MI-290AG
Rev. 4
7
Replacement/Removal of air motor drive coupling (8) (see parts list PL 46340: p13)
First, follow procedure above for “Removal of #46340 Air Motor Drive”. With a rubber
mallet tap the coupling (8) to dislodge it from the gear reducer (10).
Align the key way on the coupling (8) with the key (9) on the gear reducer (10) shaft and
lightly tap the coupling (8) till the coupling (8) bottoms on the gear reducer (10) shaft. By
reversing the above steps you will be able to remove the coupling (8) from the gear reducer (10)
shaft.
Note:
The coupling (8) on the gear reducer (10) shaft has a press fit so the coupling (8) does
not come apart during assembly or disassembly.
Replacement of o-rings (3) in upper bushing retainer (2) (see parts list PL 290AG: p10)
If it has not already been done, remove the air motor sub-assembly per the previous
instructions. Now carefully press out the groove pin (8). Loosen the upper bushing retainer (2)
and remove it from the shaft (9). Remove o-rings (3), gasket (22) and retainer (2) and replace
with new parts.
Note:
If the o-ring (5) in the adjustable flange assembly (5-7) is going to be replaced it should
be done now. See replacement of o-ring in adjustable flange section below.
Reinstall the upper bushing retainer (2) with the gasket (22) by carefully sliding both
parts over the shaft (9). Replace groove pin (8). Thread retainer (2) into the inlet body (4) and
tighten. Attach the air motor assembly (1) per the previous instructions.
Replacement of o-ring (5) in adjustable flange (7) (see parts list PL 290AG: p10)
With the air motor (1), groove pin (8), and upper bushing retainer (2) removed, remove
the drive link retainer screw (18), and drive link (21). Note the position of the drive link tabs.
Remove lower bushing retainer (15) that also includes the shaft bushing (16), and o-ring (3).
Now slide the shaft (9) out of the unit. Next remove either the inlet body (4) or bevel gear sub-
assembly (11) including the rotary housing (13) and nozzle hub (19) from the extension tube
(10). Loosen the three set screws (6) and slide the flange assembly (7) off the extension tube
(10). Replace the o-ring (5) and reassemble flange onto the extension tube (10). Reassemble
all parts onto the unit. Make sure all parts are tightened before start up of the unit making sure
that the drive link (17) is installed with tabs in the same position noted earlier.
