Universal Air Tools UT8020T - Manual (Page 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 (15) 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 3/8" 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.
inlet bushing (10). Unscrew 2 off cap screws (49) and 2 off cap
screws (50) and remove together with 4 off lock washers (46)
to release housing cap (9) and gasket (27) from the assembly.
At this stage remove throttle lever (5) together with 2 off throttle
lever pins. Unless replacements are required do not extract 2 off
lever pins from throttle lever (5).
From housing cap assembly pull off 2 off plungers (26), remove
2 off plunger springs (25) and 2 off valve pins (24). It is then
possible to lever out 2 off valves (23) and 2 off springs (22)
taking care not to allow the spring to fly away.
Pull out motor pin (34) and extract the assembly comprising of
retaining ring (20), rear end plate (29), bearing (28), rotor (30),
6 off rotor blades (32) and cylinder (33). Note at this time the
way cylinder (33) is removed and note that it must be
reassembled in the same way with the chamfer on the outside
diameter to end face at the front end of the tool. Remove rotor
blades from rotor, take off retaining ring (20) and pull rotor
through rear end plate and bearing assembly. Using a suitable
punch bearing (28) may be removed from rear plate (29).
Pull out front end plate (35) complete with O-ring (36) and
carefully prise off the O-ring. Remove bearing (37) and seal (36)
from plate (35). Remove retaining ring (39) from motor housing
(1) and the complete hammer mechanism comprising of anvil
(44) complete with socket retainer (46) and O-ring (45), hammer
cage (40), hammer dog (42), cam (41) and hammer pin (43)
may be extracted from the motor housing (1). Socket retainer
(46) and O-ring (45) may be prised off of anvil (44).
Oil seal (3) may be hooked out of the front of motor housing and
anvil bushing (2) pressed out.
Reassembly
Examine all parts for wear and examine O-rings and seals for
signs of cuts or wear etc. Particularly examine anvil (44)
particularly around the square drive area, hammer dog (42) and
cam (41) for wear and cracks. Replace any part with those
supplied by the manufacturer or an authorised distributor.
Clean and lubricate all parts with a suitable pneumatic tool
lubricating oil and reassemble in the reverse order. On
completion of assembly check anvil will rotate and lever and
reverse valves operate freely. Remove plug (7) and O-ring (8)
and inject approx. 1/2 ounce (15cc) of a SAE10 or 20 oil.
Replace plug and O-ring. Inject approx. 5ml of a suitable
pneumatic tool lubricating oil (preferably incorporating a rust
inhibitor) into the tool via air inlet bushing (10). Connect tool to
a suitable air supply, run tool slowly for a few seconds to allow
oil to circulate and reset for operation. See section "Operating".
pressing the trigger on the tool. Disconnect the air line and pour
into the intake bushing a teaspoonful (5ml) of a suitable
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.
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.
Page No 2
Dismantling & Assembly Instructions
Disconnect tool from air supply.
Remove plug (7) and O-ring (8) and invert tool and drain oil from
front end into a suitable receptacle. Grip tool in vice locating on
the square drive of anvil (44). Unscrew 2 off screws (19) and
retainer plate (17). Pull out air regulator (15) complete with O-
ring (12). O-rings (11) and (12) may be removed from stem of
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
unexpected movement of the tool.
6) Use only correct spare parts for repair.
7) Always ensure that the reverse valve is in the correct position
before operating the tool. Do not run the tool unless the socket
is first located on the joint.
8) Check hose and fittings regularly for wear. Use quick connect