Disassembly Procedures - U.S. Divers Impulse Service & Repair Manual

Impulse Second Stage Service & Repair Manual
Fig. 1 - Boxtop Removal

Disassembly Procedures

NOTE: Before performing any disassembly, refer to the
schematic drawing, which references all mandatory replace-
ment parts. These parts should be replaced with new, and
must not be reused under any circumstances - regardless of
the age of the regulator or how much use it has received
since it was last serviced.
CAUTION: Use only a plastic or brass O-ring removal tool
(P/N 9440-22) when removing O-rings to prevent damage to
the sealing surface. Even a small scratch across an O-ring
sealing surface could result in leakage. Once an O-ring
sealing surface has been damaged, the part must be re-
placed with new. DO NOT use a dental pick, or any other
steel instrument.
1. Slide back the hose protector(10) to expose the IP hose fitting.
2. While holding the hex nut(11) of the second stage secure with
a 22mm open end wrench, apply a 11/16" open-end wrench
to the female fitting of the IP hose(8). Turn the fitting counter-
clockwise to loosen and remove the hose from the second
stage. Remove the O-rings(7&9) from the hose and discard.
Set the hose aside.
3. Carefully snip the plastic mouthpiece clamp(16) and remove
the mouthpiece(15) from the box bottom. Inspect the mouth-
piece to ensure it is free of any tears or cuts that may cause
leakage of water into the second stage or other discomfort.
Discard or set the mouthpiece aside to be reused, depending
on its condition.
4. While holding the second stage secure, gently twist the
boxtop(1) 45° counter-clockwise to disengage from the box
bottom(6). (See Fig. 1.) Pull the boxtop straight away from
the box bottom to remove, and press out the purge cover(2).
5. Securely mate both pins of the Circlip/ Retaining Ring Tool
(P/N 1078-46) into two opposite holes of the retaining ring(3).
While applying even downward pressure to prevent slippage
of the tool, carefully turn the retaining ring counter-clockwise
to loosen and remove.
6. Lift out the thrust washer(4) and diaphragm(5). Closely
inspect the diaphragm to ensure that it is perfectly round and
free of any tears, deterioration, or other damage. If deteriora-
tion or damage is found, discard the diaphragm and do not
attempt to reuse.
7. Apply a 22mm open end wrench to the hex nut, and turn
counter-clockwise to loosen and remove from the inlet end of
the valve body(23).
8. Turn the adjustment knob(32) completely out counter-clock-
wise until it stops. This will hold the retaining pin(24) in
place when the valve module is removed from the box bottom.
9. While holding the box bottom secure and the lever(26) com-
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© 1997 U.S. Divers Co., Inc.