9
Inspection
and Part
Preparation
After the parts have been cleaned,
they should be inspected for nicks,
burrs and stubborn residue. The gears
and the edges of the gear plate pockets
are the most likely areas to be damaged
because of sharp edges. An illuminated
magnifier facilitates examination.
1.
All flat surfaces of plates and gears
should be “blocked”. Blocking is the
act of rubbing the flat surface of a part
on 400-grit, 500-grit or 3/0 abrasive
paper, which is supported on a
machinist’s or inspector’s surface
plate. A few light but firm rubs usually
are enough to remove residue and
minor metal disturbances.
Remember
to use a figure 8 pattern to retain flat-
ness and perpendicularity of holes
when lapping plates.
1.
Heavy disturbances or residue on
front or rear plates (NOT the gear
plate!) may require stronger blocking
on 320-grit or even 240-grit abrasive
paper followed by blocking on a finer
abrasive paper. Deep score marks or
metal transfer cannot be removed by
blocking, and the surfaces must be
ground. When surfaces are ground,
care must be taken to maintain the
perpendicularity of the precision
ground holes with the inner plate sur-
face. The gear plate should never be
ground; to do so would reduce the
axial gear clearance to the point
where interference might occur when
the pump is reassembled. Gears can
be ground as well, but interchange-
ability and clearances are altered.
Grinding gears is NOT recommended!
2.
Gears, shafts and arbors should be
lightly polished on the O.D.
3.
Any nicks in the gear teeth should be
removed by carefully stoning the
parts with a fine India oilstone or an
Arkansas stone.
4.
The edges of the gear’s I.D., bearing
holes and dowel holes should be
lightly stoned with a round Arkansas
stone to remove any nicks. Then polish
the I.D. with a small piece of fine
abrasive paper, 400-grit or finer.
5.
After all preparation has been com-
pleted, remove the abrasive grain
and loose residue in an ultrasonic
cleaner or other suitable cleaning
method. Abrasive grain is larger in
size than the pump clearances.
6.
At this point, dimensional inspection
may be made if desired.
B-9000 Series
Disassembly
(continued)
the adapter plate to the pump
body. Lift the adapter plate off the
pump body and retrieve the O-
Ring.
4.
Loosen and remove the socket head
screws (19) and (20) from the back
of the rear plate (7).
5.
Remove the rear plate (7). Always
use the pry slots to prevent scratching
precision tapped surfaces.
6.
Remove the gear plate (3), being
careful to note the alignment of any
markings on the plate. Always use
the pry slots to prevent scratching
the plates.
Caution:
Do not allow metering gears to
be lifted out with the gear plate. They
may drop, causing damage to the gear
teeth. Note that the slip-fit dowels (10)
may come off with the gear plate.
7.
Remove the retaining ring (16) from
the shaft (2) which holds the driving
gear (5) in place.
8.
Remove the driving gear (5).
9.
Remove the round key (4).
10.
Remove the drive shaft (2) from the
front plate (8).
11.
Remove the driven gear (6) from the
arbor (9).
12.
Remove the slip-fit dowels (10) by
turning and pulling simultaneously.
13.
If the arbor (9) is to be replaced or
thoroughly checked, press out by
using an arbor press, pressing
toward the inside of the pump (the
shortest press distance).
14.
Replace sleeve bearings (32 & 34)
in front and rear plates as necessary
and hone in the plate to the original
new part specifications. Contact
Zenith for dimensions.
NOTE:
.05
through 2.4 cc/rev models do not
have sleeve bearings.
