21
TC-003001-30 / Rev 01
Feb-02
3.
Inspect the seats, paying careful attention to the insert sealing surfaces. Reject and replace all seats with
dings, scratches, or any other physical defects. Install the O-rings and the backup ring. The back-up ring
should be on the head side of the seat as shown in Fig. 10. Apply lubricant until completely covering the
O-rings and back-up ring.
Figure 10 – 370D6 Seat Assembly
4.
Install the O-rings and back-up ring (as applicable) to the tailpiece and cover. If the valve size and class
require back-up rings, those shall be positions above the O-ring towards the flange of the part as shown in
detail J and detail K of Fig. 1 and Fig. 2.
5.
Install the radial bearings on the stem using a bearing tool shown in Fig. 11. The lower bearing is wider
than the upper bearing. Both bearings shall fit into the designated grooves.
Figure 11 – Stem Bearing Installation
Using the same tool, install the O-rings. Install the back-up rings above the O-rings on the stem gear side, as shown
in Fig. 12.
Figure 12 – Stem O-ring Installation