Hitachi DH 18DPA Service Manual page 8

4. Reassembly of the hammering mechanism
NOTE: Degrease the M5 screw hole on Inner Cover (A) Ass'y [49]{49} using the parts cleaner before
reassembly of the hammering mechanism. Otherwise, the screw may be loosened and it may
cause troubles.
(1) Mount O-ring (A) [30]{30} to the Striker [29]{29} and push it in the Piston [31]{31} as shown in Fig. 9.
Mount the two Washers [42]{42} to the Piston [31]{31} and insert the Piston Pin [41]{41} into the Piston
[31]{31}.
(2) Mount O-ring (A) [36]{36} to Inner Cover (A) Ass'y [49]{49}. Put 6 grams of grease for rotary hammer in
the cylinder of Inner Cover (A) Ass'y [49]{49}.
(3) Insert the arm of the Reciprocating Bearing [45]{45} of the second shaft ass'y into the Piston [31]{31}
so that the arm of the Reciprocating Bearing [45]{45} is sandwiched between the two Washers [42]{42}
as shown in Fig. 9. Insert the rear end of Second Shaft (A) [43]{43} into Inner Cover (A) Ass'y [49]{49}.
(4) Allow the inner ring of the Reciprocating Bearing [45]{45} to make one rotation and check that the Piston
[31]{31} makes one reciprocation. Pull the Piston [31]{31} to check that it does not come off.
(5) Fit Inner Cover (B) [35]{35} in Inner Cover (A) Ass'y [49]{49} and tighten the two Seal Lock Hex. Socket
Hd. Bolts M5 x 14 [34]{34}.
Fig. 9 • Reassembly of the hammering mechanism
Put 6 grams of grease
for rotary hammer in it.
[42]{42}
[49]{49}
Arm of [45]{45}
[41]{41}
[36]{36}
[30]{30}
[35]{35}
-7-
[31]{31}
[29]{29}
[34]{34}