Hitachi DH 40FR Technical Data And Service Manual page 22

(5) Reassembly of the tool holder
As illustrated in Fig. 18, ensure that the notched portions of the Stop Lever [7] and Knob (A) [3] are properly
aligned during reassembly. If not properly aligned and assembled, the tool (drill bit, bull point, etc.) cannot be
properly inserted into the retainer.
Needle Roller D4 x 20 [4]
Knob (A) [3]
Stopper Spring [2]
Stop Washer [1]
(6) Carbon brush inspection
The motor employs Carbon Brushes [84] which are
consumable parts. When they become worn to or
near "wear limit" (7 mm), it could result in motor
trouble. Replace the Carbon Brushes [84] with new
ones which are numbered "73" as shown in Fig. 19.
In addition, always keep Carbon Brushes [84] clean
and ensure that they slide freely within the brush
holders.
(7) Application of lubricant
Apply special grease (for hammer and rotary hammer) to the inner circumference of the Connecting Rod [25],
the O-rings [21] of the Striker [20] and the Piston [23], the sliding portion of the Second Hammer [10], O-ring
(C) [9] of the Second Hammer [10], the Damper [12], the inner and outer circumferences of the Bevel Gear
[26], Oil Seal (A) [43] and Oil Seal (B) [39]. Fill 50 g of the special grease in the Cylinder Crank Case [40] on
the Connecting Rod [25] side and 20 g in the Cylinder Crank Case [40] on the Clutch [22] side. Apply Hitachi
Motor Grease No. 29 to the Needle Bearing (M661) [56] and the pinion portion of the Armature Ass'y [75].
Fill 30 g of Hitachi Motor Grease No. 29 in the Cylinder Crank Case [40] on the First Gear [55] side and the
Gear Cover [57] side. Apply Doubrex 251 grease to the spline hole of the Second hammer [10].
(8) Oil seal and others
Take care not to scratch or cut Oil Seal (A) [43] and Oil Seal (B) [39] of the Cylinder Crank Case [40], the
O-ring (1AS-60) [8] of the Front Cover [5], O-ring (C) [9] of the Second Hammer [10], the Rubber Seal [32] of
the Crank Cover [30] and the O-ring [21] of the Piston [23] and the Striker [20].
Notch
Front Cover [5]
Fig. 18
--- 19 ---
Stop Lever [7]
Notch
Wear limit
No. of carbon brush
("73" means the last
two digits of the code
number.)
Fig. 19