HYDRAULIC AND AIR SYSTEMS 2250 SERVICE/MAINTENANCE MANUAL
2-32
Published 11-06-15, Control # 040-13
9. Remove three self-tapping screws (3) that secure the
purge valve housing to the end cover. Pull the purge
valve housing out of the end cover. Remove the three o-
rings (5,6 & 7) from exterior of purge valve housing.
10. Purge Valve Disassembly:
In most cases a flat exhaust cover (30) is used. This
cover should be left intact while servicing the purge
valve housing. If an extended type exhaust cover is in
used, the exhaust cover must be carefully peeled off the
purge valve housing. Use a thin flat blade to pry the
exhaust cover off, taking care not to damage the potting
material (RTV sealant) under the cover.
To remove the piston from the purge valve housing
requires a special socket or a twelve point socket to hold
the head of the purge valve bolt (31).
a. Remove nut (4) from the bottom of purge valve
housing. Use wrench and socket to hold the head of
bolt (31). Remove the diaphragm washer (32), and
the diaphragm (2), and purge valve (11) from purge
valve housing.
b. Remove bolt (31) from opposite end, then the purge
piston (33), return spring (13) and two O-rings (10
and 14), one on the outside diameter and the other
in the inside of purge piston.
NOTE: Do not attempt to remove the heater and
thermostat, as it will be damaged during the
removal process and is not available as a service
part. If the heater and thermostat are defective,
replace the entire purge valve housing which
includes these items.
11. Remove remaining six cap screws (16), lock nuts (19)
and twelve special washers (17) that secure the end
cover to the housing (24). Separate the end cover and
desiccant cartridge (22) from the housing.
12. Remove end cover to outer housing o-ring (23).
13. Do not remove the safety valve from the end cover
unless it has been proven defective. If replacement is
required, apply thread sealant or teflon tape on the
threads of the replacement valve and torque to 120 to
400 in/Ibs (14 to 45 Nm).
14. Place a strap or chain wrench around the desiccant
cartridge (22) so that it is approximately 2 to 3 in (50,8 to
76,2 mm) away from the end cover. Rotate cartridge
counterclockwise until it separates from the end cover.
15. Remove the desiccant cartridge o-ring (21) from the end
cover.
Cleaning and Inspection
1. Using mineral spirits or an equivalent solvent, clean and
thoroughly dry all metal parts.
2. Inspect the interior and exterior of all metal parts that will
be reused for severe corrosion, pitting and cracks.
3. Superficial corrosion and or pitting on the exterior
portion of the upper and lower body halves is
acceptable.
4. Inspect the bores of both the end cover and the purge
valve housing for deep scuffing or gouges.
5. Make certain that all purge valve housing and end cover
passages are open and free of obstructions.
6.
reinspect the pipe threads in the end cover. Make certain
they are clean and free of thread sealant.
7. Inspect purge valve housing bore and seats for
excessive wear and scuffing.
8. Inspect the purge valve piston seat for excessive wear.
9. Inspect all air line fittings for corrosion. Clean all old
thread sealant from the pipe threads.
10. All o-rings removed should be discarded and replaced
with new o-rings provided in appropriate kit(s). Any
component exhibiting a condition described above steps
should be replaced.
Assembly
Before assembly, coat all o-rings, o-ring grooves, and bores
with a generous amount of barium base lubricant.
1. Purge Valve Housing:
a. Install O-ring (14) in groove on outside diameter of
the purge piston. Place the return spring (13) in the
purge valve housing. Place o-ring (10) into recess in
the bore of purge piston. reinstall bolt (31) into
inside diameter of the purge piston. Insert purge
piston (33) into inside diameter of the spring (13).
Push purge piston into the bottom of piston housing.
b. While depressing purge piston with the wrench,
install following parts over the purge valve bolt (31)
from the opposite end of the purge valve housing;
the purge valve (11) with rubber side first, followed
by the diaphragm (2) diaphragm washer (32) or the
flat washer and the lock nut (4).
Torque the purge valve nut and bolt (4 and 31) to
between 60 to 80 in/Ibs (7 to 9 Nm).
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