Hitachi DH 52ME User manual

Overseas Sales Division
D
LIST No.
DH 52ME: F426
DH 52MEY: F427
May 2015
TROUBLESHOOTING GUIDE ---------------------------------------------------------------------------------------------1
1. Troubleshooting and corrective action ---------------------------------------------------------------------1
REPAIR GUIDE ----------------------------------------------------------------------------------------------------------------3
1. Precautions on disassembly and reassembly -----------------------------------------------------------3
STANDARD REPAIR TIME (UNIT) SCHEDULES ------------------------------------------------------------------ 19
CONTENTS Page
PRODUCT NAME
Hitachi Rotary Hammer
Models DH 52ME
DH 52MEY

-1-
[Bold] numbers in the description below correspond to the item numbers in the parts list and exploded
assembly diagram for the Model DH 52ME, {Bold} numbers to those for the Model DH 52MEY, and
<Bold> numbers to the item numbers for all models.
1. Troubleshooting and corrective action
Perform troubleshooting and take necessary corrective action as per the table below for any problem that
cannot be solved by taking corrective action described in the handling instructions.
Problem Cause Check Corrective action
All four LEDs of the
display lamp are
flashing.
• Broken Controller
Ass’y <63> • No check needed. • Replace the Controller Ass’y <63> with a new
one.
Three LEDs of the
display lamp are
flashing.
• Mix-up of three
internal wires of
the Stator Sensor
PCB Set <54>
and Controller
Ass’y <63>
• Check the heat-shrink tube
colors (red, black, and white)
of internal wires connecting
the Stator Sensor PCB Set
<54> and ControllerAss’y
<63>.
• Correctly connect
internal wires of the
Stator Sensor PCB Set
<54> and Controller
Ass’y <63> by their tube
colors (red, black, and
white).
• Broken Controller
Ass’y <63> • Check the state of the Controller Ass’y <63>
connector.
• Replace the Controller
Ass’y <63> with a new
one.
• Broken Rotor
<62> • Check the built-in magnet of
the fan for breaks. • Replace the Rotor <62> with a new one.
Two LEDs of the
display lamp are
flashing.
• Broken Controller
Ass’y <63> • No check needed. • Replace the Controller Ass’y <63> with a new
one.
One LED of the
display lamp is
flashing.
• Improperly
connected
connector cable of
the Stator Sensor
PCB Set <54>
• Check the plug-in state of the
connector cable.
(See “2. Reassembly of the
power supply unit” on page
13.)
• Firmly plug in the
connector cable.
• Broken Stator
Sensor PCB Set
<54>
• When the connector cable is
not defective • Replace the Stator Sensor PCB Set <54>
with a new one.
• Broken Controller
Ass’y <63> • Check the plug-in state of the Controller Ass’y <63>
connector.
• Replace the Controller
Ass’y <63> with a new
one.
• Broken Rotor
<62> • Check the built-in magnet of
the fan for breaks. • Replace the Rotor <62> with a new one.
TROUBLESHOOTING GUIDE

-2-
Problem Cause Check Corrective action
No LED of the
display lamp is ON.
• Improperly
connected
connector cable of
the Panel Ass’y
<67> PCB
• Check the plug-in state of the
connector cable.
(See “2. Reassembly of the
power supply unit” on page
13.)
• Firmly plug in the
connector cable.
• Internal wires
loosely plugged into
the Controller Ass’y
<63> and Filter
PCB Ass’y <71>
• Check the plug-in state of the
internal wires.
(See “2. Reassembly of the
power supply unit” on page
13.)
• Firmly plug in the
internal wires into the
Controller Ass’y <63>
and Filter PCB Ass’y
<71>.
• Broken Controller
Ass’y <63> • When the Controller Ass’y <63> connector is not
defective
• When the internal wire is not
defective
• Replace the Controller
Ass’y <63> with a new
one.
• Broken LED • When the connector cable is
not defective • Replace the Panel Ass’y <67> with a new
one.
• Broken Filter PCB
Ass’y <71> • When internal wires are not defective • Replace the Filter PCB Ass’y <71> with a new
one.
The motor does not
rotate even when
the trigger is pulled
with the speed
display LED ON.
• Internal wires
loosely connected
to the Switch <77>
• Check the plug-in state of
internal wires to the Switch
<77>. (See “2. Reassembly of
the power supply unit” on
page 13.)
• Firmly connect all
internal wires to the
Switch <77>.
• Broken Controller
Ass’y <63> • When internal wires of the Controller Ass’y <63> are not
defective
• Replace the Controller
Ass’y <63> with a new
one.
• Broken Switch <77> • When internal wires of the
Controller Ass’y <63> are not
defective
• Replace the Switch
<77> with a new one.
• Improperly inserted
connector cable of
On Lock PCB (A)
Ass’y <92>
• Check insertion of the
connector cable.
(See “2. Reassembly of the
power supply unit” on page
13.)
• Insert the connector
cable correctly.
The motor does not
rotate even when
the continuous
operation button is
pressed with the
speed indication
LED ON and the
hammering mode
selected.
• Improperly inserted
connector cable of
On Lock PCB (A)
Ass’y <92>
• Check the insertion of the
connector cable. (See “2.
Reassembly of the power
supply unit” on page 13.)
• Insert the connector
cable correctly.
• Broken On Lock
PCB (A) Ass’y <92> • When the connector cable of On Lock PCB (A)Ass’y <92>
is not defective
• Replace On Lock PCB
(A) Ass’y <92>.
• Broken Controller
Ass’y <63> • When the internal wire of the Controller Ass’y <63> is not
defective
• Replace the Controller
Ass’y <63>.
• Improperly inserted
connector cable of
On Lock PCB (B)
[109] {111}
• Check insertion of the
connector cable. (See “2.
Reassembly of the power
supply unit” on page 13.)
• Replace On Lock PCB
(B) [109] {111}.
• Broken On Lock
PCB (B) [109] {111} • When the connector cable of On Lock PCB (B) [109] {111}
is not defective
• Replace On Lock PCB
(B) [109] {111}.

-3-
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.
1. Disassembly of the tool retainer
Remove the Front Cap <1> while pulling the Grip <5> in the arrow direction. Note that the Front Cap <1> is
firmly fitted to the Retainer Sleeve <26>. Insert the edge of a flat-blade screwdriver or similar tool into the
gap between the Front Cap <1> and Grip <5>, and then pry up the Front Cap <1> by placing the fulcrum on
the Grip <5> as shown below. You can now separate the Grip <5> from the Retainer Sleeve <26>.
Use a retaining ring puller to remove the Stopper Ring <2>. You can now separate the Retainer Washer
<3>, Retainer Damper (A) <4>, Bit Lock Holder <6>, two Bit Locks <25>, Thrust Plate <7>, Retainer
Spring <8>, Spring Holder (A) <9> , and O-ring (S-26) <10> from the Retainer Sleeve <26>.
2. Disassembly of the hammering mechanism
(1) Removal of the second hammer and striker
(a) Remove the Bolt M5 x 18 [112] {121} and then detach the Crank Cover [111] {120} and lever shaft
holder ass'y from the Crank Case [125] {135}. Then take out the Change Plate [120] {129} and
Slider <43> from the Crank Case [125] {135}.
(b) Remove the Bolt M5 x 12 <12> from the Cylinder Case Cover <11> and then detach the Cylinder
Case Cover <11> from the Cylinder Case <18>.
(c) Remove the Bolt M8 x 35 <19>and detach the Cylinder Case <18> from the Crank Case [125]
{135}.
(d) Remove the Retaining Ring D40 <13> and pull out the Roll Pin D2 x 8 [101] {96} from the Cylinder
Case <18>. Then pull out the Retainer Sleeve <26>, Second Hammer <29>, Cylinder <33>, Striker
<34>, and other parts from the Cylinder Case <18> as a single assembly unit.
(e) Remove the Bevel Gear <46>, Metal (A) <44>, Metal Washer <45>, Slider <43>, Sleeve <42>,
Clutch <41>, Clutch Spring <40>, Lock Spring <38>, Lock Spring Washer <37>, Lock Sleeve <39>,
and Spring Holder (B) <36> from the assembly unit.
Disassembly
REPAIR GUIDE
Flat-blade screwdriver <26>
<5>
<1>
<4> <6> <8>
<3> <25>
<9> <10>
<2>

-4-
• Removal of the second hammer and striker
(f) Turn the Retainer Sleeve <26> and pull out the eight Needle Pins D8 <27> from the Retainer Sleeve
<26> to separate the Retainer Sleeve <26> from the Cylinder <33>.
(g) Remove the Second Hammer <29> together with the Damper Holder <32>, Damper <31>, and
Damper Washer <30> from the detached Retainer Sleeve <26>.
(h) Strike the end of the Cylinder <33> with a plastic hammer to pull out the Striker <34>.
(2) Removal of the piston ass’y
Remove the Retaining Ring for D12 Shaft [102] {101}, and then move the Connecting Rod <50> as
shown below. Remove the piston ass’y from the Crank Shaft [103] {102}.
[111] {120}
[120] {129}
Lever shaft holder ass'y
<46>
Cylinder case ass'y
<29>
<37>
<38>
<27>
Crank case ass'y
<42>
<44> <39>
<43>
<13>
[101] {96}
<30>
<32>
<40> <30>
<34>
Weight ass'y
Pin hole
<26>
<36>

-5-
• Removal of the piston ass’y
(3) Removal of the first gear and crank shaft
(a) Remove the Bolt M5 x 12 <68> and Screw D4 x 25 <79>, and then detach Handle (A) <70> and
Handle (B) <78>. Remove the Bolt M5 x 14 <59> and Bolt M5 x 16 <88>, and then detach the Back
Cover <87>.
(b) Remove the Bolt M6 x 45 [108] {130} and Bolt M6 x 22 [144] {154}, and then detach the Crank Case
[125] {135} from the Gear Cover [145] {155}.
NOTE: For the Model DH 52MEY, also remove the weight ass’y.
• Disassembly of the weight ass’y (Model DH 52MEY only)
Remove the Crank Cover {120} and then remove the Bolt M5 x 30 {113} from the Crank Case
{135}. Then take out the low-vibration mechanism.
(c) If the Slip Clutch Ass’y [126] {136} is difficult to remove from the Crank Case [125] {135} or Gear
Cover [145] {155}, strike it with a plastic hammer to remove it.
(d) Wipe off grease from the Piston <49> side and the First Gear [139] {149} side in the Crank Case
[125] {135}, and then use a retaining ring puller to remove the Retaining Ring for D47 Hole [105]
{104} that retains the Ball Bearing 6204DD [106] {105}, while turning the Crank Shaft [103] {102} so
that you can see the hole of the Retaining Ring for D47 Hole [105] {104}.
(e) Place the Crank Case [125] {135} on an adequate cradle with its Piston <49> facing down, and then
use a hand press to press down on the end surface of the Crank Shaft [103] {102}. The Second
Pinion [140] {150}, First Gear [139] {1491}, and Crank Shaft [103] {102} can now be removed from
the Crank Case [125] {135}.
Adequate cradle
Hand press
[103] {102}
[105] {104}
[125] {135}
[125] {135}
[103] {102}
[105] {104}
[141]{151}
[142]{152} [106] {105}
<50> [102] {101} [103] {102}
Piston ass'y
Crank case ass'y

-6-
(4) Removal of the slip clutch ass’y
(a) Use a bearing puller to remove the Ball
Bearing 629VV [138] {148}.
(b) Use an adequate sleeve-like cradle to
support Washer (A) [132] {142} as shown
below. Use a hand press to press the Bevel
Pinion [127] {137} on the Spacer [137] {147}
side. Detach the Gear Holder [133] {143}
and Spacer [137] {147} from the Bevel
Pinion [127] {137}.
(c) When removing the Second Gear [136] {146}
from the Gear Holder [133] {143}, put these
parts in a plastic bag and disassemble in the
bag to avoid losing Spring (C) [135] {145}
and the Needle Pin D6 x 6 [134] {144}.
3. Disassembly of the motor
(1) Firmly hold the Housing <55> and use a plastic
hammer to tap the shaft of the Rotor <62> until
the spigot joint of the Gear Cover [145] {155} is
removed from the Housing <55>.
(2) The Rotor <62> has strong magnetic force.
Firmly hold the Housing <55> and pull out the
Gear Cover [145] {155} from the Housing <55>.
NOTE: When the Gear Cover [145] {155} is
separated from the Rotor <62> and
the Rotor <62> remains in the
Housing <55>, press the Housing
<55> and push the shaft section of
the Rotor <62> to remove the motor.
Tap the shaft of the Rotor <62>.
• Removal of the slip clutch
[138]{148}
Adequate cradle
[132]{142}
[136]{146}
[127]{137}
[137]{147}
[133]{143}
[135]{145}
Hand press
[134]{144}
• Disassembly of motor
[145] {155}
<55>
<62>

-7-
Reassembly can be conducted by reversing the disassembly procedure. However, special attention should
be given to the following items.
1. Reassembly of the hammering mechanism and low vibration mechanism
(1) Mounting the first gear and crank shaft
(a) Press-fit Oil Seal [124] {134} to the Crank
Case [125] {135}. Mount the O-ring (F)
[107] {106}. Press-fit the Ball Bearing
6204DD [106] {105}. Use a retaining ring
puller to mount the Retaining Ring for D47
Hole [105] {104}. Press-fit the Crank Shaft
[103] {102} to the Ball Bearing 6204DD
[106] {105}.
(b) Insert the Feather Key [104] {103} into the
Crank Shaft [103] {102} groove. Support
the plane of the Crank Shaft [103] {102}
with an adequate steel rod and use an
adequate tool to press-fit the First Gear
[139] {149}. Simillarly press-fit the Second
Pinion [140] {150}.
NOTE: Prior to press-fitting, make sure
the Feather Key [104] {103}
matches the key groove of the
First Gear [139] {149} and the
Second Pinion [140] {150}.
(2) Mounting the piston
(a) Insert the Connecting Rod <50> into the Piston <49> and then press-fit the Piston Pin <48> into the
D10 hole (marked “ĭ2”) of the Piston <49>. Then mount the O-ring <47> on the Piston <49> to
complete the piston ass’y.
NOTE: Be careful not to let the Piston Pin <48> project from the outer diameter of the Piston
<49>.
(b) Next, turn the Crank Shaft [103] {102} to the position shown below, and then mount the piston
ass’y to the Crank Shaft [103] {102} from the Cylinder Case <18> side of the Crank Case [125]
{135}. Use a retaining ring puller to fix the Retaining Ring for D12 Shaft [102] {101}.
Reassembly
Adequate tool
[125] {135}
Adequate steel rod
[103] {102}
[104] {103}
[139]{149}
[107] {106}
[124]{134}
[106] {105}
[102] {101}
[103] {102}
<50>
<49>
<47>
<48> Marked with “ĭ2”

-8-
(3) Mounting the cylinder and retainer sleeve
(a) Insert the Second Hammer <29> with O-ring <28>, Damper Washer <30>, Damper <31>, and
Damper Holder <32> to the Retainer Sleeve <26> in this order.
NOTE: Match the rounded surface of the Damper Washer <30> with the rounded surface of
the Second Hammer <29>.
(b) Insert the Cylinder <33> into the Retainer Sleeve <26> and insert eight Needle Pins D8 <27> into
the 8 mm dia. hole to connect them. To avoid dropping, apply Hitachi Motor Grease No. 29 to the
inside of Spring Holder (B) <36> lightly and then cover the needle pin insertion section of the
Retainer Sleeve <26> with Spring Holder (B) <36>.
(c) Insert the Striker <34> with O-ring <35> into the Cylinder <33> in the direction indicated in the figure.
(d) Mount the Retainer Damper Washer <24>, Damper Sleeve <23>, Retainer Damper (B) <22>, and
the Retainer Damper Holder <21> around the tip of the Retainer Sleeve <26> in this order.
NOTE: Match the rounded surface of the Retainer Damper Washer <24> with the rounded
surface of the Retainer Sleeve <26>. The Damper Sleeve <23> must be at the Retainer
Damper Washer <24> side.
(e) Insert the Retainer Sleeve <26> into Ball Bearing 6008DD <15> in the Cylinder Case <18> ass’y,
and then fix it with Retaining Ring D40 <13>.
NOTE: Insert the Retainer Sleeve <26> straight in to avoid turning up the lip section of the Oil
Seal <17>.
(f) Insert the Lock Spring Washer <37> deep into the Cylinder Case <18>. Insert the Lock Spring <38>
until it contacts the Lock Spring Washer <37>. Then insert the Lock Sleeve <39> until it contacts the
Lock Spring <38>.
(g) Insert the Clutch Spring <40> until it contacts Spring Holder (B) <36> and then insert the Clutch
<41>.
(h) Insert the Sleeve <42>, Slider <43>, Metal (A) <44>, Metal Washer <45>, and Bevel Gear <46> into
the Cylinder Case <18> in the direction indicated in the figure. Fix Metal (A) <44> and the Cylinder
Case <18> with the Roll Pin D2 x 8 [101] {107}.
NOTE: Be sure to insert the parts in the direction indicated in the figure. If Metal (A) <44>
cannot be deeply inserted into the Cylinder Case <18>, secure the top of the Retainer
Sleeve <26> and then engage the Clutch <41> with the Bevel Gear <46>. Then rotate
the Bevel Gear <46> and engage the spline grooves of the Clutch <41> with those of
the Cylinder <33>. Nevertheless, if Metal (A) cannot be deeply inserted into the
Cylinder Case <18>, secure the Cylinder Case <18> and rotate the Bevel Gear <46>
again, and then engage the spline groove of the Lock Sleeve <39> with the spline
groove of the Cylinder Case <18>. If these parts do not engage well, repeat the
procedure from step (h) above.

-9-
• Mounting the cylinder and retainer sleeve
<37> Position the concave portions
sideways.
Avoid the Oil Seal <17>
from being turned up.
Pay attention to the direction of the Retainer Damper
Washer <24> and Damper Washer <31>.
<39>
Insert position of the Lock Spring Washer <37>
Position the notch downward.
Position the slider groove upward.
Insert from the convex side.
<45>
Engage the clutch with the bevel gear.
Engage the Lock Sleeve <39> with the Clutch <41>.
Engage the Clutch <41>
with the Cylinder <33>.
Engage the Lock Sleeve <39>
with the Cylinder Case <18>.
<38>
[101] {107}
<18>
<40> <41> <42> <44> <46>
<34> <35> <33>

-10-
(4) Reassembly of the slip clutch ass’y
(a) Press-fit the Collar [129] {139} and Ball Bearing 6002DD [130] {140} in this order to the Bevel Pinion
[127] {137}, and then insert the Washer [131] {141} and Washer (A) [132] {142} in this order.
(b) Mount the Feather Key [128] {138} to the Bevel Pinion [127] {137} and then press-fit the Gear
Holder [133] {143}.
(c) Insert the Second Gear [136] {146} into the outer periphery of the Gear Holder [133] {143}.
NOTE: Apply Hitachi Motor Grease No. 29 to the inner periphery of the Second Gear [136]
{146} in advance.
(d) Insert the eight Needle Pins D6 x 6 [134] {144} upright as shown below, and then push in eight
Springs (C) [135] {145}.
(e) Fill up the slotted groove and through-hole portions of the Gear Holder [133] {143} with Hitachi Motor
Grease No. 29, and then press-fit the Spacer [137] {147} and Ball Bearing 629VV [138] {148} in this
order to the Bevel Pinion [127] {137}.
(5) Reassembly of the vibration reduction mechanism
(a) Apply Hitachi Motor Grease No. 29 to the Washer {109} and adhere it to the end face of the hole
portion of the Weight {110}.
(b) Insert the Weight {110} into the Base {116}, and then insert the Weight Pin {112}.
NOTE: At this time, apply Hitachi Motor Grease No. 29 to the Weight Pin {112}.
(c) Sandwich the Base {116} between Leaf Spring (A)
{114} and the Spring Holder {115} engaging the
convex portion of the Base {116} with the concave
portion of the Spring Holder {115}, and then secure
it with the Bolt M5 x 16 {118}.
NOTE: At this time, apply Hitachi Motor Grease
No. 29 to the tip of Leaf Spring (A) {114}
where the Weight {110} will contact.
(d) Insert the two Weight Bumpers {117} into the back
of the Base {116} so that the rounded portion of the
Weight Bumper {117} contacts the Weight {110}.
(e) Fit two Cylinder O-rings (B) {108} around the
Weight {110} without twisting.
[127]{137}
[132]{142}
[136]{146} [138]{148} [137]{147}
[130]{140}
[129]{139} [127]{137}
[133]{143} [134]{144}
[135]{145}
[128]{138}
A
A
Slotted groove in
the gear holder
Section A—A
[131]{141}
{108}
{114}
{114}
{109}
{112}
{118}
{115}
{117}
{110}
{116}
{115}
{118}

-11-
• Reassembly of the lever shaft holder ass’y
• Mounting the valve and felt
[113] {122}
[114] {123}
mark
[109] {111}
[115] {124}
[116] {125}
[117] {126}
(6) Reassembly of the lever shaft holder ass’y
(a) Apply Hitachi Motor Grease No. 29 to the O-ring (S-18) [116] {125}, and then attach the O-ring to the
Change Lever [113] {122}. Insert the Lever Spring [114] {123} into the change lever hole.
(b) Fit On Lock PCB (B) [109] {111} in the depressed portion of the Lever Shaft Holder [117] {126}.
Apply Hitachi Motor Grease No. 29 to the Steel Balls D4.76 [115] {124} and place them into the
concave portion.
(c) Position the Lever Spring [114] {123} and Steel Balls D4.76 [115] {124} properly. Insert the Change
Lever [113] {122} into the hole of the Lever Shaft Holder [117] {126} and fix it with the Retaining
Ring for D20 Shaft [118] {127}.
NOTE: Rotate the Change Lever [113] {122} to check that the lever clicks at each mode
position. Insert the Change Lever [113] {122} into the Lever Shaft Holder [117] {126}
straight to avoid damaging the O-ring.
(7) Mounting the valve and felt
(a) Insert the Valve [123] {133} into the cylindrical hole at the side of the crank case. Tighten the Cap
Screw [122] {132} at the tightening torque of 80±10 kgf•cm. Attach Felt Packing (C) [121] {131} as
shown in the figure below.
(b) Attach Felt Packing (D) [110] {119} to the crank cover as shown in the figure below.
Eccentric pin
[121] {131}
[122] {132}
[123] {133}
[125] {135}
[110] {119}
Co
nt
ac
t with th
e
c
r
a
nk
co
v
e
r.
Ventilation window
Contact with the
ventilation window. [111] {120}

-12-
• Mounting the change plate
(8) Mounting the crank cover
(a) Insert the stepped portion of the Change Plate [120] {129} into the notch of the Slider <43>.
NOTE: Be sure to insert the stepped portion in the right direction according to the figure
below.
(b) Attach O-ring (A) [119] {128} to the lower outer circumference of the Lever Shaft Holder [117] {126}
and set the Change Lever [113] {122} to the position of “Rotation + hammering” mode.
(c) Place the lever shaft holder ass’y and Crank Cover [111] {120} on the Crank Case [125] {135}, and
fix both parts with the Bolt M5 x 18 [112] {121}.
NOTE: After fixing the parts in place, check that the Change Lever [113] {122} rotates
smoothly, that the Retainer Sleeve <26> does not rotate when changing to
“Hammering only” mode, and that the Retainer Sleeve <26> rotates smoothly when
setting to “Neutral” mode. Do not get the wiring of On Lock PCB (B) [109] {111} caught
in when setting the Crank Cover [111] {120} in place.
2. Reassembly of the power supply unit
(1) Mounting the rotor ass’y
Before inserting the Rotor <62> into the Housing <55>, mount the Rotor <62> on the Gear Cover [145]
{155}.
NOTE: Without the gear cover, the Rotor <62> will be strongly attracted and fixed to the Stator
Sensor PCB Set <54> by its own magnetic force. Be careful not to let your hand be
suddenly pulled by the magnetic force of the Rotor <62>.
Insert the Gear Cover [145] {155} into the Housing <56> in proper direction. Press-fit the Gear Cover
[145] {155} into the Housing <55> as far as it will go by using an appropriate jig, so that the spigot joint
section of the Gear Cover [145] {155} can be pushed evenly.
(2) Wiring of the controller set
(a) Pass the red, white, and black terminals of the Stator Sensor PCB Set <54> through the center
window of the ControllerAss’y <63>, and then connect the terminals with those of the same color on
the Controller Ass’y <63>.
NOTE: Insert the terminals all the way in.
(b) Pass the five connectors of the Stator Sensor PCB Set <54> through the center window of the
Controller Ass’y <63>, and then insert the connectors into those of the Controller Ass’y <63>.
NOTE: Do not insert the connectors in the wrong direction.
(c) Insert the eight connectors of the Panel Ass’y <67> into the connectors of the Controller Ass’y <63>.
NOTE: Do not insert the connectors in the wrong direction.
Stepped portion of the Change Plate [120] {129}
Notch of the Slider <43>

-13-
(d) Pass the three connectors of the Controller Ass’y <63> through the lower window of the Back Cover
<87>, and then insert the connectors into those of On Lock PCB (A) Ass’y <92>.
NOTE: Do not insert the connectors in the wrong direction.
(e) Insert the three connectors of On Lock PCB (B) [109] {111} into the connectors of the Controller
Ass’y <63>.
NOTE: Do not insert the connectors in the wrong direction.
(3) Wiring of the filter PCB set (See the figure on page 15.)
(a) Pass the two terminal-attached internal wires of the Controller Ass’y <63> through the lower window
of the Back Cover <87>, and then connect the internal wires with the two terminal-attached internal
wires of the Filter PCBAss’y <71>.
NOTE: Connect the crimp-type terminals with those of the same colors. Insert the terminals
all the way in.
(b) Connect the two core-exposed internal wires of the Filter PCB Ass’y <71> with Pillar Terminal (A)
<81>.
(4) Wiring of the switch (See the figure on page 15.)
Pass one core-exposed internal wire of the Controller Ass’y <63> through the window of the Back Cover
<87>, and then connect it with the terminal No. 2 or 3 of the Switch <77>.
Connect one core-exposed internal wire of On Lock PCB (A) Ass’y <92> with the terminal No. 2 or 3 of
the Switch <77> (whichever is not connected).
NOTE: The internal wires are connectable with either terminal.
(5) Wiring of the cord (See the figure on page 15.)
Connect the core-exposed internal wires of the Cord <85> to Pillar Terminal (A) <81>.
NOTE: The internal wires are connectable with either terminal.
(6) Mounting the back cover
(a) Attach the Dust Seal <56> and Packing (B) <57> to the Tail Cover <58> and mount it to the Housing
<55>. Then fix it with the Bolts M5 x 14 <59>.
(b) Insert the two shafts on top of the Housing <55> into the two holes of the Controller Ass’y <63>.
Pass the internal wire of On Lock PCB (B) [109] {111} through the notch at the rear of the Panel
Ass’y <67>, and then insert the two shafts on top of the Housing <55> into the two holes of the Panel
Ass’y <67>.
(c) Mount the Back Cover <87> without getting the internal wires caught and fix it to the Housing <55>
with four Bolts M5 x 16 <88>. Then fix it to the Crank Case [125] {135} with two Bolts M5 x 14 <59>.

-14-
• Mounting handles (A) and (B)
(7) Mounting handles (A) and (B)
(a) Insert the Handle Shaft <86> into Handle (A) <70> and fix it with the Screw D4 x 25 <79>.
(b) Insert the Cord <85> and Cord Armor <82> and then fix the Cord Clip <83> with the Screw D4 x 16
<84>. Bring the flat side of the Cord Clip <83> in contact with the Cord <85> when mounting.
(c) Insert the hinge shaft of Handle (A) <70> into the hinge hole of the Back Cover <87> and fix Handle
(A) <70> to the Transatory Unit <72> with Distance Piece (B) <69> and the Bolt M5 x 12 <68>.
(d) Fit the Filter PCB Ass’y <71>, On Lock PCB (A) Ass’y <92>, On Lock Spring <91>, On Lock Button
<90>, Pillar Terminal (A) <81>, the connectors to connect On Lock PCB (A) Ass’y <92> and
Controller Ass’y <63>, Switch <77>, and Trigger <76> into the positions shown in the figure.
NOTE: Do not insert the Filter PCB Ass’y <71>, On Lock PCB (A) Ass’y <92>, and On Lock
Button <90> in the wrong direction.
(e) Put the internal wires in Handle (A) <70> and mount Handle (B) <79> without getting the internal
wires caught.
The blue-colored capacitor of the Filter PCB
Ass’y <71> must be on the back cover side.
<76>
<77>
<81>
<90> <91>
<72>
<92>
Connector to connect On
Lock PCB (A) Ass’y <92>
and Controller Ass’y <63>
<70>
Connector to connect the
Filter PCB Ass’y <71> and
Controller Ass’y <63>
Install Handle (B) <79> with the internal wires
and connectors pushed in not to protrude from
the rib of Handle (A) <70>.

-15-
• Reassembly of power supply unit
<77>
<67>
<54>
Check the
connector
orientation.
Check the
connector
orientation.
<63>
<71>
<82>
Interchangeable
wires
<81>
Interchangeable
wires
<85>
Check the
connector
orientation.
Check the
connector
orientation.
<92>
[109] {111}
Interchangeable
wires
Red
Red
Black
Black
Red
Black
White

-16-
• Specified grease (for hammer, hammer drill)
Fill or apply specified grease (for hammer, hammer drill) to the following points.
• Fill 65 g of specified grease in the Crank Case [125] {135} on the Connecting Rod <50> side.
• Apply specified grease to the inner and outer diameter portions of the Cylinder <33>, sliding portion of the
Striker <34>, and O-ring <35> of the Striker <34>.
• Apply specified grease to the inner diameter portion of the Connecting Rod <50>, outer diameter portion
of the Piston <49>, and O-ring <47> of the Piston <49>.
• Apply specified grease to the sliding portion of the Second Hammer <29> and O-ring <28> of the Second
Hammer <29>.
• Apply specified grease to the inner lips of Oil Seal [124] {134}, inner and outer diameter portions of the
Bevel Gear <46>, Metal Washer <45>, inner periphery of the Clutch <41>, inner lip of the Oil Seal <17> in
the Cylinder Case <18>, Damper <31>, Retainer Damper (B) <22>, and the inner and outer peripheral
polished surfaces of the Retainer Sleeve <26>.
Fill or apply Hitachi Motor Grease No. 29 to the following points.
• Fill a total of 30 g of grease in the Crank Case [125] {135} on the First Gear [139] {149} side and the Gear
Cover [145] {155} side.
• Apply a total of 5 g of grease to the 8 mm dia. holes of the Gear Holder [133] {143} and Spring (C) [135]
{145}.
• Apply grease to the Weight Pin {112}, weight pin inserting portion of the Base {116}, Washer {110}, sliding
surfaces of Leaf Spring (B) {114} and Weight Ass’y {109} and inner periphery of the 6 mm diameter hole
as shown in the figure on page 17.
• Apply grease to the pinion portion of the Rotor <62>, Bit Lock <25>, Bearing Washer (C) [142] {152},
Needle Pin D6 x 6 [134] {144} and inner periphery of the Second Gear [136] {146}.
• Apply grease to Steel Ball D4.76 [115] {124} and O-ring (S-18) [116] {125} in the lever shaft holder ass’y.
CAUTION: Both viscosity and consistency of the specified grease are optimized for the rotary
hammer Models DH 52ME and DH 52MEY in order to prolong the service life.
Therefore, applying ordinary grease intended for other models (e.g. Model
DH 40MEY) to the Models DH 52ME and DH 52MEY may dramatically shorten the
product’s service life.
Net weight Code No.
500 g 980927
30 g 981840
Lubrication points and types of lubricant
30 g
500 g

-17-
• Application of Hitachi Motor Grease No. 29 to the weight pin and leaf spring (B)
CAUTION: Be sure to apply TB1401 screw locking agent to the threads of the following screws and
bolts. Otherwise, the screws or bolts loosened by vibration could cause damage to the
product body.
M8
• Bolt M8 x 35 <19> for mounting the cylinder case ······························ 19.6 N•m (200 kgf•cm)
M6
• Bolt M6 x 45 [108] {130} for mounting the crank case (housing side)······ 9.8 N•m (100 kgf•cm)
• Bolt M6 x 22 [144] {154} for mounting the gear cover (crank case side)·· 9.8 N•m (100 kgf•cm)
M5
• Bolt M5 x 18 [112] {121} for mounting the crank cover ························ 7.84 N•m (80 kgf•cm)
• Bolt M5 x 12 <68> for mounting the handles (A) and (B)······················ 4.9 N•m (50 kgf•cm)
• Bolt M5 x 14 <59> and Bolt M5 x 16 <88> for mounting the back cover··· 3.92±0.49 N•m (40±5 kgf•cm)
• Bolt M5 x 14 <59> for mounting the tail cover···································· 5.9±1.5 N•m (60±15 kgf•cm)
• Bolt M5 x 12 <12> for mounting the cylinder case cover ······················ 3.92±0.49 N•m (40±5 kgf•cm)
• Bolt M5 x 30 {113} for mounting the vibration absorber························ 7.84 N•m (80 kgf•cm)
• Bolt M5 x 16 {118} for mounting the spring holder ······························ 7.84 N•m (80 kgf•cm)
D4
• Screw D4 x 16 <84> for mounting the cord clip·································· 1.96±0.49 N•m (20±5 kgf•cm)
• Screw D4 x 25 <79> for mounting the handles (A) and (B)··················· 1.96±0.49 N•m (20±5 kgf•cm)
D5
• Screw D5 x 60 <53> for mounting the stator sensor PCB set················ 2.94±0.49 N•m (30±5 kgf•cm)
Tightening torque
+1.96
0+20
0
+1.96
0+20
0
+0.98
0+10
0
+0.98
0+10
0
+1.96
0+20
0
+1.96
0+20
0
+1.96
0+20
0
Weight Pin {112} Leaf Spring (B) {114}
Weight Ass’y {109}
Washer {110}
Apply grease to the sliding
portions with the weight.
Apply grease to the sliding
surface of the outside.
Apply grease to both sides and
attach it to the weight.

-18-
• Wiring diagram
After completing disassembly and repair, measure the insulation resistance and dielectric strength.
Insulation resistance: 7 Mȍor higher (as measured with a 500 VDC megohm tester)
Dielectric strength: 4,000 VAC/1 minute, with no abnormalities --- 220 to 240 V and 110 V for UK products
2,500 VAC/1 minute, with no abnormalities --- 110 to 127 V (Except UK products)
After no-load operation for 30 minutes, the no-load current values should be as follows:
Voltage 110 V 120 V 127 V 220 V 230 V 240 V
Current max. 5.7 A 5.4 A 5.0 A 3.2 A 3.0 A 2.9 A
Connecting diagram
No-load current value
Insulation test
5-wire
8-wire
Panel Ass’y
<67> On Lock PCB
(A) Ass’y <92>
Controller Ass’y
<63>
Stator Sensor
PCB Set <54> Filter PCB
Ass’y <71>
On Lock PCB
(B) [109] {111}
Switch <77>
3-wire
3-wire
Pilla
r
terminal
Red
BlackBlack
Red
Red
White
Black Black
Red
White

-19-
MODEL Variable
Fixed 10 20 30 40 50 60
DH 52ME
General assembly
Back Cover
Transatory
Unit
Cylinder
Case
Retainer
Sleeve
Retainer
Damper (B)
Retainer
Damper
Holder
Second
Hammer
Damper
Damper
Holder
Ball Bearing
6008DD
Controller
Ass’y
Panel Ass’y
Cylinder
Striker
O-ring
Clutch
Lock Sleeve
Spring
Holder (B)
Slider
Piston
O-ring
Connecting
Rod
Gear Cover
Rotor Ass’y
Ball Bearing
6202DD
Ball Bearing
6201VV
Crank Shaft
Ball Bearing
6204DD
First Gear
Second
Pinion
Slip Clutch
Ass’y
Bevel Gear
Housing
Stator
Sensor
PCB Set
Crank Case
Work Flow
Handle (A)
Handle (B)
Switch
Filter
PCB Ass’y
Cord
Cord Armor
Tail Cover
Crank Cover
Change
Lever
Lever Shaft
Holder
On Lock
PCB (B)
Change
Plate
On Lock
Button
On Lock
PCB (A)
Ass’y
Front Cap
Grip
Cylinder
Case Cover
Retainer
Washer
Retainer
Damper (A)
Bit Lock
Holder
Bit Lock
Thrust Plate
Spring
Holder (A)
STANDARD REPAIR TIME (UNIT) SCHEDULES