Universal Air Tools UT8355-RL - Manual (Page 2)

Safety Rules When Using an Impact
Wrench
1) Read all the instructions before using this tool. All operators
must be fully trained in its use and aware of these safety rules.
All service and repair must be carried out by trained personnel.
2) The socket used must be of the correct drive size and the
"impact" type. Never use sockets other than impact type.
3) Do not use sockets with excessive wear to the input and
output drives. Check that the square on any other type of drive
or the impact wrench is not cracked or excessively worn before
fitting or changing socket, extension, etc. Make sure that the
socket is firmly fixed to the tool.
4) Always ensure that a stable position or footing is adopted
before using the tool.
5) Ensure that the tool has been correctly set up on a test joint.
Incorrect set up could cause joint breakage with sudden and
Dismantling & Assembly Instructions
Disconnect tool from the air supply.
Remove oil plug (3) with o-ring (2) and drain the oil contained in
the front end into a suitable container. Grip motor housing (1) in
a vice with soft jaws and remove 4 off capscrews and
lockwashers (31) and pull off steel housing (45). Remove o-ring
(44) and oil seal (46) and steel housing bushing (43) may be
pressed out of steel housing (45). Pull off anvil collar (42) and
anvil spacer (39) from anvil (38). Grip hammer cage (32) and pull
off the hammer assembly. Pull out anvil (38) and separate
hammer cage (32), cam release spring (37), 2 off hammer pins
(35), hammer cam (36), ball (34) and cam ball pilot (33).
Unscrew hose adaptor with screen (7) and remove exhaust
deflector (6), throttle spring (5) and valve stem (4). Remove 2 off
screws (13) and pull out trigger assembly. Before dismantling
the trigger assembly carefully note for reassembly the
orientation of trigger (12) to the slot/groove in the end of throttle
pin (8). When reassembling, the orientation of the trigger (12) to
this groove/slot is important so that the slot/groove locates
around the end of valve stem (4). Prise off trigger (12) from
throttle pin (8) and separate throttle pin (8), o-ring (2), 2 off
o-rings (9), throttle bushing (10) and stop cover (11). Remove 4
off screws with lock washers (31) and pull off end cap (26)
assembly. Remove ‘C’ ring (28) from air reverse valve (24) and
remove gasket (27). Pull out air reverse valve (24) from end cap
(26) being careful not to lose stop pin (30) and stop pin spring
(29). Tap the end of rotor (20) to drive the motor assembly out
of the rear end of motor housing (1). Pull off rear plate (22)
assembly and front plate (17) assembly from rotor (20) and
remove cylinder (18) and guide pin (21). Remove 6 off rotor
blades (19) from rotor (20). Tap out bearing (23) from rear plate
(22) and remove o-ring (16) and tap out bearing (14) and oil seal
(15) from front plate (17). Do not remove handle rubber (47)
from motor housing (1) unless a replacement is required. o-ring
(25) may be removed from air reverse valve (24). Remove
socket retaining ring (41) and o-ring (40) from anvil (38).
Reassembly
Clean all components and examine for wear and cracks, etc
before assembling. Look in particular for wear and cuts on o-
rings and oil seals. Check for wear and damage to rotor blades
(19) and particularly check for wear and cracks on hammer cage
(32), cam ball pilot (33), hammer pins (35), hammer cam (36)
and anvil (38) particularly in the area of the square drive. Before
reassembling the motor, first ensure that the faces of end plates
(17) and (22) that abut cylinder (18) are flat and free from
damage and burrs. If necessary lap on a flat, very find grade of
abrasive paper.
Lightly coat all parts with a pneumatic tool lubricating oil and
assemble in the reverse order. On completing assembly,
remove oil plug (3) with o-ring (2) and pour into the front end
one ounce (28cc) of an SAE grade 20 oil. Replace oil plug (3)
and o-ring (2). With trigger (12) depressed, pour into hose
adaptor (7) one teaspoonful (5ml) of a pneumatic tool lubricating
oil and release the trigger. Connect tool to a suitable air supply
and run tool slowly for a few seconds to allow the oil to
circulate. Reset for operation required - See Section Operating.
pneumatic motor lubricating oil preferably incorporating a rust
inhibitor. Reconnect tool to air supply and run tool slowly for a
few seconds to allow air to circulate the oil. If tool is used
frequently lubricate on daily basis and if tool starts to slow or
lose power. When lubricating, also ensure that screen(1) is
clean.
It is recommended that the air pressure at the tool whilst the
tool is running is 90 p.s.i./6.3 bar. The tool can run at lower and
higher pressures with the maximum permitted working air
pressure of 100 p.s.i./7.0 bar. For a lower air pressure the tool
will give a lower output for a given setting of the air regulator set
for 90 psi operation and an increased output for higher
pressures. Hence it is possible that changes in supply pressure
can give situations where the fastener is under or over
tightened. For changes in pressure, the regulator position and
application should be reassessed.
It is recommended that joint tightness of the threaded fastener
assembly be checked with suitable measuring equipment.
Page No 2
Operating
The output of the impact wrench in prime working condition is
governed by mainly three factors
a) the input air pressure
b) the time the impact wrench is operated on the joint. Normal
time for joints of average tension requirement 3 to 5 seconds
c) the setting of the air regulator for a given joint at a given
pressure operated for a given time.
The air regulator item (24) can be used to regulate the output of
the impact wrench if no other control means is available. It is
strongly recommended that an external pressure regulator
ideally as part of a filter/regulator/lubricator (FRL) is used to
control air inlet pressure so that the pressure can be set to help
control the tension required to be applied to the threaded
fastener joint.
There is no consistent reliable torque adjustment on an impact
wrench of this type. However, the air regulator can be used to
adjust torque to the approximate tightness of a known threaded
joint. To set the tool to the desired torque, select a nut or screw
of known tightness of the same size, thread pitch and thread
condition as those on the job. Turn air regulator to low position,
apply wrench to nut and gradually increase power (turn regulator
to admit more air) until nut moves slightly in the direction it was
originally set. The tool is now set to duplicate that tightness,
note regulator setting for future use. When tightening nuts not
requiring critical torque values, run nut up flush and then tighten
an additional one-quarter to one-half turn (slight additional
turning is necessary if gaskets are being clamped). For additional
power needed on disassembly work, turn regulator to its fully
open position. This impact wrench is rated a 3/4" bolt size.
Rating must be down graded for spring U bolts, tie bolts, long
cap screws, double depth nuts, badly rusted conditions and
spring fasteners as they absorb much of the impact power.
When possible, clamp or wedge the bolt to prevent spring back.
Soak rusted nuts in penetrating oil and break rust seal before
removing with impact wrench. If nut does not start to move in
three to five seconds use a larger size impact wrench. Do not
use impact wrench beyond rated capacity as this will drastically
reduce tool life.
NOTE: Actual torque on a fastener is directly related to joint
hardness, tool speed, condition of socket and the time the tool
is allowed to impact.
Use the simplest possible tool-to-socket hook up. Every
connection absorbs energy and reduces power.