Power Fist 8344137 User manual

User Manual
8344137
3/8 in. dr
Butterfly Air
Impact Wrench
V 2.7
Please read and understand all instructions before use.
Retain this manual for future reference.

3
8344137V 2.7
Visit www.princessauto.com for more information
8344137
3/8 in. dr
Buttery Air
Impact Wrench
V 2.7
SPECIFICATIONS
Max Pressure 100 PSI
Max Torque 75 ft-lb
Drive 3/8 in.
No Load Speed 11,000 RPM
Air Consumption 4 CFM @ 90 PSI
Air Inlet 1/4 in. NPT
Recommended Hose Size 3/8 in.
Working Torque 75 ft-lb
Hammer Mechanism Rocking Dog
Housing Material Aluminum
The actual torque delivered at each setting will depend on the air pressure supplied to the tool. Test
the actual torque by tightening a nut or bolt at each setting then observing the resultant torque with a
mechanical torque wrench (not included).

3/8 in. dr Butterfly Air Impact Wrench
4For technical questions call: 1-800-665-8685
8344137V 2.7
IMPORTANT SAFETY PRECAUTIONS
WARNING! Read and understand all instructions before using this tool. The operator must follow basic
precautions to reduce the risk of personal injury and / or damage to the equipment. Before allowing
someone else to use this tool, make sure they are aware of all safety information.
WARNING! The warnings, cautions and instructions discussed in this instruction manual cannot cover
all possible conditions and situations that may occur. Common sense and caution are factors that
cannot be built into this product, but must be supplied by the operator.
NOTE: Keep this manual for the safety warnings, precautions and operating, inspection and maintenance
instructions. When this manual refers to a part number, it refers to the included parts list.
WORK AREA
1. Operate in a safe work environment. Keep your work area clean and well lit.
2. Do not use in the presence of flammable gases or liquids.
3. Keep anyone not wearing the appropriate safety equipment away from the work area.
NOTE: Minimize distractions in the work environment. Distractions can cause you to lose control of
the tool.
4. Always lock up tools and keep them out of the reach of children.

3/8 in. dr Butterfly Air Impact Wrench
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8344137 V 2.7
PERSONAL SAFETY
CAUTION! Wear protective equipment approved by the Canadian Standards Association (CSA) or
American National Standards Institute (ANSI) when using the butterfly air impact wrench.
1. Dress properly, wear protective equipment. Use breathing, ear, eye, face, foot, hand, and head
protection. Always wear ANSI approved impact safety goggles, which must provide both frontal
and side protection. Protect your hands with suitable gloves. Protect your head from falling
objects by wearing a hard hat. Wear an ANSI approved dust mask or respirator when working
around metal, wood and chemical dusts and mists. Wear ANSI approved earplugs. Protective,
electrically non-conductive clothes and non-skid footwear are recommended when working.
Wear steel-toed boots to prevent injury from falling objects.
2. Control the tool, personal movement and the work environment to avoid personal injury or
damage to the tool. Stay alert, watch what you are doing and use your common sense.
a. Keep articles of clothing, jewelry, hair, etc., away from moving parts to avoid entanglement
with a tool.
b. Do not operate any machine / tool when tired or under the influence of drugs,
alcohol or medications.
c. Do not overreach when operating a tool. Proper footing and balance enables better control
of a tool in unexpected situations.
SPECIFIC SAFETY PRECAUTIONS
1. Do not over-tighten nuts. They could shatter and cause damage to the tool or work piece or
cause injury. Use a torque wrench to torque the nut after using the impact wrench.
2. Do not use any additional force upon the impact wrench in order to remove a nut.
3. Do not allow the impact wrench to run without load for an extended period of time, as this will
shorten its life.
4. This tool will not stop moving immediately. Do not lay the tool down or leave it unattended
until it has come to a complete stop. A part that is moving could make the tool jump or grab a
surface and pull the tool out of your control.

3/8 in. dr Butterfly Air Impact Wrench
6For technical questions call: 1-800-665-8685
8344137V 2.7
VIBRATION PRECAUTIONS
This tool vibrates during use. Repeated or long-term exposure to vibration may cause temporary or
permanent physical injury, particularly to the hands, arms and shoulders.
1. Anyone using vibrating tools regularly or for an extended period should first be examined by
a doctor and then have regular medical checkups to ensure medial problems are not being
caused by or worsened from tool use. Pregnant women or people who have impaired blood
circulation to the hands, past hand injuries, nervous system disorders, diabetes or Raynaud’s
Disease should not use this tool. If you feel any medical symptoms related to vibrations (such
as tingling, numbness, and white or blue fingers), seek medical attention as soon as possible.
2. Do not smoke during use. Nicotine reduces the blood flow to the hands and fingers, increasing
the risk of vibration-related injury.
3. Wear suitable gloves to reduce the vibration effects on the user.
4. Use tools with the lowest amount of vibration when there is a choice between
different processes.
5. Do not use for extended periods. Take frequent breaks when using this tool.
6. Let the tool do the work. Grip the tool as lightly as possible (while still keeping safe
control of it).
7. To reduce vibrations, maintain the tool as explained in this manual. If abnormal vibrations
occur, stop using this tool immediately.
TOOL USE AND CARE
WARNING! Do not use the tool if the trigger does not function properly. Any tool that cannot be
controlled with the ON / OFF switch is dangerous and must be repaired.
1. Use the correct tool for the job. Maximize tool performance and safety by using the tool for its
intended task.
2. Do not modify this tool or use for a purpose for which it was not designed.
3. This tool was designed for a specific function.
Do Not:
a. Modify or alter the butterfly air impact wrench; all parts and accessories are designed with
built-it safety features that may be compromised if altered.
b. Use the butterfly air impact wrench in a way for which it was not designed.
4. Avoid unintentional starts. Be sure the trigger is in the off position when not in use and before
connecting it to any air source.
5. Only use the lubricants supplied with the tool or specified by the manufacturer. Other lubricants
may not be suitable and may damage the tool or even make the tool explode.
6. When not in use for an extended period, apply a thin coat of lubricant to the steel parts
to avoid rust.
7. Maintain the label and nameplate on the tool. These carry important information. If unreadable
or missing, contact Princess Auto for a replacement.

3/8 in. dr Butterfly Air Impact Wrench
7
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8344137 V 2.7
AIR COMPRESSOR
Ensure the compressor used with the butterfly air impact wrench can supply the required Cubic Feet per
Minute at the required PSI (see Specifications).
1. Use proper size and type of air pressure line
and fittings
2. Use only clean, dry, regulated compressed
air at the rated range as marked on the tool.
CAUTION! Do not use an air source besides
an air compressor to power this tool.
3. Always use an air regulator, an in-line filter
and a moisture trap in your compressed
air system. These accessories will increase
the tool’s life and keeps the tool in good
working condition. See the diagram for
recommended components of an airline.
4. Avoid using an air hose that is too long. The
longer the hose, the lower the pressure that
reaches the tool, possibly causing it to cease
functioning. As well, a longer hose can become a tripping hazard.
5. Air Tool CFM consumption ratings are based upon a 25% duty cycle. If you require continuous
duty, a larger compressor may be required. See Specifications for the tool’s continuous
duty limit.
AIR SOURCE INSTALLATION
WARNING! Never use pure oxygen, carbon dioxide, combustible gases or any bottled gas as an air
source for a tool. Such gases are capable of causing an explosion and serious injury to persons.
1. Set the air pressure regulator on the air compressor to 90 PSI. Do not exceed the butterfly air
impact wrench’s recommended air pressure. Excess pressure could result in damage to the tool
or serious personal injury.
2. Prepare a standard 1/4 in. air connector for use with your tool. Wrap the threaded portion of
the air connector with thread seal tape. Wrap in a clockwise direction so it will not unravel when
attaching to a quick connector. Attach it to the butterfly air impact wrench’s air inlet and tighten.
3. Attach a standard quick connector to the air source’s hose. Attach the air hose to the tool’s
air connector.
4. Check the air line and its connections for air leaks. Do not use the butterfly air impact wrench
until you have repaired all air leaks.

3/8 in. dr Butterfly Air Impact Wrench
8For technical questions call: 1-800-665-8685
8344137V 2.7
DISCONNECTING AIR SOURCE
WARNING! Failure to follow these steps could result in severe injury, tool or property damage.
Disconnect the butterfly air impact wrench from the air source before cleaning, servicing, changing parts /
accessories or when not in use.
1. Turn the air regulator to the OFF or L position.
2. Turn off the air compressor.
3. Disconnect the air pressure hose.
4. Discharge any residual pressure inside the butterfly air impact wrench.
LUBRICATION
1. It is very important that the tool be properly lubricated. Without proper lubrication, the tool will
not work properly and parts will wear prematurely. Manually dropping a drop or two of air tool
oil once a day into the tool’s male connector is better than using an automatic in-line lubricator,
which should only be required when there are multiple users of the same tool.
2. Keep the air line lubricator filled and correctly adjusted. The in-line lubricator should be
regularly checked and filled with air tool oil. Proper adjustment of the in-line lubricator is
performed by placing a sheet of paper next to the exhaust ports and holding the throttle open
approximately 30 seconds. The lubricator is properly set when a light stain of oil collects on the
paper. Excessive amounts of oil should be avoided.
3. Air tool oil is the only recommended lubricant for use in all air tools. Do not try to use other
types of lubricants to oil your tools. Using the wrong lubricant will cause premature tool
failure and / or loss of power. Use only recommended lubricants, specially made for pneumatic
applications. Substitutes may harm the rubber compounds in the tool’s O-rings and other
rubber parts.
4. Oiling your air tool regularly is important, but it is also important not to over oil your air tool.
Over oiling can cause premature tool failure. Your tool may not be ruined, but it will begin to
experience loss of power that will continually get worse until it no longer works. The tool then
has to be taken apart and cleaned of excess oil.
5. All air tools are packed in grease to prevent corrosion of internal parts during shipping and
storage. We recommend you clean this out to have optimum performance from your new air
tool. Add a generous amount of air tool oil in the air inlet, and then run the tool under no load
until exhaust is clear to remove packing grease. To maintain, add only one or two drops daily or
every 6 to 8 hours of use.
6. In the event that it becomes necessary to store the tool for an extended period of time
(overnight, weekend, etc.), it should receive a generous amount of lubrication at that time.
The tool should be run for approximately 30 seconds to ensure oil has been evenly distributed
throughout the tool. The tool should be stored in a clean and dry environment.
WARNING! Never use penetrating oil to clean or lubricate your air tool. Penetrating oils are a solvent
that will break down the internal grease and cause the air tool to seize up.

3/8 in. dr Butterfly Air Impact Wrench
9
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8344137 V 2.7
UNPACKING
1. Carefully remove the butterfly air impact wrench from the package.
a. Retain packing material until you have carefully inspected and satisfactorily installed or
operated the butterfly air impact wrench.
2. Make sure that all items in the parts list are included.
3. Inspect the parts carefully to make sure the butterfly air impact wrench was not damaged
while shipping.
PARTS IDENTIFICATION
OPERATION
SOCKET INSTALLATION
Turn off the air compressor and disconnect the air hose when changing sockets. After attaching the
socket, attach the air hose and turn the air compressor on.
The working torque of the butterfly air impact wrench is 75 ft-lb, make sure that the nut or bolt you
are using the tool to tighten can withstand the rated torque and is rated for 11,000 RPM or greater. If
available, check the recommended torque specifications for the nut or bolt.
1. Select the appropriately sized 3/8 in. drive impact socket for the job. Push and snap the socket
onto the anvil. Only use impact sockets that are specifically designed for use with an impact
wrench. Do not use worn or damaged sockets.
2. Push and snap the socket (not included) onto the anvil.
A Reverse
B Forward
C Throttle Lever "Butterfly"

3/8 in. dr Butterfly Air Impact Wrench
10 For technical questions call: 1-800-665-8685
8344137V 2.7
OPERATION
WARNING! This tool generates considerable torque when in use. Always hold the tool with both hands
when using, and brace yourself to resist the torque which will be delivered to the work piece.
1. Tighten the nut as far as you can by hand before using the butterfly air impact wrench.
2. Connect the butterfly air impact wrench to the air hose.
3. Place the socket on the nut and grip the butterfly air impact wrench tightly with both hands.
Press the trigger to start the tool.
NOTE: If the tool stalls while tightening, do not raise the outlet pressure of the air compressor
above 100 PSI.
4. Set the reverse lever so that the anvil turns clockwise (forward.)
5. Place the socket over the fastener, grip the butterfly air impact wrench firmly with both hands
and gently squeeze the trigger.
6. Turn the air regulator in the direction indicated by the H arrow on the regulator to increase the
power to the trigger.
NOTE: If the impact wrench does not tighten the fastener to your satisfaction, do not raise the
air pressure on the compressor over 100 PSI. Pressure above 100 PSI will strip the work piece
and damage the tool, potentially causing tool failure and serious injury. Use other appropriate
methods and tools to tighten the nut.
7. When the fastener is tightened, release the trigger and remove the tool and socket.
8. Use a mechanical torque wrench to check the fastener torque.
9. To loosen, set the reverse lever so that the anvil turns counterclockwise (reverse.)
10. When finished with the tool, turn off the air compressor, disconnect the air hose and discharge
any residual air remaining in the tool. Put the butterfly air impact wrench away in a storage area.

3/8 in. dr Butterfly Air Impact Wrench
11
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8344137 V 2.7
MAINTENANCE
WARNING! Disconnect the butterfly air impact wrench from the air supply before changing
accessories, servicing or performing maintenance. Replace or repair damaged parts. Use genuine
parts only. Non-authorized parts may be dangerous.
1. Check for damaged parts. Before using any tool, any part that appears to be damaged should
be carefully checked to determine that it would operate properly and perform its intended
functions. Check for alignment and binding of moving parts, for broken parts or mounting
fixtures, or for any other condition that may affect proper operation. Any part that is damaged
should be repaired or replaced by a qualified technician.
2. When servicing, use only identical replacement parts. Only use accessories intended for use
with this tool. Replace damaged parts immediately.
3. Keep the tool clean. Wipe the tool with a clean cloth and periodically blow out all areas with
compressed air. If compressed air is not available, use a brush to remove dust from all areas.
Do not use harsh chemicals or solvents to clean the tool.
4. Regularly inspect all mountings and screws to ensure tightness. Should any screws become
loose, tighten immediately.
5. If repairs are required, bring your tool to an authorized service center.
6. Wipe the butterfly air impact wrench down with a lint free cloth after each use.
7. Make sure the anvil is clear of dirt or debris. If possible, spray it with compressed air before and
after each use.
8. If an inline oil / filter system is not used; lubricate the tool daily or every 6 to 8 hours of use by
holding it so that the air inlet is facing up. Squeeze the trigger and place one or two drops of air
tool oil into the air inlet or remove the oiler screw and drop one or two drop of air tool oil into
the oiler spout. Squeezing the trigger allows the oil to circulate in the motor.
STORAGE
In the event that it becomes necessary to store the tool for an extended period of time (overnight,
weekend, etc.), it should receive a generous amount of lubrication at that time. The tool should be run for
approximately 30 seconds to ensure oil has been evenly distributed throughout the tool. The tool should
be stored in a clean and dry environment.
DISPOSING OF THE TOOL
If your butterfly air impact wrench has become damaged beyond repair, do not throw it out. Take it to the
appropriate recycling facility.

3/8 in. dr Butterfly Air Impact Wrench
12 For technical questions call: 1-800-665-8685
8344137V 2.7
TROUBLE SHOOTING
Problem(s) Possible Cause(s) Suggested Solution(s)
Tool runs at normal
speed but loses power
under load.
Motor parts worn. Have a qualified technician replace
worn parts.
Tool runs slowly.
Air flows slightly
from exhaust.
Motor parts jammed with
dirt particles. 1.Check air inlet filter for blockage.
2.Pour air tool lubricating oil into the air
inlet as per instructions.
3. Operate the tool in short bursts quickly
reversing rotation back and forth
where applicable.
4. Repeat above as needed. If this fails,
return to service center.
Air flow blocked by dirt.
Tool will not run.
Air flows freely
from exhaust.
O-rings throttle dislodged
from seat inlet valve. 1. Pour air tool lubricating oil into air inlet as
per instructions.
2. Operate the tool in short bursts of forward
and / or reverse rotation where applicable.
3. Tap the motor housing gently with a
plastic mallet.
4. Disconnect the air supply. Free the motor
by rotating the drive shank manually
where applicable.
5. If the tool remains jammed, return to
service center.
Tool will not shut off. O-rings throttle valve
dislodged from seat
inlet valve.
Have a qualified technician
replacethe O-ring.
Loss of power or
erratic performance.
Excessive drain on the air
line. Moisture or restriction
in the air hose. Incorrect size
or type of hose connectors.
Check the air supply. If the tool is
not connected to the air line,
connect it properly.
Tool runs at normal
sped but loses power
under load.
Cam clutch is worn due to
lack of lubricant.
1. Lubricate the clutch housing.
2. Check for excess clutch oil. Overfilling can
cause drag on high speed clutch parts.
Grease lubricated note: Heat usually indicates
insufficient grease in chamber. Severe
operating conditions may require more
frequent lubrication.
NOTE: A qualified person should carry out repairs.

3/8 in. dr Butterfly Air Impact Wrench
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8344137 V 2.7
PARTS BREAKDOWN

3/8 in. dr Butterfly Air Impact Wrench
14 For technical questions call: 1-800-665-8685
8344137V 2.7
Part No. Description Qty.
1 Motor Housing 1
2 Anvil Bushing 1
3 Oil Seal 1
4 Rubber Nose Guard 1
5 Throttle Lever 1
6 Throttle Pin 2
7 Oiler Screw 1
8 O-Ring 1
9 Back Cap 1
10 Air Inlet Block 1
11 O-Ring 1
12 O-Ring 2
13 Regulator 1
14 O-Ring 1
15 Retainer Plate 1
16 Screw 2
17 Fixing Ring 1
18 Retaining Ring 1
19 Valve Spring 2
20 Valve Seat 2
21 Valve 2
22 Plunger Spring 2
23 Plunger 2
Part No. Description Qty.
24 Back Cap Gasket 1
25 Ball Bearing 1
26 Rear End Plate 1
27 Rotor 1
28 Rotor Blade 6
29 Cylinder 1
30 Motor Pin 1
31 Front End Plate 1
32 Oil Seal 1
33 Ball Bearing 1
34 O-Ring 1
35 Snap Ring 1
36 Hammer Cage 1
37 Cam 1
38 Hammer 1
39 Hammer Pin 1
40 Anvil 1
41 O-Ring 1
42 Socket Retaining Ring 1
43 Cap Screw – Long 4
PARTS LIST

3/8 in. dr Butterfly Air Impact Wrench
15
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8344137 V 2.7

8344137
Manuel d'utilisateur
Vous devez lire et comprendre toutes les instructions avant d'utiliser l'appareil.
Conservez ce manuel afin de pouvoir le consulter plus tard.
V 2,7
Clé à chocs croisée
pneumatique à
prise de 3/8 po

3Visitez www.princessauto.com pour plus d'informations
8344137V 2,7
Clé à chocs croisée
pneumatique à
prise de 3/8 po
SPÉCIFICATIONS
Pression max. 100 lb/po carré
Couple max. 75 pi-lb
Prise 3/8 po
Vitesse à vide 11 000 tr/min
Consommation d’air 4 pi cubes/min à 90 lb/po carré
Entrée d’air 1/4 po NPT
Taille de tuyau recommandée 3/8 po
Couple de travail 75 pi-lb
Mécanisme de frappe Basculant
Matériau du boîtier Aluminium
Le couple réel obtenu à chaque réglage dépend de la pression d’air que reçoit l’outil. Vérifiez le couple
réel en serrant un écrou ou un boulon à chaque niveau de réglage. Ensuite, vérifiez le couple obtenu à
l’aide d’une clé dynamométrique mécanique (non comprise).

Clé à chocs croisée pneumatique à prise de 3/8 po
4En cas de questions techniques, appelez le 1-800-665-8685
8344137
V 2,7
CONSIGNES DE SÉCURITÉ IMPORTANTES
AVERTISSEMENT ! Veuillez lire et comprendre toutes les instructions avant d’utiliser cet outil.
L’utilisateur doit respecter les précautions de base lorsqu’il utilise cet outil afin de réduire le risque
de blessure et/ou de dommage à l’équipement. Avant de permettre à un autre individu d’utiliser cet
outil, assurez-vous qu’il est avisé de toutes les consignes de sécurité.
AVERTISSEMENT ! Les avertissements, les mises en garde et les instructions mentionnés dans ce
manuel d’instructions ne peuvent couvrir toutes les conditions et situations pouvant se produire.
L’opérateur doit faire preuve de bon sens et prendre toutes les précautions nécessaires afin d’utiliser
l’outil en toute sécurité.
REMARQUE : Conservez ce manuel qui contient les avertissements de sécurité, les précautions et les
instructions de fonctionnement, d’inspection et d’entretien. Lorsque ce manuel fait référence à un numéro
de pièce, il fait référence à la liste de pièces comprise.
AIRE DE TRAVAIL
1. Travaillez dans un environnement de travail sécuritaire. Gardez votre aire de travail propre et
bien éclairée.
2. N’utilisez pas d’outils en présence de gaz ou de liquides inflammables.
3. Assurez-vous que les personnes qui ne portent pas l’équipement de sécurité approprié ne se
trouvent pas à proximité de l’aire de travail.
REMARQUE : Minimisez les distractions au sein de l’environnement de travail. Les distractions
peuvent causer une perte de contrôle de l’outil.
4. Gardez toujours les outils dans un endroit verrouillé et hors de la portée des enfants.