Aimco Lite-Touch Series Operating instructions

PO Box 16460, Portland, OR 97292-0460 z503-254-6600 zFax 503-255-2615
Lite-Touch Series
Pneumatic Screwdriver Repair Manual

Contents
Page
Number
1. Tools Needed for Repair 1
2. Pneumatic Screwdriver Repair Fixtures 2
3. Disassembly and Reassembly of the Clutch 3-4
4. Exploded View of the Clutch Assembly 5
5. Disassembly and Reassembly of the Gear Section 6
6. Exploded View of the Gear Casing Assembly
•US-LT30B-11 Series 7
•US-LT20B-18 7
•US-LT Series 8
7. Disassembly and Reassembly of the Air Motor Section 9
8. Exploded View of the Air Motor Assembly
•US-LT Push to Start Series 10
•US-LT Pistol Series 11
•US-LT Lever Series 12
9. Disassembly and Reassembly of the Angle Head Section 13
10. Exploded View of the Angle Head Assembly
•US-LT Series 14
11. LT Series Troubleshooting 15
12. Recommended Preventative Maintenance 16

October 2006 - 1-
Tools Needed for Repair
US-LT Drivers
1. Phillips Drivers (#1 & #2)
2. Dental Pick
3. Pin Spanners (#351)
4. Needle Nose Pliers
5. Pin Punch
6. Ball Peen Hammer (8 oz.)
7. Standard Pliers
8. Snap Ring Pliers
9. Crescent Wrench
10. Lock Ring & Horseshoe Washer Pliers (Proto-P250)
11. Propane Torch (Turner Self-Lighting)

October 2006 - 2-
Pneumatic Screwdriver Repair Fixtures
US-LT Series Jig List
Jig to Insert the Band on the Anvil
Part
Number
Model Number
471-670-7-1 US-LT Series
Jig to Hold Tool for Disassembly & Reassembly
Part
Numbers
Model Numbers
459-025-1-0 US-LT10 & US-LT20
408-025-1-0 US-LT30 & US-LT40
444-025-4-0 US-LT50

October 2006 - 3-
Disassembly and Reassembly of the Clutch
Disassembly
1. Separate the Clutch Casing from the Gear Casing and remove the Clutch Assembly.
2. Remove the Regulator Screw by inserting a Phillips Driver between it and the Retainer and turning the
Phillips Driver counter-clockwise.
3. Slide the Retainer off the Anvil. Make sure not to lose the Pin that locks the Retainer to the Anvil.
4. Remove the Torque Spring, Spring Setter, and Back-up Ring from the Anvil.
5. Carefully slide the Cam Ring up and remove the four Balls from under it. Now remove the Cam Ring.
6. Lift the hooked end of the Band out of the hole in the Anvil and slide it around the Anvil until the end of the
Notch Pin is exposed. Now remove the Notch Pin. Caution:Do not bend or stretch the Band out of shape.
7. Remove the Snap Ring from the back of the Anvil.
8. Slide the Anvil Spacer up and remove the Balls that hold the Cam in the Anvil. Note: “C” model clutches
do not have the Snap Ring, Anvil Spacer, or Balls.
9. Now slide the Cam and Pilot Pin out of the Anvil. Remove the Pilot Pin from the Cam.
10. Remove the Ball and Spring from out of the Anvil.
11. Thoroughly clean all parts.
Inspection
1. Cam: Inspect the Cam Lobes for grooving where they push the Ball out against the Cam Ring.
Pilot Pin: Inspect the shoulder that is pushed up against the Notch Pin for rounding.
Notch Pin:Inspect the ends for rounding.
Cam Ring:Inspect the inside surface where the Balls ride for pitting and grooving.
Balls: Inspect for pitting.
2. Inspect all Springs for tension.
3. Replace all worn parts.
Reassembly
1. Install the Pilot Pin into the Cam with the square end up.
2. Put the Spring and Ball into the Anvil and slide the Cam into the Anvil.
3. Line up the groove on the Cam with the hole in the Anvil and install all of the Balls that hold the Cam in
place.
4. Install the Anvil Spacer and Snap Ring. Note:Make sure the Anvil’s Spacer is installed the correct way.
Consult breakdown for the tool you are working with for proper installation.
5. Install the Notch Pin into the Anvil and slide the Band back into place. Now rotate the Cam and make sure
the Notch Pin is pushing the Band up.
6. Put a small amount of grease in each hole of the Anvil and install the Balls.

October 2006 - 4-
Disassembly and Reassembly of the Clutch(cont.)
7. Slide the Cam Ring down onto the Balls.
8. Put the Back-up Ring and Spring Retainer down onto the Cam.
9. Install the Torque Spring and Retainer onto the Anvil.
10. Line the slot in the Anvil with the slot in the Retainer and install the Locking Pin.
11. Thread the Regulator Screw onto the Anvil (counter-clockwise).
12. Install the Clutch back into the tool and test.

October 2006 - 5-
Exploded View of the Clutch Assembly
US-LT Series
Part
Number
Description
Part
Number
Description
1
3
4
5
6
7
8
9
10
11
12
13
14
15
Bushing
Clutch Casing Sleeve
O-Ring
Clutch Casing
Spring
Bit Sleeve
Regulator Screw
3/32 Steel Ball
Torque Spring
Back-up Ring
1/8 Steel Ball
Notch Pin
3/16 Steel Ball
“G” Pin
16
17
18
19
20
21
22
23
24
25
26
27
28
3/32 Steel Ball
Anvil Spacer
Snap Ring
Pin
Retainer
Spring Setter
Cam Ring
Bit Band
Anvil
Notch Pin Band
Spring
Pilot Pin
Cam

October 2006 - 6-
Disassembly and Reassembly of the Gear Section
Disassembly
1. Remove Gear Casing from the Air Motor Casing (right-hand thread).
2. Remove the Snap Ring from the front of the Gear Casing.
3. Remove the Planet Gears and the Gear Cage from the Gear Casing. In some Gear Casings, the Gear Cage
will come out the front of the Gear Casing.
4. Remove the Bearing from the Gear Casing.
5. Clean all parts thoroughly.
Inspection
1. Inspect the teeth of the Gear Casing and Planet Gears for pitting and grooving.
2. Inspect Needle Rollers for wear.
3. Inspect Bearings for side play and knocking.
4. Replace all worn parts.
Assembly
1. Install the Bearing and Snap Ring into the front of the Gear Casing. Note: Except for the US-LT20-18 &
US-LT30-17, proceed to step #6.
2. Install the Second Gear Cage into the Casing.
3. Install three Needle Rollers and the first set of Planet Gears. Put a small amount of grease by each Planet
Gear and on the Gear Cage.
4. Install the First Gear Cage, Needle Rollers, and the second set of Planet Gears. Put a small amount of
grease by each Planet Gear and on the Gear Cage. Note:On the mid and low RPMs, make sure to install
the Spacer.
5. If the tool you are working with has a Rotor Gear, install the Rotor Gear and Spacer into the Gear Cage.
6. On the US-LT30-17, install the Planet Gears and Needle Rollers into the Gear Cage. Now install the Gear
Cage into the Gear Casing through the front and install the Bearing and Snap Ring.
7. On the US-LT20-18, install the Internal Gear on the top of the Air Motor section and over the Rotor. Now
install the Planet Gears and Needle Roller into the Gear Cage. Make sure the timing marks and top of the
larger end are lined up opposite one another and install into the Internal Gear. Slide the Gear Casing down
over the Internal Gear and thread onto the Air Motor Casing.
8. Install the Gear Casing Assembly onto the Air Motor Casing and test the tool.

October 2006 - 7-
Exploded View of the Gear Casing Assembly
US-LT30B-11 Series US-LT20B-18
Part
Number
Description
Part
Number
Description
1
2
3
4
Gear Casing
Needle Roller
Planet Gear
Gear Cage
5
6
7
8
Ball Bearing
Spacer
Spacer
Internal Gear

October 2006 - 8-
Exploded View of the Gear Casing Assembly
US-LT Series
Part
Number
Description
Part
Number
Description
1
2
3
4
5
6
7
8
9
10
11
12
Snap Ring
Bearing
Spacer
Gear Casing
Planet Gear
Needle Roller
Planet Gear
Needle Roller
Spacer
First Gear Cage
Rotor Gear
Needle Roller
13
14
15
16
17
18
19
20
21
22
23
Needle Roller
Rotor Gear
Spacer
First Gear Cage
Second Gear Cage
Planet Gear
Planet Gear
Gear Cage
Planet Gear
Needle Roller
Spacer

October 2006 - 9-
Disassembly and Reassembly of the Air Motor Section
Disassembly
1. Remove the Air Motor Casing from the Gear Casing.
2. Taking hold of the end of the Rotor, pull the Air Motor out of the Casing.
3. Pull the Front Plate off and remove the Bearing.
4. Remove the Blades from the Rotor.
5. Press the Rotor out of the Rear Plate Bearing and remove the Bearing from the Rear Plate.
6. Thoroughly clean all parts.
Inspection
1. Inspect Bearings for knocking and side play.
2. Inspect Cylinder for waviness.
3. Inspect Plates for grooving.
4. Inspect Blades for splitting and grooving on the sides and ends.
5. Inspect the Exhaust Filter for dirt.
6. Replace all worn parts.
Assembly
1. Press greased Bearing into Rear Plate and over the Rotor. Note:There should be a slight drag between the
Rotor and the Rear Plate.
2. Lightly oil the Blades and install into the Rotor with the flat side out.
3. Slide Cylinder down over the Rotor, lining up the Roll Pin with the center hole in the Rear Plate.
4. Grease Bearing and press into the Front Plate. Install the Front Plate onto the Rotor with the Bearing side up.
5. Slide the Air Motor Assembly into the Casing, lining up the Roll Pin on the side of the Front Plate with the
slot in the Casing. Note:The Air Motor will stick out of the Casing about 1/16th of an inch.
6. Thread the Gear Casing Assembly onto the Air Motor Casing and test the tool.

October 2006 - 10 -
Exploded View of the Air Motor Assembly
US-LT Push to Start Series
Part
Number
Description
Part
Number
Description
1
2
3
4
5
6
7
8
9
10
11
12
Gear Casing
Bearing
Front Plate
Roll Pin
Spring
Reverse Valve
Reverse Valve Bushing
Pin
Valve Rod
Ball
Filter
Exhaust Deflector
13
14
15
16
17
18
19
20
21
22
23
Air Inlet Bushing
Spacer
Roll Pin
Rotor
Blade
Cylinder
Rear Plate
Bearing
Casing
O-Ring
Cone Spring

October 2006 - 11 -
Exploded View of the Air Motor Assembly(cont.)
US-LT Pistol Series
Part
Number
Description
Part
Number
Description
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Bearing
Front Plate
Blade
Roll Pin
Cylinder
Roll Pin
Bearing
Rear Plate Spacer
Valve Rod
Handle Bushing
Packing
Shut-off Valve
O-Ring
Handle Casing
Roll Pin
Rotor
Rear Plate
Valve Lever
Allen Head Dog Point Screw
Reverse Lever
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
Reverse Valve
Valve Rod Bushing
Pin
Roll Pin
Spring
Ball
Reverse Valve Bushing
O-Ring
Ball
Valve
Cone Spring
Inner Snap Ring
Exhaust Stack
Filter
O-Ring
Air Inlet Bushing
Pin
Pin
Handle Jacket

October 2006 - 12 -
Exploded View of the Air Motor Assembly(cont.)
US-LT Lever Series
Part
Number
Description
Part
Number
Description
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Ball Bearing
Roll Pin
Blades
Cylinder
Rear Motor Plate
Ball Bearing
Valve Rod
Rear Plate Spacer
Bushing
Rear Valve Rod
Reverse Lever
Spring
Reverse Valve Bushing
Pin
Roll Pin
Valve Pin
Valve Pin Bushing
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
Valve
Filter
Exhaust Deflector
Air Inlet Bushing
Front Motor Plate
Roll Pin
Rotor
Roll Pin
Valve Rod Cap
Casing
Shut Off Valve
Cone Spring
Valve Bushing
O-Ring
Valve Packing
Air Inlet Connector
Cone Spring

October 2006 - 13 -
Disassembly and Reassembly of the Angle Head Section
Disassembly
1. Loosen and remove the Angle Head Casing Cover, Driven Gear, and Driven Gear Spindle.
2. Loosen Locking Nut from the Clutch Casing and remove the Angle Head Casing.
3. Remove the Bearing from down inside the Angle Head Casing and remove the Driving Gear.
4. Thoroughly clean all parts.
Inspection
1. Inspect the Driven and Driving Gears for pitting and grooving.
2. Inspect all Bearings for side play and knocking.
3. Inspect the Driven Gear Spindle for side wear.
4. Replace all worn parts.
Assembly
1. Set the Driven Gear into the Angle Head Casing Cover and install the Balls around the Driven Gear.
2. Install the Driven Gear into the Angle Head Casing and secure by threading the Angle Head Casing Cover
into the Angle Head Casing.
3. Put a small amount of grease on the Driving Gear and install it into the Angle Head Casing.
4. Install the Adjusting Spacer and Bearing into the Angle Head Casing. Note:The Adjusting Spacer is used
to set the gear lash.
5. Install the Angle Head Casing onto the Clutch Casing and test the tool.

October 2006 - 14 -
Exploded View of the Angle Head Assembly
US-LT Series
Part
Number
Description
Part
Number
Description
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Angle Head Casing Cover
Adjusting Spacer
1/16 Steel Ball
1/8 Steel Ball
Driven Gear
Driven Gear Spindle
Round Plate
Angle Casing
Driving Gear
Needle Roller Bearing
Snap Ring
Adjusting Spacer
Ball Bearing
Bit Band
15
16
17
18
19
20
21
22
23
24
25
26
27
28
Needle Roller Bearing
Driven Gear
1/8 Steel Ball
Spring
Angle Head Casing Cover
Adjusting Spacer
1/16 Steel Ball
Spacer
Locking Nut
Snap Ring
Needle Roller Bearing
Clutch Casing Sleeve
O-Ring
Clutch Casing

October 2006 - 15 -
LT Series Troubleshooting
PROBLEM CAUSE SOLUTION
Loses torque every time the fastener is
run down. Finally the tool will not run.
The Lock Pin did not get put
back into the Spring Retainer.
Put the Lock Pin in the
Spring Retainer.
Tool operates intermittently.
One or more of the shoulders
on the Pilot Pin is rounded.
Replace the Pilot Pin.
Tool shuts off as soon as it is started or
tool shuts off but will not re-start.
Spring under Pilot Pin has
lost tension. Notch Pin is
rounded. Notch Pin Band is
stretched out of shape. The
shoulders on the Pilot Pin are
rounded.
Replace Notch Pin, Band,
and/or Pilot Pin. Replace
Spring.
Tool ratchets when it shuts off.
Valve Rod too long. Bur on
Pilot Pin or inside of Cam.
Shorten Valve Rod. Clean
bur off of Pilot Pin or Cam.
Loss of RPMs
Exhaust Filter is dirty causing
back pressure.
Replace Filter.
Lever type only. Tool will not run.
The Valve Rod is pushed
through the Shut-off Valve.
Replace Shut-off Valve.
Tool runs all the time.
O-ring has gotten pushed
down into the Casing. Air
pressure is too high.
Put the O-ring back into its
seat.
Lever type only. Tool will not reset.
Valve Packing damaged or
Valve Pin installed upside-
down.
Replace Valve Packing.
Reinstall Valve Pin right-
side-up.
The tool will not reset after it shuts off.
The Anvil Spacer is back-
wards.
Turn the Anvil Spacer over.
Pistol series only. Tool will not run.
The Valve Rod Cap Pin has
been pushed by the ball.
Reset the Valve Rod Cap.
Pistol series only. Tool runs all the time.
Foreign matter under ball in
Throttle assembly.
Clean Throttle assembly.

October 2006 - 16 -
Recommended Preventative Maintenance
It is recommended that the whole tool be cleaned and inspected every 250,000 cycles or six months, whichever
occurs first.

Corporate Headquarters
1204 E Maple Road 10000 SE Pine Street Ave. Morones Prieto 2110 Pte.
Troy, MI 48083 Portland, OR 97216 Col. Loma Larga
248-583-1180 800-852-1368 Monterrey, NL CP 64710, Mexico
FAX [phone] FAX [phone]
www.aimco-global.com FAX [phone]
LIT-MAN410
Rev. 08/2009
Printed in USA
©2009 AIMCO