Johnston VT551 Maintenance Section page 57

VT550 - Maintenance
9. Remove and inspect the
low pressure seal (50) and
replace if necessary.
12. Using needle nose
pliers, remove the spring
tensioning caps (34), valve
spring (35), valve plate (36)
from the valve casing (29)
Using a valve extractor
(99.061) to remove the
valve seat (37) from the
valve casing (29).
15. Install the seal case (39)
with O Rings (40) into the
valve casing (29)
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10. Turn over intermediate
casting (48) Remove
and inspect the high
pressure seal (31) and the
support ring (32) replace if
necessary.
13. Inspect the valve seat
(37) and valve seat (36) for
signs of wear or cavitation
and replace as necessary.
16. Install the support ring
(32) and the high pressure
seal (31) into the intermedi-
ate plate (48)
11. Remove the seal case
(39) from the valve casing
(29) and inspect both O
Rings (40) for wear.
14. Install the inlet valve
assembly (34 – 38) back
into the valve casing.
Ensure the "f ngers" of the
spring tensioning cap (34)
DO NOT obstruct the cross
bore in the valve casing
(29).
17. Lubricate the low
pressure seal (50) and
install into the intermediate
casing (48).
Chapter - Water System
10:11