ARO PM20 Series, Operator'S Manual

Page: 7 / 12

PM20X-X-X-BXX (en) Page 7 of 12
PARTS LIST / PM20X-X-X-BXX AIR MOTOR SECTION

Indicates parts included in 637421 Air Section Service Kit shown below and items (70), (144), (175), (180) shown on page 5.
AIR MOTOR SECTION SERVICE
Service is divided into two parts - 1. Pilot Valve, 2. Major
Valve.
GENERAL REASSEMBLY NOTES:
y
Air motor section service is continued from fluid section
repair.
y
Inspect and replace old parts with new parts as neces-
sary. Look for deep scratches on metallic surfaces, and
nicks or cuts in “O” rings.
y
Take precautions to prevent cutting “O” rings upon instal-
lation.
y
Lubricate “O” rings with Lubriplate FML-2 grease.
y
Do not over-tighten fasteners, refer to torque specifica-
tion block on view.
y
Re-torque fasteners following re-start.
y
Service Tools - To aid in the installation of (168) “O” rings
onto the (167) pilot piston, use tool #204130-T, available
from ARO.
PILOT VALVE DISASSEMBLY
1. A light tap on (118) should expose the opposite (121)
sleeve, (167) pilot piston and other parts.
2. Remove (170) sleeve. Inspect inner bore of sleeve for
damage.
PILOT VALVE REASSEMBLY
1. Clean and lubricate parts not being replaced from service
kit.
2. Install new (171 and 172) “O” rings. Replace (170) sleeve.
3. Install new (168) “O” rings and (169) seal - Note the lip di-
rection. Lubricate and replace (167) pilot piston.
4. Reassemble remaining parts. Replace (173 and 174) “O”
rings.
MAJOR VALVE DISASSEMBLY
1. Remove (135) valve block and (233) adapter plate, expos-
ing (166 and 132) gaskets and (176) checks.
2. Remove (233) adapter plate, releasing (140) valve insert,
(141) valve plate, (199, 200 and 241) gaskets and (231,
243 and 244) “O” rings.
3. Remove (136) plug and (137) “O” ring, releasing (111)
spool.
MAJOR VALVE REASSEMBLY
1. Install new (138 and 139) “U” cups on (111) spool -
LIPS
MUST FACE EACH OTHER
.
2. Insert (111) spool into (135) valve housing.
3. Install (137 and 242) “O” rings on (136) plug and assemble
plug to (135) valve housing, securing with (105) screws.
AIR MOTOR PARTS LIST
Item Description
(size)
(Qty) Part No. [Mtl] Item Description
(size)
(Qty) Part No. [Mtl]
74 Plug (2) Y17-51-S [SS]
101
Center Body
(PM20A-X-X-BXX)
(1) 97031 [A]
(PM20S-X-X-BXX)
(1) 97040 [SS]
103 Bushing (1) 97394 [D]
105 Screw
(M6 x 1 - 6g x 20 mm)
(4) 95887 [SS]
111 Spool (1) 95651 [D]
118 Actuator Pin
(0.250” x 2.276” long)
(2) 94083 [SS]
121 Sleeve (2) 94084 [D]
126 Plug (1) Y17-13-S [SS]
127 900 St.Elbow
(1-1/2-11-1/2 NPT)
(1) 94860 [C/I]
128 Set Screw
(1/4” - 20 x 1/4”)
(2) Y29-42-S [SS]

132 Gasket (1) 94099 [B]
133
Lockwasher
(1/4”) (PM20A-X-X-BXX)
(3) Y117-416-C [C]
(PM20S-X-X-BXX)
(3) Y14-416-T [SS]
134 Screw
(M6 x 1 - 6g x 35 mm)
(4) 95923 [SS]
135
Valve Housing
(PM20A-X-X-B02)
(1) 96334-1 [A]
(PM20S-X-X-B02)
(1) 96337-1 [SS]
136
Plug
(PM20A-X-X-BXX)
(1) 96335 [A]
(PM20S-X-X-BXX)
(1) 96339 [SS]

137 “O” Ring
(1/16” x 2” OD)
(1) Y325-32 [B]

138 “U” Cup
(3/16” x 1.792” OD)
(1) 95966 [B]

139 “U” Cup
(3/16” x 1-1/4” OD)
(1) Y186-50 [B]
140 Valve Insert (1) 95650 [Ck]
141 Valve Plate (1) 95659 [Ck]

146 “O” Ring
(3/32” x 1-1/16” OD)
(1) Y325-118 [B]

147 “O” Ring
(1/8” x 1/2” OD)
(2) Y325-202 [B]

166 Track Gasket
(1) 94026 [B]

167 Pilot Piston
(includes 168 and 169)
(1) 67164 [D]
168 “O” Ring
(3/32” x 5/8” OD)
(2) 94433 [U]
169 “U” Cup
(1/8" x 7/8" OD)
(1) Y240-9 [B]
170 Piston Sleeve (1) 94081 [D]

171 “O” Ring
(3/32” x 1-1/8” OD)
(1) Y325-119 [B]

172 “O” Ring
(1/16” x 1-1/8” OD)
(1) Y325-22 [B]

173 “O” Ring
(1/16” x 1-3/8” OD)
(2) Y325-26 [B]

174 “O” Ring
(1/8” x 1/2” OD)
(2) Y325-202 [B]

176 Diaphragm
(check valve)
(2) 94102 [SP]

199 Track Gasket (1) 95666 [B]

200 Gasket (1) 95665 [B]
201 Muffler
(includes item 127)
(1) 67213
233
Adapter Plate
(PM20A-X-X-BXX)
(1) 96336 [A]
(PM20S-X-X-BXX)
(1) 96338 [SS]
240 Screw
(M6 x 1 - 6g x 16 mm)
(2) 95991 [SS]

241 Track Gasket (1) 96344 [B]

242 “O” Ring
(1/16” x 7/32” OD)
(1) Y325-5 [B]

243 “O” Ring
(1/8” x 5/8” OD)
(1) Y325-204 [B]

244 “O” Ring
(1/8” x 7/8” OD)
(1) Y325-208 [B]

Lubriplate FML-2 Grease (1) 94276
Lubriplate Grease, 10 Pack 637308

Used on models PM20S-CSS-XXX-BXX only

Used on models PM20A-CSS-XXX-BXX only

Fluid Section Kit parts, see page 5.