if the studs are removed.
NOTE: Tighten the bolt assembly only until the DTI crush
washer (7) is adequately compressed and the
silicone indicator is visible regardless of the tension
value being applied.
Tension should be verified by inserting 0.127mm
(0.005 in) feeler gauge between the hardened
washer and the DTI crush washer in between each
bump of the DTI crush washer. An example of the
acceptable tension would be when the feeler
gauge will not enter half of the available places
right in the bolt shank. If it does, then the bolt
assembly will need to be tightened slightly more.
Maintaining proper tension torque value for bolts is extremely
important for structural strength, performance, and reliability
of the crane. Variations in torque can cause distortion,
binding, or complete separation of the turret from the frame.
Proper identification of bolt grade is important. When marked
as a high strength bolt (grade 8), the service technician must
be aware of bolt classifications and that he is installing a high
strength heat-treated tempered component and the bolt
must be installed according to specifications. Special
attention should be given to the existence of lubricant and
plating that will cause variation from dry tightening values.
When a high strength bolt is removed, or un-tightened, the
bolt must be replaced with a new bolt of the same
classification.
Torsion Box Mounting
1. Position the torsion box assembly onto the chassis
frame (Figure 9-1).
2. Attach the torsion box to frame using the bolt and plate
assembly procedure as referenced in Turret Mounting
on page 9-22.
3. Install plate, rear light (10) to rear of the torsion box
using attaching hardware capscrew (11), washer (12),
and locknut (13).
WARNING
When tightening nuts keep the plate parallel to truck
frame. Failure to do so causes uneven edge loading and
stud failure.
WARNING
Crushing Hazard!
It is mandatory that T-box attaching bolts be inspected
and re-tightened after the first 300 hours of crane
operation and every 500 hours thereafter. The bolts may
loosen and cause the crane to separate from the carrier
which will result in damage to the crane and possible
injury or death to personnel.
CAUTION
Repeated re-tightening may cause bolts to stretch. If bolts
keep working loose, they must be replaced with new bolts
and DTI of the proper grade and size.
WARNING
When tightening bottom nuts keep the plate parallel to
truck frame. Failure to do so causes uneven edge loading
and stud failure.
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