Hitachi EX1900-5, Operator'S Manual

Page: 242 / 281

MAINTENANCE
7-110
Check and Adjust Track Sag --- every 50
hours
CAUTION: Be sure to place blocks under the ma-
chine frame to support the machine when one
track is raised off ground.
Swing the upperstructure 90° and lower the bucket to raise
the track off the ground as shown.
Keep the angle between the boom and arm 90 to 110
°
and position the bucket’s round side on the ground. Place
blocks under the machine frame to support the machine.
Rotate track one full rotation. Thoroughly clean track area
to remove soil.
Measure distance (A) at the middle of the track frame from
the bottom of the track frame to the back face of the track
shoe.
Track sag specifications --- 570 to 640 mm
(22.4 in to 25.2 in)
NOTE: When operating the machine on sand, gravel,
snow or mud, providing longer track sag is rec-
ommended in the above-mentioned value
range.
Precautions for Adjusting Track Sag
1. When measuring track sag after adjusting, be sure to
rotate the raised track one full rotation.
2. When adjusting track sag, lower the bucket to the
ground to raise one track off the ground.
Repeat this procedure to raise the other track.
Each time, be sure to place blocks under the machine
frame to support the machine.
3. When operating the machine after it has been stored
for a long time or its track adjuster cylinder hose or
piping has been replaced, first push the right travel
lever forward to extend adjuster cylinder, and then
add grease to the fitting to tighten the tracks.
M117-05-030
M115-07-170
Track shoe back face
A
Track frame
bottom
90 to
110
°