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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 off 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).
Disassembly
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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 leather-
covered 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 fit 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 Arbor
For Models 77H120H63, 77H120H63-EU, 77H90H84,
77H90H84-EU, 77H120H84 and 77H120H84-EU,
grasp the
Arbor Housing (22) in a vise, guard up.
Use an applicable spanner wrench inserted into the pin hole of
the flange to hold the arbor. Using an open-end wrench, remove
the Wheel Nut (46 or 54).
Remove the Wheel Flanges (44 or 53) and Wheel Flange Pin (36A).
Unscrew and remove the Wheel Guard Screws (47 or 55). Remove
the Wheel Guard Lock Washers (48 or 56), Wheel Guard (43 or 52),
and Dust Seal (36B).
Lift the Arbor (35 or 36) and the Arbor Coupling (34) from the
Arbor Housing. Pull the Arbor Coupling off the Arbor.
Grasp the Arbor (35 or 36) in a vise, spline end up.
Using pliers, straighten the tangs of the Bearing Lock
Washer (41 or 50). Unscrew the Bearing Locknut (49 or 57) and
remove the Bearing Lock Washer.
If the Arbor Bearing (42 or 51) needs to be replaced, press it from
the Arbor Shaft.
For Models 77H90L10, 77H90L10-EU, 77H120L10 and 7H120L10-
EU,
grasp the Arbor Housing (22) in a vise, cone wheel up.
Using a No. 7RAQT-254 Cone Wheel Arbor Wrench to hold the
arbor, unscrew the cone wheel and remove it from the arbor.
Using a wrench on the flats, remove the Wheel Bearing Cap (60)
in the direction of the arrow on the face of the Cap. Lift the Wheel
Bearing Cap, Arbor Assembly (37) and Arbor Coupling (34) from
the Arbor Housing. Pull the Arbor Coupling off the Arbor.
Grasp the flats on the Arbor (37) in a vise, spline end up.
Using pliers, straighten the tangs of the Bearing Lock Washer (58).
Unscrew the Bearing Locknut (57) and remove the Bearing Lock
Washer.
Press the Arbor Bearing (59) from the Arbor Shaft.
Remove the Wheel Bearing Cap, Cap Spring (60A) and Dust
Washer (60B).
For Model 77H90G6,
grasp the Arbor Housing (22) in a vise,
collet end up.
Use a No. DG120-69 Collet Arbor Wrench to hold the Arbor. Using
a No. DG120-69 Collet Nut Wrench, remove the Collet Nut (65).
Remove the Collet (66) from the end of the arbor.
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Using a wrench on the flats, remove the Wheel Bearing Cap (64)
in the direction of the arrow on the face of the Cap. Remove the
Dust Washer (64B) and Cap Spring (64A).
Lift the Arbor (38) and the Arbor Coupling (34) from the Arbor
Housing. Pull the Arbor Coupling from the Arbor.
Grasp the Arbor (38) in a vise, spline end up.
Using pliers, straighten the tangs of the Bearing Lock Washer (62).
Unscrew the Bearing Locknut (61) and remove the Bearing Lock
Washer.
If the Arbor Bearing (63) needs to be replaced, press it from the
Arbor Shaft.
For Models 77H30B106, 77H30B106-EU, 77H50B106 and
77H50B106-EU,
grasp the Arbor Housing (22) in a vise, wire
brush up.
Use the 7RAQT-254 Wrench on the flats of the Wheel End Bearing
Nut to hold the arbor. Using the 7S60-24818 Wrench, remove the
Wire Brush Nut (78).
Remove the Wire Brush Lock Washer (76), Wire Brush Short
Spacer (77A), Wire Brush, Wire Brush Short Spacer (77A) and Wire
Brush Long Spacer (77).
Use a wrench on the flats at the end of the arbor to hold the arbor.
Using the 7RAQT4-254 Wrench, remove the Wheel End Bearing
Nut (75).
Using a wrench on the flats, remove the Wheel Bearing Cap (74)
in the direction of the arrow on the face of the Cap. Remove the
Dust Washer (74B) and Cap Spring (74A).
Remove the Wheel End Bearing (73).
Disassembly of the Throttle Lever and Inlet
Grasp the flats of the Throttle Handle (1) in a vise, 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 fit.
Drive out the Throttle Lever Pin (16) to release the Throttle Lever
Assembly.
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 lock ring pliers, pull the
Assembly from the Throttle Handle. Remove the two Seals (3).
Disassembly of the Motor and Throttle
Grasp the Arbor Housing (22) horizontally in a vise.
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 (28) and pull the motor from
the Throttle Handle.
Remove the Cylinder Dowel (32).
Grasp the splined end of the Rotor in leather-covered or copper-
covered vise jaws.
Remove the Front End Plate (30) and Front Rotor Bearing (31)
from the Rotor.
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Summary of Contents for 77H Series
Page 7: ...Notes...
