Gradall G-550C Operation And Maintenance Manual page 29

G-660C & G-880C GRADALL (Crawler)
There are three basic guides to determine when pins and
bushings should be turned. They are:
1.
When the (current) wear line on the drive side of the
sprocket teeth approaches 1/4" of the tips (if this is
not the first set of bushings used with this sprocket or
if the bushings have been turned previously, a second
wear line may be apparent).
2. .120" external bushing wear. Three methods of
measuring this wear are shown below.
.120" internal pin and bushing wear (pull the track
3.
tight and measure across four track links-five pins)
to get an average wear figure-the master pin must
not be within the section of track being measured.
Use all three checks. When any one of these situations
occur, the pins and bushings should be turned.
Note-The internal or external wear can be allowed to approach .190" when working in sandy conditions
where the bushings are not subjected to shock loading from rough terrain and where excessive bushing loading
from dirt built up in the sprocket roots is not a possibility. However, when in doubt, remember that it's better
to turn pins and bushings too early rather than too late.
The following dimensions can be used as a guide for
determining when the wear to the outside of the
bushing is enough to warrant turning or replacement.
MODEL NEW
G-660C 2.062"
G-880C 2.125"
25% 50% 75%
2.046" 2.031" 2.015" 1.984"
2.109" 2.093" 2.076" 2.062"
100%
29
OPERATION & MAINTENANCE