Hitachi DH 40MC Service Manual

PRODUCT NAME

Hitachi Rotary Hammer

Model DH 40MC

CONFIDENTIAL

LIST No.
DH 40MC: F440
Dec. 2016

D

CONTENTS

REPAIR GUIDE -----------------------------------------------------------------------------------------------------------------1

1. Precautions on disassembly and reassembly ------------------------------------------------------------1

• Disassembly ----------------------------------------------------------------------------------------------------1

• Reassembly -----------------------------------------------------------------------------------------------------4

• Lubrication points and types of lubricant -----------------------------------------------------------------8

• Tightening torque ----------------------------------------------------------------------------------------------9

• Insulation test ---------------------------------------------------------------------------------------------------9

• No-load current value -----------------------------------------------------------------------------------------9

• Connecting diagram ---------------------------------------------------------------------------------------- 10

STANDARD REPAIR TIME (UNIT) SCHEDULES ------------------------------------------------------------------- 11

Page

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REPAIR GUIDE

1. Precautions on disassembly and reassembly

WARNING: Be sure to disconnect the power cord plug from the wall outlet before conducting

repair. Otherwise, the motor may run suddenly and you could get injured.

[Bold] numbers in the description below correspond to the item numbers in the parts list and exploded

assembly diagram for the Model DH 40MC.

1. Disassembly of the tool retainer

• Forcibly pull out the Front Cap [1] from the Retainer Sleeve [28] while pulling the Grip [11] in the arrow

direction as shown in Fig. 1.

• Remove the Stopper Ring [2] by using a retainer ring puller. Then the Grip [11], Retainer Washer [3],

Retainer Damper (A) [4], Bit Lock Holder [12], two Bit Locks [27], Thrust Plate [13], Retainer Spring [14]

and Spring Holder (A) [15] can be removed from the Retainer Sleeve [28] (Fig. 2).

Fig. 1

[1]

[11]

2. Disassembly of the hammering mechanism

(1) Removing the second hammer and striker

• Remove the Hex. Socket Hd. Bolt M6 x 25 [21] to remove the Cylinder Case [22], Spring Holder (B)

[37], Retainer Sleeve [28] and other parts from the main body.

• Remove the Second Hammer [30] from the Retainer Sleeve [28] together with the Damper Holder [33],

Damper [32] and Damper Washer [31].

• Pull out the Cylinder [36] from the main body together with the Lock Spring [38], Lock Sleeve [39],

Clutch Spring [40] and Clutch [41].

• Remove the Striker [34] by tapping the end surface of the Cylinder [36] with a plastic hammer.

Disassembly

Fig. 2

[28]

[2]

[11]

[12]

[3]

[4]

[27]

[13]

[15]

[14]

-1-

Fig. 3 • Removing the second hammer and striker

[28]

[32]

[31]

[33]

[37]

[30]

[22]

[24]

[25]

[26]

[39]

[40]

[41]

[85]

[34]

[36]

[38]

[47]

[48]

(2) Removing the piston ass’y

• Remove the Hex. Socket Hd. Bolt M5 [110] from the Crank Cover [111]. Detach the Crank Cover [111]

and the assembly of the Lever Shaft Holder [116] from the Crank Case Ass'y [91].

• Remove the Change Plate [119] from the Crank Case Ass'y [91].

• The piston ass’y can be removed from the main body without removing the Bevel Gear [43] and Slip

Clutch Ass’y [93]. Move the Connecting Rod [48] as shown below to remove the piston ass’y from the

Crank Shaft [85].

Fig. 4 • Removing the piston ass’y

[43]

[48]

[85]

Piston ass’y

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(3) Removing the first gear and crank shaft

• Remove the Hood [126] from the Crank Case Ass'y [91] by removing the Hex. Socket Hd. Bolt M5 x 12

[127] from the Hood [126].

• Remove the Seal Lock Hex. Socket Hd. Bolt M6 x 20 [109], Seal Lock Hex. Socket Hd. Bolt M6 x 45

[92], Hex. Socket Hd. Bolt M5 x 16 [75] and Tapping Screw D5 x 20 [65].

• Separate the Crank Case Ass'y [91] from the Housing Ass'y [55], Handle [76], and Gear Cover [108].

• Remove the Slip Clutch Ass'y [93] from the Crank Case Ass'y [91].

NOTE: Remove the Slip Clutch Ass'y [93] from the Crank Case Ass'y [91] beforehand because

the Bevel Gear [43] cannot be removed if the Slip Clutch Ass'y [93] remains in the Crank

Case Ass'y [91].

• Remove grease from the Piston [47] side and First Gear [123] side of the Crank Case Ass'y [91].

• Use a retaining ring puller to remove the Retaining Ring for D40 Hole [87] fixing the Ball Bearing

6203DD [88].

NOTE: At this time, turn the Crank Shaft [85] to expose the hole of the Retaining Ring for D40

Hole [87] prior to removal.

• Use a hand press to press the end face of the Crank Shaft [85], and then remove the First Gear [123]

and Crank Shaft [85] from the Crank Case Ass'y [91] as shown in Fig. 5.

Fig. 5 • Removing the first gear and crank shaft

[91]

[85]

Hand press

[91]

[123]

[88]

Release the Retaining
Ring for D40 Hole [101]
from the groove.

[85]

[87]

Adequate cradle

(4) Disassembly of the slip clutch ass’y

• Remove the Ball Bearing 629VV [106] by using

a bearing puller.

Fig. 6 • Disassembly of the slip clutch ass'y

[106]

Hand press

• Support Washer (A) [100] by an adequate

sleeve-like cradle as shown in Fig. 6.

• Use a hand press to press the Bevel Pinion [94]

on the Spacer [105] side.

[103]

[104]

[105]

[101]

• Detach the Gear Holder [102] and Spacer [105]

from the Bevel Pinion [94].

• When removing the Second Gear [101] from

the Gear Holder [102], put these parts in a

plastic bag and disassemble in the bag to avoid

[100]

[102]

losing Spring (C) [103] and Needle [104].

-3-

[94]

Cradle

Reassembly

Reassembly can be accomplished by reversing the disassembly procedure. However, special attention

should be given to the following items.

1. Reassembly of the hammering mechanism

(1) Mounting the first gear and crank shaft

• Press-fit Oil Seal (B) [90] to the Crank Case Ass'y

[91].

• Mount the O-ring (S-40) [89].

• Press-fit the Ball Bearing 6203DD [88].

• Use a retaining ring puller to mount the Retaining

Ring for D40 Hole [87].

• Press-fit the Crank Shaft [85] to the Ball Bearing

6203DD [88].

• Insert the Feather Key 3 x 3 x 8 [86] into the

Crank Shaft [85] groove.

• Support the plane of the Crank Shaft [85] with an

adequate steel rod and use an adequate tool to

press-fit the First Gear [123].

NOTE: Prior to press-fitting, make sure the

Feather Key 3 x 3 x 8 [86] matches the

key groove of the First Gear [123].

(2) Mounting the piston

• Insert the Connecting Rod [48] into the Piston [47], and then press-fit the Piston Pin [46] from the D8

hole (marked side) of the Piston [47].

NOTE: Be careful not to let the Piston Pin [46] project from the outer diameter of the Piston [47].

• Mount the O-ring [45] on the Piston [47] to make the piston ass’y.

• Next, turn the Crank Shaft [85] to the position shown below, and then mount the piston ass’y to the

Crank Shaft [85] from the Cylinder Case [22] side of the Crank Case Ass'y [91].

NOTE: The piston ass’y can be assembled even when the Bevel Gear [43] and Slip Clutch

Ass’y [93] are mounted to the Crank Case Ass'y [91].

Fig. 8 • Mounting the piston

[47]

[46]

“Φ2” concavity mark

[48]

Fig. 7 • Mounting the first gear and crank shaft

Adequate tool

[86]

[123]

[90]

[89]

[88]

[85]

[91]

Adequate steel rod

[85]

[87]

[45]

-4-

(3) Mounting the cylinder and retainer sleeve

• Mount the Retainer Damper Washer [26], Damper Sleeve [25], and Retainer Damper (B) [24] to the

Retainer Sleeve [28] in this order, while aligning the rounded surface of the Retainer Damper Washer

[26] with the rounded surface of the Retainer Sleeve [28].

• Insert the Second Hammer [30] (equipped with O-ring (C) [29]), Damper Washer [31], Damper [32],

and Damper Holder [33] into the Retainer Sleeve [28] in this order, while aligning the rounded surface

of the Damper Washer [31] with the rounded surface of the Second Hammer [30].

• Insert the assembly of the Retainer Sleeve [28] into the Cylinder Case [22].

NOTE: Be careful not to curl the lip of the oil seal.

• After inserting the Thrust Washer [44] and the Bevel Gear [43] into the Crank Case Ass'y [91], insert

the Slider [42] into the outer periphery of the Bevel Gear [43] along the Crank Case Ass'y [91] groove.

NOTE: The Bevel Gear [43] cannot be inserted if the Slip Clutch Ass'y [93] is mounted to the

Crank Case Ass'y [91] on ahead.

• Insert the Clutch [41] so that it engages with the internal claw of the Bevel Gear [43].

• Insert the Striker [34] equipped with the O-ring [35] into the Cylinder [36]. Fit the Clutch Spring [40] to

the Cylinder [36], and then insert the assembly of the Cylinder [36] into the Crank Case Ass'y [91].

• Insert the Lock Sleeve [39] into the Crank Case Ass'y [91], while aligning the inner spline groove of the

Crank Case Ass'y [91] with the Lock Sleeve [39] spline.

• Place the Lock Spring [38] and Spring Holder (B) [37] on the Lock Sleeve [39].

• Fit the protrusion of the Retainer Sleeve [28] in the Cylinder [36]

groove, and then mount the Cylinder

Case [22] equipped with the Retainer Sleeve [28] to the Crank Case Ass'y [91] equipped with the

Cylinder [36].

Fig. 9 • Mounting the cylinder and retainer sleeve

[28]

[22]

Be careful of the mounting direction.

[31]

[32]

[33]

[30]

[24]

[25] [26]

[37]

Be careful of the mounting direction.

[41]

[39]

[40]

[42]

[44]

[43]

[85]

[34]

[38]

[47]

[48]

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