19
MAINTENANCE SECTION
DISASSEMBLY
General Instructions
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Never apply excessive pressure by a holding device
which may cause distortion of a part.
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Apply pressure evenly to parts, which have a press
fit.
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Apply even pressure to the bearing race that will be
press fitted to the mating part.
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Use correct tools and fixtures when servicing this
tool.
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Don’t damage “O” Rings when servicing this tool.
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Use only genuine ARO replacement parts for this
tool.
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When ordering, specify part number, description, tool
model number and serial number.
Disassembly of Motor:
1. Remove Sanding Pad (34).
2. Remove Lock Ring (27) and pull Motor and Seal (21)
from Housing.
3. Remove Retaining Ring (18).
4. Using special brass blocks to fit around outside diam-
eter of Cylinder, clamp around Cylinder and press
Shaft of Counterbalance through Bearing (19) and
End Plate (20).
5. Remove Blades (24), Rotor (23), and Key (28).
6. Remove End Plate (25) and Bearing (19).
Throttle Disassembly:
1. Remove Vacuum Adapter (15) (if applicable) by
pressing in on tabs and pulling Vacuum Adapter out.
2. Remove Inlet Adapter (13), releasing Spring (12) &
Valve (11). Note: Do not remove seat (10) unless
damage is evident.
3. Remove Muffler (14).
4. To remove Valve Stem (6), remove Roll Pin (8) and
Lever (7).
Regulator Disassembly:
1. Remove Lever (7) by removing Roll Pin (8).
2. Remove Snap Ring (5) from Regulator (3).
3. Remove regulator assembly (3) -- includes 2
“O” Rings (4).
ASSEMBLY
Assembly of Motor:
1. Grease and assemble “O” Ring (26) to Lock Ring (27).
2. Assemble Lock Ring over Counterbalance (29).
3. Assemble Bearing (19) into End Plate (25), pressing
on outer race of Bearing.
4. Assemble End Plate (25) onto Shaft of Counterbal-
ance, pressing on inner race of Bearing.
5. Install Key (28) in key slot.
6. Assemble Rotor (23) to Counterbalance, aligning
key--way to Key (28).
7. Assemble Five rotor blades (24) to Rotor Slots.
8. Assemble Cylinder (21) over Rotor, aligning Roll Pin
in Cylinder with slot in End Plate.
9. Assemble Bearing (19) into End Plate (20), pressing
on outer race of Bearing.
10. Assemble End Plate (20), with Bearing (19), to Coun-
terbalance, pressing on inner race of Bearing.
Note:
Align slot in End Plate with Roll Pin in Cylinder.
11. Install Retaining Ring (18) to groove in Counterbal-
ance, with bow in ring positioned as shown in parts
illustration page.
12. Assemble Seal (22) to grooves in Cylinder.
13. Assemble Motor to Housing, aligning Seal (22) with
air inlet.
14. Tighten Lock Ring (27), securing Motor Assembly.
15. Assemble Sanding Pad (34) and tighten securely.
Throttle Assembly:
1. Coat Valve Stem (6) with ARO 29665 spindle oil and
assemble into Housing with hole in Valve Stem in
line with Housing to accept Valve (11).
2. Assemble Seat (10) into Housing with rounded cor-
ners into housing first.
3. Coat Valve (11) with ARO 29665 spindle oil and as-
semble into housing, securing Valve Stem (6).
4. Assemble Spring (12) into Housing.
5. Assemble Inlet Adapter (13) to Housing, securing
throttle components.
6. Assemble Lever (7) to Housing, securing with Roll
Pin (8).
7. Assemble Vacuum Adapter (15) or Plug (16) to
Housing. To assemble Vacuum Adapter, push into
Housing until tabs on Vacuum Adapter snap into slots
in Housing. To assemble Plug, push into Housing
until it is flush with port opening.
Regulator Assembly:
1. Assemble Regulator (3) and 2 “O” Rings (4).
2. Insert Regulator assembly (3) into Housing (1).
3. Assemble Snap--Ring (5) into groove on regulator
assembly (3).
4. Install Lever (7) by adding Roll Pin (8).
