Hale MG - Manual (Page 108)

Muscle Pumps
5-44
17) Attach hoses or tubing to inlet
fittings of the drain valve.
18) Test operate apparatus and check
drain valve for leaks.
19) Return apparatus to normal
operation.
c. Type DV7 Drain Valve:
(Refer to figure 6-23)
If the type DV7 drain valve is leaking
the seals must be replaced. Replace
the seals using the following
procedures:
1) Place apparatus out of service in
accordance with department
procedures.
2) Open all drain valves to make
sure all pressure is relieved from
the pump.
3) Gain access to the backside of the
valve body where the grease
fitting is located. Remove any
tubing or hoses that interfere with
valve disassembly. Remove the
retaining ring from the valve
stem.
4) Unscrew the valve stem
completely from the valve body.
5) Remove the retaining ring that
holds the seat and seat retaining
washer on the valve stem.
6) Remove the seat retaining washer
from the stem with the thrust
washers.
7) Remove the seat from the seat
retaining washer.
8) Remove the knob from the stem
by loosening the set screw in the
knob.
9) Clean all parts and check for
excessive wear or pitting. Check
to make sure the sealing surfaces
of the inlet fittings are clean and
not pitted.
10) Install a new seat in the seat
retaining washer.
11) Install a thrust washer on the stem
then install the seat retaining
washer and the other thrust
washer. Secure these parts to the
stem using the retaining ring.
12) Install the operating knob on the
stem and secure in place with the
setscrew.
13) Carefully thread the stem assembly
into the valve body.
14 Lock the stem assembly in the
body using the retaining ring.
15) Attach hoses or tubing to inlet
fittings of the drain valve.
16) Test operate apparatus and check
drain valve for leaks.
17) Return apparatus to normal
operation.