Table 4-3. Unit Troubleshooting (Continued)
TEST OR INSPECTION
HYDRAULIC SYSTEM (Continued)
Check hydraulic pressure relief valve pressure setting by disconnecting gooseneck
from prime mover (Ref. paragraph 2-18), lowering platform to the ground and keeping
lever engaged until the cylinder dead ends. Check psi.
A reading of 2500 psi is only on gauge (1) when hydraulic controls
are in use. Readings will drop to 500 psi when levers are
The psi will vary due to load. Hydraulic pressures will vary from 300
to 2500 psi under normal operation, and will reach a maximum of
2500 to 2800 psi under full load.
If PSI reads more or less than 300 to 500 psi, reset hydraulic pressure (Ref.
Check throttle valve for obstruction
If throttle is clogged, clean throttle valve in accordance with paragraph 4-65.
Check cylinder for internal leaks.
Fully retract cylinder rod, disconnect and cap hydraulic hose connected opposite of
the rod end cylinder port. Apply pressure to rod end port and inspect for leakage
out of the open port. (Small drips more than 10 seconds apart are acceptable).
Do not exceed 3000 psi. Serious injury or death may occur if pressure
exceeds 3000 psi.
If more significant leakage is present, notify direct support maintenance for cylinder