Cashco DA2 - Positive Differential - Manual (Page 8)

IOM-DA2 8
Figure 4
Not supplied. Use any
bolt, washers (2) and
nut of same approximate
hole size.
17
19
16
13
E. Reassembly of the ITA:
1. When replacing the wiper seal (16), the wiper
seal (16) should be “performed” from the
factory. It will, however, require re form ing.
Reform the wiper seal (16) by press ing the
temporary assembly parts into the cage (19)
backwards as shown in Figure 4 (only ap-
plicable to composition diaphragm design).
The wiper seal (16) is best left in this position
overnight, but a min i mum of 30 minutes prior to
re as sem bly. Soaking in a bucket of hot water
will speed up the reforming process.
2. After reforming the wiper seal, remove parts
(13, 16, 17) from cage (19) and disassemble
the tem po rary assembly of Step 1. above.
3. Installation of dynamic side seal (27)
(See Figure 1):
a. Type OR:
1. Stretch o-ring seal (27.4) over lower
cir cum fer ence of piston-guide bear-
ing (13), tak ing care not to “cut” o-ring
seal (27.4). Using thumbs, work the
o-ring seal (27.4) up and into the
groove of the piston-guide bearing
(13). NOTE: A very slight amount
of fl uid and elas tomer compatible
o-ring lubricant is rec om mend ed as
an installation aid.
2. For metal diaphragm construction, in-
sert cam ber adjusting washer (17.2)
into cage (19) and allow to rest in the
bottom of the cage (19).
3. Position piston-guide bearing (13)
over upper end of cage (19) prop-
erly oriented. Using thumbs, evenly
press piston-guide bearing (13) into
the cage (19), ensuring not to “cut”
o-ring seal (27.4). Continue pressing
pis ton-guide bearing (13) until in ap-
proximate fi nal position.
b. Type CP:
1. Stretch o-ring energizer/seal (27.2)
over low er cir cum fer ence of piston-
guide bear ing (13), tak ing care not
to “cut” o-ring energizer/seal (27.4).
Using thumbs, work the o-ring en-
ergizer/seal (27.4) up and into the
groove of the piston-guide bear ing
(13). NOTE: A very slight amount
of fl uid and elas tomer compatible
o-ring lubricant is rec om mend ed as
an installation aid.
2. For metal diaphragm construction,
insert cam ber adjusting washer
(17.2) into cage (19) and allow to
rest in the bottom of the cage (19).
3. Position TFE cap seal (27.1) ring
with rectangular cross-section at
end of pis ton-guide bearing (13).
Stretch cap seal (27.1) over lower
end of piston-guide bear ing (13)
using thumbs to work the cap
seal (27.1) onto the piston-guide
bearing (13). DO NOT USE A
TOOL FOR THIS STEP. Continue
pressing cap seal (27.1) up wards
towards the groove until the cap
seal (27.1) “snaps” into the groove
of the piston-guide bearing (13).
4. Position piston-guide bearing (13)
over and into upper end of cage
(19) until the cap seal (27.1) edge
touches the upper lip of the cage
(19). While gently applying force
to press the piston-guide bushing
(13) into the cage (19), simultane-
ously use fi ngers to lightly press
the cap seal (27.1) inwards into the
groove of the pis ton-guide bearing
(13) until the cap seal (27.1) “slips
into” the cage (19). DO NOT USE
TOOLS, LUBRICANT, OR HEAVY
FORCE TO EN GAGE THE CAP
SEAL (27.1) INTO THE CAGE
(19).