Hitachi NR 1890DC Service Manual page 15

• Remove the valve core from the Chamber Base [10](10) by using a commercial valve core tool. (See Fig.
11.)
Fig. 11
Bit type
• Remove the four Nylock Bolts M6 [11](11) that fasten the Chamber Base [10](10) and Chamber Cover
[4](4), and remove the Chamber Base [10](10).
NOTE: If it is difficult to remove the Chamber Base [10](10), temporarily tighten at least two Nylock
Bolts M6 [11](11) so that the threaded portion is shown 3.5 mm to 6.5 mm as shown in Fig.
12. Mount the reduction valve set and feed compressed air to remove the Chamber Base
[10](10).
Fig. 12
• Remove the O-ring (I.D 94.5) [7](7) from the Chamber Base [10](10).
• Push in the Piston Ass'y [15](15) from Blade Guide (A) [70](70) side to the Cylinder [5](5) side to remove
it.
• Remove the Hex. Socket Hd. Bolt M5 [64](64) from the Nose [17](17).
Fig. 13
• Move the Chamber Base [10](10) from the Cylinder [5](5) contact surface to the Nose [17](17) side and
secure the Cylinder [5](5) and Chamber Base [10](10) with tape as shown below.
Fig. 14
[10](10)
Temporarily tighten the Nylock Bolts
M6 [11](11) so that the threaded
portion is shown 3.5 to 6.5 mm.
[10](10)
Reduction valve set
[64](64)
Tape
-14-
Tip shape
[17](17)