OPERATOR’S MANUAL AF1260-XX

INCLUDING: SERVICE KITS, TROUBLESHOOTING, PARTS LIST, RELEASED: 8-16-10

DISASSEMBLY AND REASSEMBLY. REVISED: 10-28-23
(REV: H)
12” AIR MOTORS
6” STROKE
Also covers 637489 service kits
READ THIS MANUAL CAREFULLY BEFORE INSTALLING,
OPERATING OR SERVICING THIS EQUIPMENT.
It is the responsibility of the employer to place this information in the hands of the operator. Keep for future reference.

THIS MANUAL COVERS THE FOLLOWING MODELS

MODEL
AF1260 AF1260-01

SERVICE KITS
y Use only genuine ARO® replacement parts to assure
compatible pressure rating and longest service life.
y 637489 for general repair of all air motors.
GENERAL DESCRIPTION
WARNING DO NOT EXCEED MAXIMUM OPERATING
PRESSURE AS INDICATED ON PUMP MODEL PLATE.
WARNING REFER TO GENERAL INFORMATION SHEET
FOR ADDITIONAL SAFETY PRECAUTIONS AND
IMPORTANT INFORMATION.
y This manual only covers the air motor section. It is one of AF1260 AF1260-01
four documents which support an ARO pump. Replace-
ment copies of these forms are available upon request. Figure 1
 Pump Model Operator’s Manual.
 General Information for Air Operated or Hydraulically OPERATING AND SAFETY PRECAUTIONS
Operated Pumps.
 Lower Pump End Operator’s Manual. y DO NOT EXCEED MAXIMUM AIR INLET PRESSURE OF
90 PSI (6.2 BAR) OR 75 CYCLES PER MINUTE.
 Air or Hydraulic Motor Operator’s Manual.
CAUTION High pressure equipment – Always
y The 12” air motor is a general purpose power unit and disconnect air supply and relieve material pressure
is used with many 2-ball and chop check pumps. It
utilizes tie rod type construction for easy breakdown and before attempting to service.
it connects to the various lower ends via tie rods for easy y A ground lug is located on the air motor. This ground
operation. Consult pump model operator’s manual for lug allows proper grounding of the pump.
specific instructions. MATERIAL CODE
MODEL DESCRIPTION CHART [A]
[B]
=
=
Aluminum
Buna Nitrile
[D]
[PP]
=
=
Acetal
Polypropylene
[Br] = Brass [SS] = Stainless Steel
A F 12 X X – XX [Bz] = Bronze [Ef] = Epoxy - Fiberglass Filament Reinforced
[C] = Carbon Steel [CK] = Ceramic
Air Motor Diameter
12 - 12” DISASSEMBLY OF AIR MOTOR
Stroke Length
6 - 6” NOTE: All threads are right hand.
1. Force the piston assembly up by pushing the (115) rod
Air Motor Base/Rod Combination toward the top of the air motor.
0 - Divorced pump base with quick coupled rod connection
(See Figure 3) 2. Remove the (201) muffler/muffler assembly for ease of
disassembly.
Air Motor Options 3. Remove the four (138) socket head screws from the (140)
01 – Integrated On/Off Valve and Regulator head manifold and the one (138) socket head screw form the
(122) head plate. Remove the (140) head manifold by pull-
ing up and outward to remove from tubes (114) and (137).
4. Remove (141) major gasket from the (140) head manifold.
(continued on page 3)

INGERSOLL RAND COMPANY INC

209 NORTH MAIN STREET – BRYAN, OHIO 43506
 (800) 276-4658  FAX (800) 266-7016 © 2023 CCN 15331416
arozone.com
 PARTS LIST / AF1260-XX
Item Description (Qty) Part No. [Mtl] 138 149
101 Base and Bearing (1) 66507-1 [A] 148
109 Nut (1/2” - 20) (8) Y11-8-C [C] 145
111 O-Ring (1/8” X 11 3/4” OD) (2) Y325-277 [B] 144
112 Cylinder (1) 96941 [Ef] 150
147 143
113 O-Ring (1/16” X 3/4” OD) (4) Y325-24 [B] 146 142
114 Tube (1) 96872 [C] 141
*115 Rod (1) [SS] 121
116 O-Ring (1/4” X 12” OD) (1) Y325-452 [B] 155
*117 Piston (1) [A] 127 138
*119 Bushing (1) [C]
140
*120 Trip Rod Assembly (1) [A]
113
121 Bolt (1/2” - 20 x 10 1/4”) (8) 94046-1 [C] 122
137 136
122 Head Plate (1) 96863 [A] 113 135
123 O-Ring (3/32” X 1/2” OD) (1) Y325-109 [B]
124 O-Ring (1/16” X 2” OD) (1) Y325-32 [B] 134
125 Cap (1) 96897 [D] 111
113 133
126 Sleeve (1) 96901 [Br/A] 132
127 Ground Lug (1) 96878 [Bz] 116 131
128 O-Ring (1/16” X 1 11/16” OD) (1) 96917 [B] 114 130
129
129 Snap Ring (1.180” OD) (1) Y147-7 [C] 128
130 Washer (1) 96894 [C] 117 126
131 Pin (1) 96895 [C] 113
125
132 Driver (1) 96868 [C]
124
133 U-Cup (3/16” X 1 1/2” OD) (1) 96908 [B] *203
Not User 119 123
134 Spool (1) 96875 [A] Serviceable
135 Vent Bushing (1) 96896 [D]
136 U-Cup (5/32” X 1 3/8” OD) (1) 96907 [B] 120
137 Tube (1) 96871 [C]
138 Socket Head Screw (5/16”-18 X 1”) (9) Y99-52-S [SS]
140 Head Manifold (1) 96858 [A]
141 Major Gasket (1) 96900 [B] 115
142 Valve Plate (1) 96884 [CK]
143 D-Valve (1) 96889-2 [D]
144 Valve Housing (1) 96866 [A]
145 Socket Head Screw (5/16”-18 X 4 1/2”) (2) Y99-516-S [SS]
146 Pilot Insert (1) 96882 [D]
147 Pilot Valve Plate (1) 96883 [CK] 112
148 Pilot Gasket (1) 96899 [B]
149 Vent Plug (1) 96906 [D]
150 Pilot Cover (1) 96865 [A] 154
152 U-Cup (1) Y186-24 [B]
153 Washer (1) 92216 [Br] 153
154 Snap Ring (1) Y147-237 [C] 152 TORQUE SEQUENCE

155 Muffler (1) 96916 [C] 111 7 5

201 Muffler Kit (Optional, See Fig. 4) (1) 67445-5 [C] 2 3

202 Regulator / Shut-Off
(Optional, See Fig. 4)
(1) 67442

*203 Piston Assembly (Includes items 115,

117, 119 and 120)
(1) 67499 101 4 1

Lubriplate 6 8
 (2) 94276 109
FML-2 Grease Packet (1/4 oz.)
 Items included in Service Kit (637489)
For simplification of ordering and stocking, the Universal Service Kit Figure 2
contains service parts that can be used for every size of air motor.
 TORQUE REQUIREMENTS 
When repairing the motor, use only the parts that are needed for NOTE: DO NOT OVERTIGHTEN FASTENERS.
that specific motor. Extra service parts from the kit will remain after Tighten (109 and 121) to 10-15 ft-lbs (13.6-20.3 Nm)
repair of the air motor. Tighten (138 and 145) to 50-60 in-lbs (5.6-6.8 Nm)
LUBRICATION / SEALANTS
 NOTE: Lubricate with Grease (ARO p/n 94276).

Page 2 of 8 AF1260-XX (en)

 DISASSEMBLY OF AIR MOTOR (CONT’D) 8. Assemble the eight (121) bolts thru the (122) head plate
and the (101) base assembly.
5. Remove tubes (114) and (137) by pulling upward. 9. Assemble the eight (109) nuts to (121) hex head bolts
6. Remove the four (113) O-rings from both tubes (114) and and tighten per specified torque sequence and value.
(137). 10. Pull the (120) trip rod assembly as far out of the air
7. Remove the (142) valve plate and the (143) D-valve from motor assembly as possible, slide the (123) O-ring over
the (144) valve housing. the (120) trip rod assembly and down into the gland
8. Remove the four (138) socket head screws to extract the found in the (122) head plate.
(150) pilot cover. 11. Slide the (125) cap over the (120) trip rod assembly and
9. Remove the (148) pilot gasket from the (150) pilot cover. down into the bore found in the (122) head plate.
10. Remove the (147) pilot valve plate and the (146) pilot 12. Slide the (129) snap ring first and the (130) washer
insert from the (144) valve housing. secondly, onto the (120) trip rod assembly.
11. Remove the two (145) socket head screws from the (144) 13. Slide the (132) driver onto the (120) trip rod assembly.
valve housing. Align the hole of the (132) driver with the hole in the
12. Remove the (144) valve housing by pulling straight up. (120) trip rod assembly and insert the (131) pin.
13. Remove the (124) O-ring, the (135) vent bushing, and the 14. Assemble the (133) U-cup to the (134) spool. Take note
(136) U-cup from the (144) valve housing. of the (133) U-cup lips should point down towards the
14. Remove the (128) O-ring and the (126) sleeve from the (122) head plate.
motor assembly by sliding it straight up. 15. Slide the (134) spool onto the (120) trip rod assembly over
15. Pull the (134) spool as far from the motor assembly as the (132) driver and insert the (130) washer behind it.
possible to expose the under side of the spool itself. Utilizing snap ring pliers, assemble the (129) snap ring to
16. Locate and remove the (129) snap ring from the (134) the internal groove found in the (134) spool. Be certain
spool utilizing snap ring pliers. that the (129) snap ring is fully engaged into the groove.
17. Lift to remove the (134) spool and remove the (133) Slide the (134) spool downward into the bore of the (122)
U-cup. head plate nesting on top of the (125) cap.
18. Slide the (131) pin to remove the (132) driver, (130) washer, 16. Lubricate the inside diameter of the (126) sleeve and slide
and (129) snap ring from the (120) trip rod assembly. it onto the (134) spool and locating it into the (125) cap.
19. Remove the eight (109) nuts from (121) hex head bolts. 17. Install the (128) O-ring onto the top gland of the (126)
20. Remove the eight (121) bolts from the (122) head plate sleeve.
and the (101) base assembly. 18. Install the (136) U-cup, the (135) vent bushing into the
21. Remove (122) head plate from the (112) air cylinder. center bottom bore of the (144) valve housing. Take note
22. Remove the (111) O-ring, the (125) cap, and (123) O-ring that the (136) U-cup lips must be facing up towards the
from the (122) head plate. top of the (144) valve housing. Install the (124) O-ring
23. Pull upward on (112) air cylinder until (203) piston into the bottom recess gland of the (144) valve housing.
assembly separates from the (101) base assembly. If, in 19. Install the (144) valve housing to the motor assembly
this step, the (203) piston assembly is not pulled from by sliding the center bore onto the (134) spool and the
the (101) base assembly, then remove it after removing (126) sleeve. Take caution not to dislodge any of the
the (112) air cylinder. O-rings (124 & 128). Take note to align the large valve
24. If the (112) air cylinder and (203) piston assembly are pocket on the side of the (144) valve housing towards
removed as one unit, then remove the (203) piston the notch in the (122) head plate.
assembly from the (112) air cylinder. 20. Install the two (145) socket head screws thru the (144)
25. Remove the (116) O-ring from the (117) piston. valve housing and thread into the (122) head plate. The
26. Remove the (111) O-ring from (101) base assembly. (144) valve housing may need to be rotated slightly to
27. Remove (154) snap ring, (153) washer, and (152) U-cup align the tapped holes. Tighten the (145) socket head
from the (101) base assembly. screws per specified torque value.
REASSEMBLY OF AIR MOTOR 21. Install the (146) pilot insert thru the (144) valve housing
and into the (134) spool. The (134) spool may need to
1. Apply grease to all O-rings, U-cups, and other rubber be turned to orient its’ shallower slot to face the smaller
goods before installing. pocket of the (144) valve housing.
2. Install (152) U-cup, (153) washer, and (154) snap ring into 22. Install the (147) pilot valve plate into the (144) valve
the (101) base assembly. housing covering the (146) pilot insert.
3. Install the (111) O-ring in the groove on the (101) base 23. Install the (148) pilot gasket into the (150) pilot cover
assembly. and assemble to the (144) valve block using four (138)
4. Install the (116) O-ring in the groove on the (117) piston. socket head screws. Tighten to torque specifications.
5. Push (115) piston rod thru the (101) base assembly, 24. Install the (143) D-valve thru the (144) valve housing and
being careful not to damage the lips of the (152) U-cup into the (134) spool.
or the (102) O-ring. 25. Install the (142) major valve plate with identification-
6. Lubricate the inside diameter of the (112) air cylinder and dimple facing outward into the (144) valve housing
slide it down over the (203) piston assembly and onto the covering the (143) D-valve.
(101) air motor base assembly. 26. Install the four (113) O-rings onto both (114 & 137) tubes.
7. Align notch in (122) head plate with the port in (101) base 27. Loosely install the (137) tube into the bore in the (122)
assembly and press the (122) head plate down until it is head plate.
seated against the (112) air cylinder. The (120) trip rod as- 28. Loosely install the (114) tube into the bore in the (101)
sembly must lead thru the center of the (122) head plate. base assembly.
(continued on page 4)

AF1260-XX (en) Page 3 of 8

 REASSEMBLY OF AIR MOTOR (CONT’D) Air Motor Base and Rod Combination
29. Install the (141) manifold gasket into the (140) mani-
fold and telescope onto both (114 & 137) tubes until
the (113) O-rings are seated. Fasten the (140) manifold
to the (144) valve block using four (138) socket head
screws. Install one (139) socket head screw thru the ear
of the (140) manifold into the (122) head plate. Tighten
all five (138 and 139) fasteners to torque specifications.
30. Install the (201) muffler/muffler assembly.

TROUBLESHOOTING
Air leakage out of main exhaust.
y Damaged (141) track gasket. Replace (141) track gasket.
y Worn (116) piston seal. Replace (116) piston seal.
Continual air leakage out (149) pilot exhaust.
y Worn (136) “U” cup. Damaged (148) track gasket. Replace
(136) “U” cup and (148) track gasket.
Air leakage out (149) pilot exhaust only during the down
TYPE -0-
stroke.
Divorced Base, Quick Coupled Rod
y Worn (133) “U” cup. Rolled or damaged (128) “O” ring.
66507-1 BASE and
Replace (133) “U” cup and (128) “O” ring.
67499 PISTON ASSEMBLY
Air leakage around (115) piston rod.
y Worn or damaged (152) “U” cup. Replace (152) “U” cup.
Figure 3

Available Options for AF1260-XX Air Motors

201
Optional
202 67445-5
Optional t
67442
Self-Relieving
Ball Valve
Regulator / Shut-O
(AF1260-01)

Figure 4

Page 4 of 8 AF1260-XX (en)

 DIMENSIONAL DATA

Dimensions shown are for reference only, they are displayed in inches.

(2.75) (2.56)

(1 1/4 - 11 1/2 NPTF-1)

MAJOR EXHAUST PORT
(1.62) (2.25)

(1/4-18 NPTF-1)
PILOT EXHAUST PORT

(3.80) (2.00) (3.00)

(2.50)

(1/2-14 NPTF-1)
AIR INLET PORT

(4.06) (3/4-14 NPTF-1)

AIR INLET PORT
(7.90)

(2.53)

(21.00)

(16.50)
(23.08)

Figure 5

AF1260-XX (en) Page 5 of 8

Page 6 of 8 AF1260-XX (en)
AF1260-XX (en) Page 7 of 8
 PN 97999-1474
Page 8 of 8 AF1260-XX(en)