Ingersoll-Rand 77A25F107, 77A45W109, 77A60W107 Maintenance Information

16575128

Edition 2

May 2014

Save These Instructions

Air Grinder, Sander or Polisher

77A Series

Maintenance Information

2 16575128_ed2

Product Safety Information

WARNING

Failure to observe the following warnings, and to avoid these potentially hazardous situations, could result in death or serious
injury.
Read and understand this and all other supplied manuals before installing, operating, repairing, maintaining, changing accessories
on, or working near this product.
Always wear eye protection when operating or performing maintenance on this tool. The grade of protection required should be
assessed for each use and may include impact-resistant glasses with side shields, goggles, or a full face shield over those glasses.
Always turn o the air supply, bleed the air pressure and disconnect the air supply hose when not in use, before installing, removing
or adjusting any accessory on this tool, or before performing any maintenance on this tool or any accessory.
Do not use this tool if the actual free speed exceeds the rated rpm. Check the free speed of this tool before mounting any
accessories, after all tool repairs, before each job and after every 8 hours of use. Check speed with a calibrated tachometer, without
the abrasive product installed.

Note: When reading the instructions, refer to exploded diagrams in Parts Information Manuals when applicable (see under Related Documentation

for form numbers).

Lubrication

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Each time the Series 77A Grinder, Sander, and Polisher is
disassembled for maintenance, repair or replacement of parts,
lubricate the tool:

Moisten all O-rings with O-ring lubricant.
Coat the inner surface of the Arbor Coupling (42), the spline of the
Rotor (26) and the spline of the Bevel Pinion (31) with 3
to 4 cc of Ingersoll Rand No. 68 Grease. Do not substitute any

other grease.

1.

2.

After assembling the tool, remove the Oil Chamber Plug (7) and
ll the oil chamber with Ingersoll Rand No. 50 Oil. Tighten the
Plug to 3-3/4 to 7-1/2 ft-lb (5 to 10 Nm) torque. Inject 2.5 cc of
the recommended oil into the inlet before installing the Inlet
Bushing (4).
Inject 5 cc of Ingersoll Rand No. 68 Grease into both Grease
Fittings (44).

3.

4.

Disassembly
General Instructions

Do not disassemble the tool any further than necessary to replace
or repair damaged parts.
Whenever grasping a tool or part in a vise, always use leather­covered or copper-covered vise jaws to protect the surface of
the part and help prevent distortion. This is particularly true of
threaded members and housings.
Do not remove any part which is a press t in or on a subassembly
unless the removal of that part is necessary for repairs or
replacement.
Do not disassemble the tool unless you have a complete set of
new gaskets and O-rings for replacement.

Disassembly of the Angle Head

For Model 77A60P107, 77A60P109 or 77A75P107:

Grasp the Angle Arbor Housing (43) in leather-covered or copper­covered vise jaws, angle head up.
Insert a 5” (127 mm) long 3/16” hex wrench into the elongated slot
in the end of the Dead Handle (70) and loosen and remove the
screw and the Dead Handle from the Angle Arbor Housing (43).
Using the Autobalancer Wrench (Part No. 88V60-169) to hold the
Depressed Center Wheel Arbor (60) against rotation, proceed as
follows:

Using a hex wrench, unscrew and remove the Wheel Retaining
Screw (65).
For Type 27 and 28 Plain Hole Wheels, use the Depressed
Center Wheel Nut Spanner Wrench (Part No. D32-26) to
unscrew and remove the Depressed Center Wheel Nut (67).
Remove the wheel.

For Type 27 and 28 Mounted Wheels, unscrew the wheel.
For Type 27 and 28 Plain Hole Wheels, unscrew and remove

the Depressed Center Wheel Flange (66 or 68).
For Type 27 and 28 Mounted Wheels, remove any Depressed
Center Wheel Spacers (63).

4. Slide the Autobalancer Assembly (61) o the Arbor.

5. Unscrew and remove the Wheel Guard Screws (54). Remove the
Screw Lock Washers (53) and the Wheel Guard (59).

6. Lift the Depressed Center Wheel Arbor (60) from the Angle Arbor
Housing.

1.

2.

3.

4.

1.

2.

3.

a.

b.

c.

WARNING

Do not remove the Mounting Plate Pin (45) unless it is bent or
broken. The Mounting Plate Pin is the alignment pin for the
Wheel Guard and must be used to assure correct mounting of
the Wheel Guard. Use pliers to remove the Mounting Plate Pin if
removal is necessary and a new pin is available.

7. Remove the Angle Arbor Housing from the vise.

8. Lay the Angle Arbor Housing on a workbench, guard side down.
Lightly tap the angle arbor housing head with a soft hammer to
release the Upper Arbor Bearing (47) and Upper Bearing Spring
Washer (46).

NOTICE

A thread locking compound was applied to the threads of the
Bevel Gear Nut (48) during assembly. It may be necessary to
warm the Nut with a propane torch in order to remove it. Use
only enough heat to warm the Nut for removal. Do not overheat.

9. Grasp the ats of the Depressed Center Wheel Arbor in leather­covered or copper-covered vise jaws, Arbor Bearing end up. Using
a wrench, remove the Bevel Gear Nut.

10. Remove the Bevel Gear Spacer (49) and Bevel Gear (40).

11. Press the Arbor Lower Bearing Assembly (50) from the Arbor.
Remove the Lower Arbor Spring Washer (51). Remove the Arbor
from the vise.

For Model 77A25F107, 77A45W109 or 77A60W107:

Grasp the Angle Arbor Housing (43) in leather-covered or copper­covered vise jaws, angle head up.
Use a No. DG120-69 Sander Arbor Wrench to hold the Arbor (55).
Remove the Pad Mounting Kit nut (57).
For Model 77A25F107 Polisher, remove the Wool Bonnet (58).
Unscrew and remove the Sanding Pad Assembly (56).
For Model 77A45W109 or 77A60W107 Sander, remove the
Sanding Pad Assembly.
Remove the Pad Mounting Kit washers (57).
Unscrew and remove the Retaining Plate Screws (54). Remove the
Screw Lock Washers (53) and the Sander Arbor Retaining Plate (52).

1.

2.

3.

4.

5.

6.

16575128_ed2 3

WARNING

Do not remove the Mounting Plate Pin (45) unless it is bent or
broken. The Mounting Plate Pin is the alignment pin for the
Sander Arbor Retaining Plate. Use pliers to remove the Mounting
Plate Pin if removal is necessary and a new pin is on hand.

7. Remove the Angle Arbor Housing from the vise.

8. Lay the Angle Arbor Housing (43) on a workbench, guard side
down. Lightly tap the Angle Arbor Housing with a soft hammer to
release the Upper Arbor Bearing (47) and Upper Bearing Spring
Washer (46).

NOTICE

A thread locking compound was applied to the threads of the
Bevel Gear Nut (48) during assembly. It may be necessary to
warm the Nut with a propane torch in order to remove it. Use
only enough heat to warm the Nut for removal. Do not overheat.

9. Grasp the ats of the Sander Arbor (55) in leather-covered or
copper-covered vise jaws, arbor bearing end up. Using a wrench,
remove the Bevel Gear Nut.

10. Remove the Bevel Gear Spacer (49) and Bevel Gear (40).

11. Press the Arbor Lower Bearing Assembly (50) from the Arbor.
Remove the Lower Arbor Spring Washer (51). Remove the Arbor
from the vise.

Disassembly of the Throttle Lever and Inlet

Grasp the ats of the Throttle Handle (1) in leather-covered or
copper-covered vise jaws, air inlet up.
Remove the Inlet Bushing (4), Inlet Bushing Screen (5) and the
Throttle Valve Spring (6). The Bushing has an interference thread
and is tightly t.
Drive out the Throttle Lever Pin (16) to release the Throttle Lever
Assembly (17).
Remove the Throttle Handle from the vise.
Using a soft hammer, tap the arbor end of the housing to release
the Throttle Valve Assembly (2), or using snap ring pliers, pull the
Assembly from the Throttle Handle. Remove the two Seals (3).

Disassembly of the Motor and Throttle

Grasp the Angle Arbor Housing (43) horizontally in leather­covered or copper-covered vise jaws.
Using No. 77H-281 Coupling Nut Wrench, remove the Coupling
Nut (21).
Grasp the Throttle Handle (1) and pull the Handle from the Arbor
Housing.
Grasp the splined end of the Rotor (26) and pull the motor from
the Throttle Handle.
Remove the Cylinder Dowel (30).
Grasp the splined end of the Rotor in leather-covered or copper­covered vise jaws.
Remove the Front End Plate (28) and Front Rotor Bearing (29)
from the Rotor.
If the Front Rotor Bearing needs to be replaced, press it from the
Front End Plate.
Lift o the Cylinder (25).
Remove the Vanes (27).

NOTICE

A thread locking compound was applied to the threads of the
Rotor during assembly to prevent the Controller Assembly
(22) from loosening during operation. Before attempting to
unscrew the Assembly from the Rotor, apply moderate heat from
a propane torch to the middle of the rotor body to soften the
compound. Do not overheat the Rotor. Heat it only long enough
to allow the Controller Assembly to be unscrewed without using
excessive force.

1.

2.

3.

4.

5.

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2.

3.

4.

5.

6.

7.

8.

9.

10.

CAUTION

Use only the special Controller Wrench for removing the
Controller Assembly. Do not attempt to disassemble the
Controller. It is available only as a unit and is guaranteed for the
life of the Grinder if it is not abused.

11. Using No. 77H-950 Controller Wrench, unscrew and remove the
Controller Assembly (22).

NOTICE

The Rear End Plate, Spacer and Bearing are a matched set. Do not
mix the components with those of another set. The Rear Rotor
Bearing is always damaged during the removal process, and a
complete new Rear End Plate Assembly must be installed.

12. If the Rear End Plate Assembly (23) consisting of the Rear End
Plate, Spacer and Rear Rotor Bearing needs to be replaced, press
it from the Controller.

13. Remove the Rear End Plate Gasket (24).

14. Using No. 77H-154 Retainer Pliers, remove the Throttle Valve Seat
Support Retainer (15).

15. Grasp the Throttle Handle horizontally in leather-covered or
copper-covered vise jaws. Using a brass rod 8” (204 mm) long
inserted into the Air inlet end of the handle, lightly tap the brass
rod with a soft hammer to release the Throttle Valve Seat Support
Assembly (8).

16. Remove the Valve Seat Screw (9), Valve Seat Lock Washer (10),
Valve Seat Washer (11), Valve Seat (12) and Valve Support
Seals (13).

17. Check the Oiler Feeder Plug (14). Replace if necessary.

Disassembly of the Bevel Pinion Driver

For Model 77A25F107:

Lightly tap the Angle Arbor Housing (43) to release the Bevel
Pinion Driver (31).
Remove the Internal Gear (32).
Remove the Bevel Pinion Driver Bearing (33). This is a light press
t.
Check the Planet Gears (36) and Planet Gear Bearings (37) for
wear. If they need to be replaced, proceed as follows:

NOTICE

Always remove the Planet Gear Shafts (34) in the direction
shown on the drawing.

Using a pin punch and soft hammer, remove the Planet Gear
Shaft.
Remove the Planet Gear Assembly (36).
Remove the Planet Gear Bearing (37) from inside the Planet
Gear.
Remove the Rotor Pinion (35).

NOTICE

Always replace both Planet Gears even if only one Planet Gear
shows wear.

e. Remove the second Planet Gear as previously instructed.

5. Unscrew and remove the Pinion (40).

NOTICE

If the Pinion is worn or broken, replace both the Pinion and Bevel
Gear as they are a matched set and cannot be matched with
other Bevel Gears.

6. Press the Bevel Pinion Bearing (39) from the Bevel Pinion Driver.

7. Remove the Thrust Spacer (38).

1.

2.

3.

4.

a.

b.
c.

d.