Finish Thompson UC (S/N 125040 and lower) - Manual (Page 16)

16
Impeller Bushings
Removal
1. Remove the impeller (item 3, 3A) according to the steps listed in the section Impeller Assembly, Removal.
2. Place the impeller drive assembly (items 4,4A, 4B, 4C) on an arbor press with the front of the impeller drive
facing down.
3. Insert a 1” diameter arbor into the bore of the impeller drive assembly
(see figure 21).
4. Press on face of rear impeller bushing until (2) bushings (item 4A) and
(1) spacer (item 4B) have been removed. Check for excessive wear (see figure 13).
5. Check the impeller bore for signs of plastic melting or fretting wear.
Replacement
1. Place a piece of tubing with an ID of 1 ¼” at the rear center of the impeller drive
assembly (see figure 22). This tubing protects the lip that the bushing stops
against. Place the impeller and impeller drive assembly in an arbor press with the
suction side up.
2. Start the rear bushing into bore of impeller while lining up slots inside of the
bushing with the drive ribs in the bore of the impeller. The interrupted face end
of the bushing should be facing down. Press the bushing into the bottom of the
impeller bore with a 1” diameter soft-faced arbor. The bushing slides in easily in
the beginning of the bore, then
becomes tighter. The bushing spacer can then be placed in the bore of the impeller on top of the first bushing.
3. The front bushing can then be installed as in step #2. The interrupted face of the bushing should be facing up.
The front bushing will slide easily into place. A small portion of the rear impeller bushing projects out of the
impeller bore. This is normal.
4. Reinstall the impeller according to the steps listed in the section Impeller Assembly, Replacement.
figure 21
figure 22
Replacement
1. Place the impeller drive assembly in an arbor press with the rear sealing ring facing down.
2. Align the kidney-shaped drive pins on the impeller assembly with the kidney-shaped slots in
the impeller drive assembly and press partially in by hand.
3. Complete installation by pressing the impeller assembly into the impeller drive assembly
with an appropriate size arbor (be sure the arbor does not touch the impeller thrust ring,
item 3A, use an arbor with a larger diameter than the eye of the impeller) until the back side
of impeller rear shroud is flush with front face of impeller drive assembly (see figure 20).
figure 20
Impeller Assembly Removal and Replacement
The impeller assembly can be replaced as required to change the impeller diameter or
replace damaged or worn vanes.
Removal
1. Holding the impeller and impeller drive assembly (items 3,3A, 4,4A, 4B, 4C) by
hand, place a 3/8-inch diameter rod (or a 3/8” ratchet extension) through the
perforations in the bore of the impeller drive assembly (item 4).
2. While holding the impeller drive assembly tap on the rod with a hammer in several
locations until the impeller assembly separates from the impeller drive assembly. See figure 19).
figure 19