4.4
Assembly
It is advisable to replace seats and seals if complete
disassembly and reassembly become necessary. Refer to the
Repair Kit chart (see
Table 1
). Although it is not required,
a lubricant, compatible with the tank car commodity, may
be applied to the seats, seals, ball and stem to facilitate
assembly and for ease of initial operation.
1. Clean all valve components if not done previously.
2. Re-inspect all components for damage before
reassembling the valve. Look for damage to the sealing
areas of the stem, body and insert; and look for wear in
the bearing areas. Replace any damaged parts.
3. Carefully clean and polish the ball (3) sealing surface: It
should be free of all scratches and grooves.
4. If the ball is slightly damaged, it may be possible
to smooth the sealing surface with crocus cloth or
equivalent. If deep scratches are present, replace the ball.
5. With the body insert side facing up, slide one valve
seat (7) sideways into the body (1) to below the stem
bore, and tilt it into place so that the proper surface (see
Figure 3
) will be adjacent to the ball (3), being careful
not to cut or scratch the seat.
NOTE:
For Barrier seat assembly, (see
Section 4.6.2
).
Figure 3 Proper Seat and Ball Orientation
6. From inside the body (1), insert the one lower stem seal
(70), the secondary stem seal (71), and the second lower
stem seal (70) into the stem bore (see
Figure 8
).
7. Insert the stem (5) through the body cap end of the
body (1), being careful not to scratch the stem sealing
surface; and press it gently up into the stem bore until
resistance is felt from the thrust bearing.
8. Hold the stem in place from the bottom and insert the
packing (69) (see
Figure 4
for proper v-ring orientation),
over the stem (5).
Figure 4 Proper V-ring Orientation
9. Place the compression ring (9) on the stem (5) and fit
the compression plate (10) over stem (5) and bonnet
studs (14). Place one stop bushings (50) over each
bonnet stud (see
Figure 5
for proper orientation).
10. Place indicator stop (32) over the stem (5). A tamper-
proof pin in the stem will allow the indicator stop onto
the stem only one way. At this point, the stem with
the indicator stop mounted and located between stop
bushings (39) is positioned so that a counterclockwise
rotation of the stem will open the valve.
NOTE:
For valves with the “FO” option, (see Identification
Plate), the indicator stop (32) is marked “FO”. When placing
the indicator stop over the stem, “FO” marking must be facing
up. At this point, the stem with the indicator stop mounted
and located between stop bushings (39) is positioned so
that a clockwise rotation of the stem will open the valve.
11. Place retaining ring (34) over the stem and into the
groove on the stem.
12. Place two disc springs (76) over each bonnet stud (14),
(see Figure 5 for proper disc spring orientation). Place a
flat washer (77) over each bonnet stud (14).
Figure 5 Proper Disc Spring Orientations
Uncompressed
Compressed
18
14
77
76
IMO
4/19
6
IMO-R20 EN
