Hitachi ZAXIS 120-6 class Operator's Manual page 414

Simple Method
1. Remove any deposits on mating parts of the tracks and
undercarriage (top/bottom rollers, idler, sprockets).
IMPORTANT: Accurate measurements cannot be taken if
there are deposits on mating parts of the tracks and
undercarriage (top/bottom rollers, idler, sprockets).
2. Move forward in the direction of idler (1), traveling a
distance equivalent to at least the length of ground
contact by the machine.
3. Stop the machine in a state where one of the track pins
(4) is directly over upper roller (2).
4. As shown in the illustration to the right, place the
straight rod (3) (squared timber etc.) on the section of
track between idler (1) and upper roller (2).
5. Measure the maximum sag between the upper
surface of the track and the bottom surface of the rod.
(Dimension B in the illustration)
Model
ZX120-6, 240-6 class
ZX160-6, 200-6, 300-6, 330-6
class
Adjust Track Sag
1. If track sag is not within the specified range, adjust
it by loosening or tightening the track (refer to the
procedures on the next page).
2. After adjusting the sag on both track, rotate the tracks
backward and forward to equalize the sag on both sides.
3. Recheck the track sag one more time. Readjust as
necessary.
d
CAUTION: When adjusting the sag with the track
raised, be sure to place blocks under the machine
frame to support the machine. During adjustment,
never put hands, feet, or other parts of the body
beneath the track.
MAINTENANCE
Appropriate sag B (mm)
20 to 40
15 to 35
7-120
3 B
1
2
2
MDFY-07-100
4
MDFY-07-101