Hawk Industries Hawkjaw Sr. Manual ALS Serial Numbers 1 to 100 - Manual (Page 72)

Trouble Shooting
Symptom Remedy
Movement
at Start-up
(cont)
z
Make sure the hydraulic power unit is shut down.
Press the Grip button repeatedly to bleed hydraulic
pressure. Access the main hydraulic block. See
Maintenance & Repair, p. 66, Drawings p. 114, 128.
At start-up, no air should reach the Raise/Lower
hydraulic valve VR/L at Port A or B. Push in the
"E" stop button. Disconnect the black Raise air
hose to Port B. To disconnect the air hose, push the
hose and collet ring into the valve pilot port. While
holding down the collet ring, pull out the air hose.
Place your hand over the disconnected air hose, and
pull out the "E" stop button. No air should come
out of the hose. If air comes out of the hose, replace
the air logic system. See Maintenance & Repair, p.
66, Drawings, p. 126. Repeat for the Lower button.
The green Lower air hose connects to Port A on the
Raise/Lower hydraulic valve VR/L. If no air comes
out of either air hose when the "E" stop is pulled out,
replace the Raise/Lower hydraulic valve VR/L. See
Maintenance & Repair, p. 66, Drawings, p. 114, 128.
z
If the Tilt Forward or Tilt Back button is stuck in, the
Tilt cylinder will operate. If the Tilt Forward or
Tilt Back button sticks, screw off the button, and
clean thoroughly. If the button still sticks, replace
the Tilt Forward or Tilt Back button air valve. See
Drawings, p. 130, 128.
z
Make sure the hydraulic power unit is shut down.
Press the Grip button repeatedly to bleed hydraulic
pressure. Push in the Tilt Forward button. Air
should sound like it is being sharply inhaled.
Release the button. Air should sound like it is being
sharply exhaled. If these sounds do not occur,
replace the Tilt Forward button air valve. Repeat
for the Tilt Back button. See Drawings, p. 130, 128.
Raise/Lower cylinder moves.
(cont.)
Tilt cylinder moves.
72 Troubleshooting
Continued on next page.