Fairmont 48755 User manual

99924650 REV 4 © 2006 GreenleeTextron Inc. 11/06
H8508
Impact Wrench
Model 48755 (Serial Code FWN)
Model 48760 (Serial Code FWP)
SERVICE MANUAL
Read and understand all of the instructions and
safety information in this manual before operating
or servicing this tool.

H8508 Impact Wrench
Greenlee / A Textron Company 24455 Boeing Dr. • Rockford, IL 61109-2988 USA • 815-397-7070
Table of Contents
Safety ............................................................................. 2
Purpose .......................................................................... 2
Other Publications.......................................................... 2
Important Safety Information ......................................3-4
Disassembly ................................................................5-6
Inspection....................................................................... 6
Assembly.....................................................................7-8
Illustrations and Parts List .........................................9-13
Accessories .................................................................. 14
KEEP THIS MANUAL
Purpose
This manual is intended to familiarize all personnel
with the safe service procedures for the following
Fairmont tools:
48755 (Serial Code FWN)
48760 (Serial Code FWP)
Keep this manual available to all personnel.
Replacement manuals are available upon request
at no charge.
Safety
Safety is essential in the use and maintenance of
Fairmont tools and equipment. This manual and any
markings on the tool provide information for avoiding
hazards and unsafe practices related to the use of this
tool. Observe all of the safety information provided.
Other Publications
Operation Manual: Publication 99930269
Specications and Parts Manual: Publication 99930293
SAE Standard J1273 (Hose and Hose Assemblies):
Publication 99930323
All specications are nominal and may change as design improve-
ments occur. Greenlee Textron Inc. shall not be liable for damages
resulting from misapplication or misuse of its products.
Loctite is a registered trademark of Loctite Corporation.

Greenlee / A Textron Company 34455 Boeing Dr. • Rockford, IL 61109-2988 USA • 815-397-7070
H8508 Impact Wrench
This symbol is used to call your attention to hazards
or unsafe practices which could result in an injury
or property damage. The signal word, dened below,
indicates the severity of the hazard. The message
after the signal word provides information for
preventing or avoiding the hazard.
Hazards or unsafe practices which, if not avoided,
MAY result in injury or property damage.
Hazards which, if not avoided, COULD result in
severe injury or death.
Immediate hazards which, if not avoided, WILL
result in severe injury or death.
SAFETY
ALERT
SYMBOL
IMPORTANT SAFETY INFORMATION
Before operating this tool, see the safety information
and operating instructions in the Operation Manual.
Wear eye protection when operating
or servicing this tool.
Failure to wear eye protection could
result in serious eye injury from
ying debris or hydraulic oil.
Skin injection hazard:
Oil under pressure easily punctures
skin causing serious injury, gangrene
or death. If you are injured by
escaping oil, seek medical attention
immediately.
• Do not use ngers or hands to
check for leaks.
• Do not hold hose or couplers
while operating the power source.
• Depressurize the hydraulic system
before servicing.
Tool and accessory may be hot
during and after operation.
Contact with hot surfaces could
result in serious injury.

H8508 Impact Wrench
Greenlee / A Textron Company 44455 Boeing Dr. • Rockford, IL 61109-2988 USA • 815-397-7070
IMPORTANT SAFETY INFORMATION
Do not disconnect tool, hoses, or ttings while
the tool is running or if the hydraulic uid is
hot. Hot hydraulic uid could cause serious burns.
Do not exceed the maximum hydraulic ow,
pressure relief or back pressure listed in the
Specications and Parts manual.
Failure to observe this warning could result in
severe injury or death.
Do not reverse hydraulic ow. Operation with
hydraulic ow reversed can cause tool malfunc-
tion. Connect the supply (pressure) hose and
return (tank) hose to the proper tool ports.
Failure to observe this warning could result in
severe injury or death.
Procedure for disconnecting hydraulic hoses, ttings
or components:
1. Move the ow lever on the hydraulic power
source to the OFF position.
2. Stop the power source.
3. Follow the sequence under Disconnecting
Hoses to prevent pressure buildup. In case
some pressure has built up, loosen hoses,
ttings or components slowly.

Greenlee / A Textron Company 54455 Boeing Dr. • Rockford, IL 61109-2988 USA • 815-397-7070
H8508 Impact Wrench
Complete disassembly of the tool is not recommended.
If a complete overhaul is necessary, return the tool to
your nearest Fairmont Authorized Service Center.
The disassembly procedure is divided into sections of
the tool. Disassemble only the section(s) necessary to
complete the repair.
Disassemble the tool on a at, clean surface. Take care
not to lose or damage any parts that may fall free during
disassembly.
In order to simplify the disassembly and assembly
instructions, see the Tool Orientation illustration to iden-
tify the sides and ends of the tool.
Quick-Change Chuck (48755 Only)
1. Remove adapter (61) from retaining sleeve (50).
Note: To prevent the loss of any steel balls, perform
the next step over a clean, empty container.
2. Slide the thrust ring (52) back to expose thrust ring
lock (51). Remove thrust ring lock, thrust ring, and
spring (53). Slide the retaining sleeve off of the anvil
(49) and remove two steel balls (54).
Hammer Case Components
1. Using a wrench on the ats of the hammer case cap
(55), unscrew and remove the cap.
2. Remove the anvil (49), hammer frame (46), hammer
(47) and hammer pin (48).
3. Remove spacer (45), thrust bearing (43) and thrust
washers (44) from hammer case cavity.
Motor
1. Remove cap screws (16) and remove motor cap (6)
from handle (1). Remove gasket (15). Remove dowel
pins (14).
2. Pull idler shaft (13) with gear (10) from handle.
Remove gear from idler shaft. Remove the drive pin
(12) and retaining clip (11) from idler shaft.
3. Remove retaining ring (11), gear (10) and Woodruff
key (9) from drive shaft (8). Push drive shaft toward
hammer case end and remove it from the handle.
Trigger and Super Spool™
1. Remove roll pin (42) from trigger spool (29) by press-
ing or tapping it out with a hammer and punch.
Note: Support trigger (41) to prevent bending the
trigger spool (29).
2. Remove washer (39), spring (38), retaining ring (37),
and washer (36). Push the trigger spool (29) out of
the handle (toward the front of the tool).
3. Remove the retaining ring (33).
Note: Perform Step 4 over an empty container to
catch the steel ball (32) when it falls free.
4. Remove Super Spool™ (31) and O-ring (34).
Reversing Spool
1. Loosen and remove cap (24) on left side of tool and
pull the reversing spool (19) out the right side of tool.
Note: Attempting to push the reversing spool the
opposite way through the bore will damage the
O-rings and could allow particles of O-ring to get
into the motor.
2. Remove plug (22), spring (21) and poppet (20).
3. Repeat Step 2 for the right side of reversing spool (19).
Front End
(Hammer Case End)
Left Side Right Side
C
O
Back End
(Motor Cap End)
Disassembly

H8508 Impact Wrench
Greenlee / A Textron Company 64455 Boeing Dr. • Rockford, IL 61109-2988 USA • 815-397-7070
Inspection
Clean all parts with solvent and dry them thoroughly.
Inspect each component as described in this section.
Replace any component that shows wear or damage.
1. Bearings: Insert shaft into bearing. Spin shaft.
If shaft does not spin smoothly, replace the entire
assembly with the bearings already pressed in.
2. Motor cap and handle: Inspect mating surfaces,
gear cavities, oil passageways, etc. for grooves or
nicks. If any component shows wear or damage,
replace the entire assembly with the bearings
already pressed in.
3. Thrust rings: Replace any thrust ring that is
out-of-round or has been sprung.
4. Bearing (inside hammer case cap): Slide the anvil
into the bearing. Spin the anvil. If the anvil does
not turn smoothly, inspect the bearing surface.
If the bearing surface shows uneven wear, replace
hammer case cap as an assembly with the bearing
already pressed in.
5. Thrust bearing and thrust washers: Spin the bear-
ing against the washers. If bearing does not spin
smoothly, replace the bearing and washers.
6. Flow control cartridge: Inspect for cracks, grooves
or nicks. Replace the entire cartridge if it shows
wear or damage.
Disassembly (cont’d)
Flow Control Cartridge
1. Remove the retaining ring (66). Remove the ow
control cartridge from the handle.
2. Remove the O-rings (64, 65) from the cartridge.
Adjustable Torque Output Screw
1. Remove roll pin (70) from handle. Twist the adjust-
able torque screw (67) counterclockwise to remove
it from the handle.
2. Remove the O-ring (68) and backup ring (69) from
the screw.
Do not attempt to repair the ow control cartridge.
It contains no replaceable parts.
Failure to observe this warning could result in
severe injury or death.
Do not attempt to repair the ow control cartridge.
It contains no replaceable parts.
Failure to observe this warning could result in
severe injury or death.
7. Adjustable torque output screw: Inspect all surfaces
and all threads for cracks, grooves or nicks.
Replace if it shows wear or damage.
8. Inspect all other disassembled components for
cracks, grooves, or nicks.

Greenlee / A Textron Company 74455 Boeing Dr. • Rockford, IL 61109-2988 USA • 815-397-7070
H8508 Impact Wrench
Reversing Spool
1. Install a new O-ring (25) onto reversing spool (19).
Install a new O-ring (26) into the handle. Install a
new O-rings (30) on both plugs (22).
2. Install one poppet (20), spring (21) and plug (22) on
the left end (the end closest to the O-ring installed
on the spool in Step 1) of the spool. Secure assem-
bly with cap (24).
3. Slide the reversing spool assembly into the handle
from the right side.
4. Install poppet (20), spring (21) and plug (22) into
opposite end of spool. Secure with cap (24).
Use one wrench one each cap and tighten to
31 Nm (23 ft-lb).
5. Use the Pressure Check Kit shown in the Parts List
to check the relief pressure.
Refer to the Illustrations and Parts List for correct orien-
tation and placement of parts.
Apply hydraulic uid or O-ring lubricant to all O-rings
and all metal surfaces which they must slide over.
When installing an O-ring which must slide over sharp
surfaces, use a rolling motion and be careful not to
damage the O-ring.
Wherever the assembly results in metal-to-metal
contact, coat the surfaces with hydraulic uid or O-ring
lubricant.
Motor
1. Use an O-ring tool to install a new O-ring (4) from
the back end of the tool (1)
2. Lubricate drive shaft (8) and slide it into the tool
from the back end.
3. Install Woodruff key (9) onto the drive shaft. Align
the keyway in the gear (10) with the Woodruff key
on the drive shaft and install the gear onto the drive
shaft. Secure the gear with the retaining ring (11).
4. Install the drive pin (12) into the idler shaft (13). Align
the keyway in the remaining gear (10) with the drive
pin and install the gear onto the idler shaft. Install
the idler shaft with gear into the handle, meshing
the two gears together. Install the retaining ring (11).
5. Install dowel pins (14) into handle. Install new
gasket (15).
6. Install motor cap (6) onto handle. Secure motor cap
with cap screws (16). Torque cap screws to 10 to
11 Nm (95 to 100 in-lb). See the Torque Sequence
illustration.
Torque Sequence
1
3
4
2
5 7
8 6
20
Remove Spool
This Direction
Install Spool
This Direction
24
22
23
1921
26
60
25 30
Assembly

H8508 Impact Wrench
Greenlee / A Textron Company 84455 Boeing Dr. • Rockford, IL 61109-2988 USA • 815-397-7070
35
29 34
31
32
33
Assembly (cont’d)
Flow Control Cartridge
Install O-rings (64, 65) on ow control cartridge (63).
Install ow control cartridge in cavity of handle. Secure
with retaining ring (66).
Adjustable Torque Output Screw
Install O-ring (68) and backup ring (69) onto screw (67).
Install screw into cavity of handle. Twist the screw
clockwise until all threads are engaged in the handle.
Secure the screw with the roll pin (70).
Hammer Case Components
1. Apply Mobilgrease®HP to thrust bearing (43) and
work the grease into needle rollers. Apply a light lm
of grease to the thrust washers (44). Stack the thrust
washers and thrust bearing properly and place the
stack onto the drive shaft.
2. Place spacer (45) over the drive shaft with the ange
upward.
Impact Mechanism
1. Apply Mobilgrease®HP to the surfaces of the
hammer frame (46), hammers (47) hammer pin (48)
and anvil (49).
2. Install the two hammers, 180° from each other, into
hammer frame. Install pins into hammer frame and
through the hammers, then slide the assembly onto
the spline of drive shaft.
3. Pack hammer frame center space with Mobilgrease®
Special #53030-3. Install anvil into hammer frame
and through hammers.
4. Install O-ring (62) over threads on hammer case
cap (55).
5. Apply Loctite primer to threads of cap. Apply Loctite
primer to threads of handle at cap interface, ensuring
threads are free of grease and other contaminants
prior to application.
6. Slide the hammer case cap assembly (55, 56) over
the anvil and, using a wrench on the ats of the
cap, screw the assembly into the handle. Torque to
80-85 ft-lb.
Quick-Change Chuck (48755 Only)
1. Slide thrust ring lock (51) over anvil to the groove
closest to hammer case cap.
2. Insert two balls (54) into the holes in the anvil. Slide
the retaining sleeve (50) onto anvil with the anged
end upward. Insert spring (53) and thrust ring (52)
into retaining sleeve. Slide the thrust ring back and
install thrust ring lock (51) onto the anvil. Insert the
drive shank (61) into the chuck.
Trigger, Trigger Spool and Super Spool™
1. Install O-ring (34) on the Super Spool™ (31). Install
ball (32) in trigger spool cavity. Install Super Spool™
(31) into the trigger spool (29). Secure it with the
retaining ring (33).
2. Install O-ring (35) onto trigger spool assembly.
Install O-ring (27) and backup ring (28) in handle.
3. Slide trigger spool into handle from front end of the
tool. Slide washer (36) onto trigger spool and secure
with the retaining ring (37).
4. Slide spring (38) and washer (39) onto trigger
spool (29). Secure trigger (41) to trigger spool (29)
with spring pin (42).
5. Secure link (40) to handle and trigger with spring
pins (42).
Note: Support trigger (41) so pressing or tapping
on spring pins (42) does not bend trigger spool (29).
Trigger Spool™ (Shown in Open-Center Position)

Greenlee / A Textron Company 94455 Boeing Dr. • Rockford, IL 61109-2988 USA • 815-397-7070
H8508 Impact Wrench
Illustrations
48755 and 48760 Impact Wrench, Side View
40
42
39
41
1
37
35
29
5 4 153 14
10
6
9
12
11
11
7
13
27
28
33
34
31
32
45 44 4443
51
55
52 54
56 62
53 54
8
50 49
46 47 47 48
61
36
68
69
70
67
10
63
65
64
66

H8508 Impact Wrench
Greenlee / A Textron Company 10 4455 Boeing Dr. • Rockford, IL 61109-2988 USA • 815-397-7070
Illustrations (cont’d)
Reversing Spool
20
24*
22
23
1921
26
* Torque item (24) to 23 ft-lb.
60
25 30
35
29 34
31
32
33
Trigger Spool