ASAHI AV VALVES Installation Operation and Maintenance Manual
Butterfly Valves Type57L-IS (Lug style) 13
<< Disassembly >>
1) Drain fluid completely from the pipeline.
2) Leave the valve slightly opened.
3) Loosen the connecting bolts and nuts.
4) Remove the valve from the pipeline.
5) To remove handle , first take off the cap  by using screw driver (–)
and release bolt  by using socket wrench, then pull up the handle 
while holding handle lever .
6) To take off locking plate , release 4 self-tapping screws  by using
screw driver (+) and take off stem holder .
7) Loosen set bolt  for gear box  and pull off the gear box upward with
8) To take off stem holder . Release 4 tapping screws  by using screw
Lever & Gear Type
9) Hold flat surface of Stem  with vise and pull off valve body .
10) (A) Set the valve body  on square lumbers at edges of valve body on the
press and put a lumber on the disc .
Operate the press slowly and push disc  and seat  out if the valve body .
(B) Set the valve body  on square lumbers at edges of valve body and put a
circular stick on the disc .
Strike the circular stick with a hammer and remove disc  and seat  out of
the valve body .
11) Set the disc  parallel to the working desk to half opened position. Push the seat , and remove the disc .
12) Remove the retaining ring  and the O-ring(C)  from the stem .
<< Assembly >>
1) Put the O-ring(C)  onto the stem .
2) Before starting assembly, grease (Silicone) should be spread on the top and bottom disc , the stem hole of the
seat  and the stem O-ring(C) .
3) Insert the retaining ring  into the upper side slot of the seat . The upper side slot of seat  has larger
stem hole than lower side.
- Make certain tabs are properly aligned. Both upper and lower retaining rings  are identical.