Ingersoll-Rand 3940P2Ti, Maintenance Information, Page: 3 / 8

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Assembly of the Throttle Mechanism
1. Apply O-ring lubricant to the O-rings and place them on the Throttle
Valve Bushing (8), large ring on the large diameter grooves, the two
smaller rings in the smaller grooves.
2. Insert the Throttle Valve Assembly (6), small end first, into the small
diameter of the Throttle Valve Bushing.
3. Align the slot in the Throttle Valve Assembly with the slot in the
Throttle Valve Bushing and replace the Trigger Retaining Pin (14).
Press on the Trigger (7).
4. Place the Impactool on the workbench with the handle pointing
toward you and the square drive upward. Align the hole in the
Throttle Valve Bushing Assembly with the hole in the Housing and
drive in the Throttle Valve Assembly Retaining Pin (15) from left
to
right .
Assembly of the Motor
NOTICE
Periodically, as experience indicates and always after
disassembly, clean the air strainer screen in the Inlet
Bushing (3). Torque the Inlet Bushing to 50 to 60 ft-lb (68
to 81 Nm).
Before assembling the Motor, wipe a thin film of oil on the Rotor (31), End
Plates (30 and 34), Cylinder (33), and Vanes (32).
1. Using a sleeve that will contact only the outer ring of the Front Rotor
Bearing (35), press the bearing into the Front End Plate (34).
2. Slide the Front End Plate (34), bronze face first, over the splined hub
of the Rotor (31).
3. Stand the assembled Rotor and End Plate upright, grasping the
splined rotor hub with leather-covered or copper-covered vise jaws.
4. Place a Vane (32) in each vane slot in the Rotor.
5. Slide the Cylinder (33) down over the Rotor, aligning the holes in the
Cylinder with those in the Front End Plate.
6. Using a sleeve that will contact only the outer ring of the Rear Rotor
Bearing (29), press the bearing into the Rear End Plate (30).
7. Using a sleeve that will contact only the inner ring of the Rear Rotor
Bearing, press the assembled bearing and end plate onto the short
hub of the Rotor.
8. Before installing the Motor Assembly in the Motor Housing (1), be
certain that the Air Port Gaskets (16) and Gasket Retainers (17) are
in good condition and positioned with large open end down in the
recess in the Motor Housing.
9. Using a 3/16” x 8” rod, insert the rod through the Cylinder Dowel
Holes in both End Plates and Cylinder. This will hold all the motor
parts in alignment. Allow the 3/16” rod to protrude from the Front End
Plate far enough to enter the dowel hole at the bottom of the bore of
the Motor Housing.
10. Put the rod into the Dowel Hole in the Motor Housing, then slide the
assembled Motor into the Housing. Remove the rod and install the
Cylinder Dowel (28).
11. Place the Motor Clamp Washer (26) concave side first, over the hub
of the Rear End Plate so that the outer rim of the Washer contacts
the End Plate.
Assembly of the Reverse Valve
1. Dampen the Reverse Valve Seal (19) with O-ring lubricant and install
the Seal in the groove on the Reverse Valve Assembly (18).
2. Slide the Reverse Valve Assembly into the Motor Housing
Assembly (1).
3. Aligning the flats on the Reverse Lever (20) with those on the
Reverse Valve Assembly, slide the Reverse Lever on the Reverse
Valve Assembly. Place the Housing Cover Gasket (27) on the Motor
Housing.
4. Put the Reverse Lock Spring (24) followed by the Reverse Lock
Plunger (23) in the small hole at the bottom of the Housing Cover
Assembly (21).
5. Install the Motor Housing Cover (21). Tighten the Motor Housing
Cover Cap Screws to 10 to 12 ft-lb (14 to 16 Nm).
Assembly of the Impact Mechanism
(Dwg. TPD652)
1. Coat Hammers (39) with a light film of Ingersoll-Rand
Grease No. 170.
2. Replace Hammers in the Hammer Frame Assembly (37) exactly as
they were when you marked them prior to disassembly.
NOTICE
If you are installing new Hammers, or want to change
the location of the existing Hammers to utilize both
impacting surfaces, slide the Hammers in the Hammer
Frame so that the half-round notch on one Hammer is
located on one side of the Frame and the half-round
notch on the other Hammer is located on the other side
of the Frame.
Each Hammer is undercut on one side. When properly
installed in the Hammer Frame, these undercuts must
face each other.
3. Replace Hammer Pins (38).
4. Examine base of Anvil (40) and note its contour. While looking down
through Hammer Frame, swing the top Hammer to its full extreme
one way or other until you can match the contour of the Anvil. Put the
Anvil into the Hammer Frame and through the first Hammer. Swing
the bottom Hammer in opposite direction from the top Hammer and
maneuver Anvil slightly until it drops through the bottom Hammer.
Assembly of the Impactool
1. Secure Impactool in vise.
2. Set assembled hammer mechanism onto rotor shaft spline.
3. Place Hammer Case Gasket (36) over mechanism and against face
of Motor Housing.
4. Grease Anvil and top of Hammer Frame.
5. Reinstall the Hammer Case Assembly (41).
6. Assemble Dead Handle (44) to Dead Handle Bracket (43). Insert two
Hammer Case Cap Screws (45). Position assembly against
Hammer Case and thread the Screws into Housing.
7. Secure the Hammer Case Assembly with four Hammer Case Cap
Screws (45). Tighten to 20-25 ft-lb (27-34 Nm) torque.
8. Install a new Exhaust Silencer (5) in Motor Housing Assembly (1)
and install the Exhaust Deflector (4).
Cap Screw Specifications
Tighten the Hammer Case Cap Screws to a minimum of 20 ft-lb (27.1 Nm) torque.
Tighten the Housing Cover Cap Screws to a minimum of 10 ft-lb (13.5 Nm) torque.
TOP HAMMER
WIDE BEVEL UP
TOP HAMMER
HALF–ROUND NOTCH ON RIGHT
BOTTOM HAMMER
WIDE BEVEL DOWN
BOTTOM HAMMER
HALF–ROUND NOTCH ON LEFT