Hawk Industries Hawkjaw Sr. Manual ALS Serial Numbers 1 to 100 - Manual (Page 92)

Trouble Shooting
92 Troubleshooting
Symptom Remedy
Hydraulic fluid heats up. (cont.)
The Raise/Lower Cylinder
moves slower than usual, or the
HawkJaw sinks while it hangs.
the HawkJaw or the pressure relief valve setting on
the hydraulic power unit, the hydraulic fluid will heat
up rapidly.
z
There is a leak in the hydraulic system. See
Trouble Shooting, p. 89-90.
z
If there are no leaks in the hydraulic system, and the
pump pressure compensator setting is at 2500psi
on a known, tested hydraulic power unit, and the
hydraulic power unit pressure relief valve is set
400 psi above the pump pressure compensator
setting and the hydraulic fluid still heats up, then
the pressure relief valve setting on the HawkJaw
has been changed. The pressure relief valve adjust-
ment is set at Hawk Industries. Under no circum-
stances should this pressure relief valve be adjusted.
Adjusting the pressure relief valve setting voids
the warranty and can cause severe damage to the
HawkJaw and the hydraulic power unit and
shortens component life. However, if this valve has
been adjusted below 2800 psi, and the pressure
compensator setting is above 2500 psi, the hy-
draulic fluid will pass over the pressure relief valve.
This will heat up the hydraulic fluid rapidly. Properly
set the pressure relief valve adjustment. On a
known, tested hydraulic power unit, set the pump
pressure compensator setting at 2800 psi. Use
an allen wrench to rotate the pressure relief valve on
the Hawkjaw counter-clockwise until the
Hawkjaw pressure gage drops. Now turn clock-
wise. When the gage returns to 2800 psi and
holds, tighten the pressure relief valve lock nut.
Set the pump pressure compensator setting back
down to 2500 psi. See Maintenance & Repair, p. 66,
Drawings, p. 114.
z
Check to make sure the hydraulic power unit is
producing 2500 psi at 20-35 gpm.
Continued on next page.
Hydraulic
Fluid (cont)
Raise/Lower
Cylinder