Milwaukee DD3-152 Bulletin (multi) (Service-DD3-152-en)

DD3-152

Repair instructions for the diamond core drill DD3-152

I. General

(a) The diamond core drill should only be repaired by authorized service centre. The following

explanations are in accordance with the spare parts list DD3-152 .

(b) To avoid electric shock, unplug the drill from the power supply before

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attempting service!

II. Dismantling the diamond core drill

1. Motor Section

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At first remove the additional handle (73). After that purge the gear oil from gearbox by
loosening cap screw 1/8” (44) and fill the gear oil in a proper container. Then loose the four
screws 5,5x50 (46) and remove motor with gear bearing shield from gearbox. Remove the
gearbox seal (32).

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To open the handle halves (12) remove the eight self-tapping screws 4,2x22 (29). As next
loosen two self-tapping screws 5,5x19 (21) and two self-tapping screws 4,8x38 (14) fixing the
right handle half on motor housing (3). Take off the upper handle half and deinstall switch (24),
capacitor (22), line cord (25), and cable grommet (26).

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Dismantle the left handle half from motor housing. Now exchange of circuit board (15) is
possible. Disconnect the circuit board (15) from stator (2) (2x coil winding, 2x PTC thermistor)
and release the two self-tapping screws 3,9x9,5 (16).

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Take out the carbon brushes (7). Subsequently, lift the gear bearing shield (31) and the rotor (1)
together out of motor housing using two mounting levers. Loose the two machine screws M4x16

(11) and press the rotor and the shaft seal (34) out of the gear bearing shield with pressing out

facility.

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Now the rotor (1) can be checked and exchanged if it is necessary. Take care of the bearings and
the correct position of the bearing cap (9). The removal of bearings from the rotor shaft requires
a pulling off facility.

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To exchange the motor housing (3) do the following. Disconnect the stator (2) from brushes.
Unscrew the brush holders (6) from motor housing and put them away. Take the air-guiding ring

(4) out of the motor housing and press out the stator.

2. Gearing Section

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Start dismantling gear by taking out the clutch (complete) (53). The torque of safety clutch must
be set at 16 Nm till 18 Nm. A special fixture is used to determine the torque setting. Don't built
in if not catching these values.

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Before deinstall the switching (77) unlock circlip (71) and remove loose wheel 2 (70). After
loosening of cheese-head screw M5x12

(20) take off the gear lever (18) and press out the switch

button (78). Check rubber round ring (80) for damaging.

DD3-152

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DD3-152

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Now pull out switch-actuating wheel (69) and pay attention to ball (58) and compression spring

(57). Remove the key (56) from spindle and unlock circlip (68) using special pliers to remove

loose wheel 1 (67).

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Next unlock snap ring (60) and press out spindle (54)
with ball bearing (59). Exchange of ball bearing (59) is
possible by unlocking snap ring (61) and press spindle
from ball bearing.

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Take care while exchanging shaft seals! Do not scratch
the bearing for seals in the gearbox housing. It would be
permeable for gear oil. At first unlock snap ring (62) an
press out the shaft seal (66) opposed drilling direction
using a bar of diameter 26mm.

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Then press out shaft seal (63) and pull out the two
scraper (64) (brass discs) and the spacer block (65). Last
pull out shaft seal (72) with special tool.

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Notice: If it is necessary to dismantle the prism block (40) gear oil can leak, when the gearbox
housing is filled with gear oil! Use Loctite screw glue on the screws M10x25 (43) for assembling
the prism block (40).

III. Assembling the diamond core drill

1. Motor Section

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Assembly starts with the motor housing (3). Press in the stator (2) without squeezing any wires.
After that screw the brush holders (6) on motor housing using spring washers (5) and screws
ZM4x12 (7). Screw brushes (7) and wires of stator on the brush holders (6).

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Now insert the air-guiding ring (4).

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In the next step press the greased shaft seal 15x21x3 (34) and the rotor (complete) (1) in the gear
bearing shield (31) and lock the rotor with two machine screws M4x16 (11), toothed washer,
washer and round ring. These will be set in with silicone glue for sealing. For better assembly the
bearing cap (9) can be sprayed slightly with Würth Carburettor Cleaner. Press the prepared
arrangement in motor housing exactly. The rotor should be movable easily. No wires must touch
the rotor! Then put in the brushes (7).

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Continue assembly with attaching the circuit board (15) to the motor housing. Check the back
side of circuit board of full covering with black protection layer. Connect the circuit board (16)
with wires of stator (2) (2x coil winding, 2x PTC thermistor) and the control wire.

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After that screw on the left handle half (12) on motor housing and mount switch (24) with
capacitor (22) and line cord (25) with calbe grommet (26). Do all electric connection –
switch/circuit board, switch/line cord, switch/control wire (see VI. Wiring Diagram). Lay the
wires for LED along the plastic pins and set the LED in LED-holder (41) in the gap of handle
half (12). Attention, all wires must be laying exactly without any squeezing!

DD3-152

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