JLG E450A, Service And Maintenance Manual, Page: 209 / 480

SECTION 5 - BASIC HYDRAULIC INFORMATION & SCHEMATICS
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Double Wrench Method
To prevent undesired hose or connector rotation, two
wrenches must be used; one torque wrench and one backup
wrench. If two wrenches are not used, inadvertent component
rotation may occur which absorbs torque and causes
improper joint load and leads to leaks. For hose connections,
the ‘layline’ printed on the hose is a good indicator of proper
hose installation. A twisted lay-line usually indicates the hose
is twisted. See Figure 5-12. for double wrench method require-
ments.
Figure 5-12. Double Wrench Method