about 1980 (+ 25) rpm. Report any major deviations to
organizational maintenance.
3-27. Shovel Front Attachment Maintenance
a. Service. The shovel front must be lubricated
at the periodic intervals listed in the current LO. When
removed from the machine, all exposed finished
surfaces must also be lubricated as often as required to
prevent damage due to rust and corrosion. If possible,
the entire attachment should be placed inside a suitable
dry building, preferably on wooden blocking. The shovel
front should be cleaned using an approved cleaning
solution.
b. Adjust. Each of the following adjustments
must be checked after every 40 hours of shovel
operation. Adjust only if necessary.
(1) Saddle block adjustment. Shims and
wear plates are used to adjust the clearance between the
dipper stick and the saddle block wear plates as shown
in figure 3-10.
The desired minimum clearances
between wear plates and saddle blocks are 1/64 inch at
each location. Adjustment is mandatory when clearance
reaches 1 /16 inch at any point illustrated. Use the
following procedure for adjustment:
(a) Support the dipper stick in a
horizontal position. using the hoist line.
(b) Divide the dipper stick into three
approximately equal lengths, using chalk marks or paint.
(c) Move the dipper stick back and forth
a few times to make sure it is free in the saddle blocks
and in its normal operating condition.
(d) Position the dipper stick so that the
outer third of the dipper stick. as measured by the chalk
or paint marks. is located in the saddle block. Measure
the clearance between the wear plates on each Fide of
the dipper stick and the dipper stick. Record the
clearance measured.
(e) Measure the clearance between the
top of the dipper stick and the wear plate at each end of
the saddle block and record this measured clearance.
(f) Repeat steps (d) and (e) above for
each of the other two marked sections of the dipper
stick, each time recording the measurements.
(g) Loosen wear plate bolts and insert
shims beneath the wear plates until the clearance
between the dipper stick and the wear plates is
Figure 3-9. Hydraulic system inspection.
approximately 1 /64 inch, at the thickest point of the
3-26. Tachometer Inspection
dipper stick. Adjust both top and side clearances in this
With the engine running, check tachometer reading. At
manner. Shims are slotted so that they may be tapped
low idle, the reading should be about 500 rpm
into place without removing the wear plates.
(revolutions per minute). At governed speed (high idle)
the reading may be as high as 2.800 rpm. Under full
load, the reading should be
3-12
