MCi Crusader II 1989 Maintenance Manual page 177

Date 1-1-89
Page ·_. __
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MC-9 MAINTENANCE MANUAL
ASSEMBLY
Prior to assembly. wash all metal parts thoroughly using a
quality commercial solvent (such as mineral spirits). Inspect
all parts for wear or damage and replace any parts that fail
this visual inspection.
1. Refer to figure 4-62. Place the purge valve spring
into
the cavity in the center of the top side of the end cover.
2. Lubricate the piston O-ring with a barium base lubri-
cant and install the O-ring on the purge valve piston and
place the piston inside the spring installed in step 1.
3. Turn the cover over on a flat. clean surface (making
sure the purge valve piston and spring remain in proper
position). Compress the spring by pushing down on the
cover and align the square shank of the purge valve piston
into the mating hole in the cover.
4. Place the washer. diaphragm retainer. diaphragm and
purge valve onto the purge valve capscrew.
5. Install the purge valve capscrew with parts on it into
the exhaust cover and tighten to 30-40 lb-in (3.4-4.5 Nm)
torque.
6. Install the safety valve (if removed) and tighten to 120-
400 lb-in (13.5-45.0 Nm) making surethatthe exhaust hole is
pointed downward. when the dryer is installed.
7. Install the thermostat(if removed). Refer to instructions
pertaining to thermostat installation. below.
8. Place the sealing ring on the bottom of the desiccant
cartridge. Attach the cartridge to the plate (smooth side of
plate opposite cartridge)
with
four socket head capscrews
and-lock washers. Tighten to 80-100 lb-in (9.0-11.3 Nm)
torque.
9. Lubricate and install the two sealing rings in the
recesses of the end cover. Use a barium base lubricant.
10. Install the check valve assembly into the cover mak-
ing sure the holes in the metal stamping are facing up and
the tang on the check valve assembly fits into the mating
recess in the cover.
1 1. Place the desiccant cartridge and sealing plate
assembly onto the cover taking care not to displace the
seating rings. The large hole in the sealing plate must line up
with the check valve and the spirol pins in the sealing plate
must enter the corresponding holes in the end ccver.
12. Lubricate the outer sealing ring with barium base
lubricant and install on the sealing plate. Place the housing
of the air dryer over the desiccant cartridge (lining up the
marks on the housing and cover made prior to disassembly)
and retain with eight¾" hex head bolts. special washers and
crown nuts. Tighten to 270-330 lb-in (30.7-37.5 Nm).
NOTE: If the 31.-24
x
2 1 h" bolts require
replacement, insure that the replacement
bolts are grade 5 minimum. Use of infe-
rior bolts can compromise
the
integrity
of the air dryer and lead to premature
failure.
13. Install the assembled AD-4 air dryer on the coach by
sliding it into the mounting brackets until the mounting
bracket hook catches under the lip of the cover arid tighten
the mounting bracket bolts to the 70-85 lb-in (7.9-9.6 Nm).
14. Reconnect the three air lines to the proper port
OI)
the
cover (identified during disassembly).
15. Reconnect the thermostat and heater
wire
and place
the boot in position to protect the connection by forcing it
over the knob on the plastic cover. ·
16. Install the dryer shroud with the retained mounting
hardware.
17. Test the air dryer as outlined under Mair:itenance.
above.
THERMOSTAT REPAIR
1. Refer to figure 4-60. Remove nut (1 ), then lock washer
(2) nut (3), washer (4) and O-rings
(5).
Discard O-rings and
retain other parts.
2. Remove and retain the four Phillips head screws 16)
and cover
17).
3. Remove and discard gasket ( 10).
4. Remove and retain spacer (11 ).
5. Cut uninsulated thermostat wire at Point
B
(figure 4-
62). remove and discard thermostat and terminal assembly
(12).
6. Clean remaining wire attached to heater terminal.
7. Clean thermostat .. pocket" in end cover (9).
NOTE: Steps 8 thru 16 are for thermostat
assembly.
a.
Cut the uninsulated lead of the new thermostat at
point A (figure 4-60).
9. Install the thermostat in the end cover pocket and
position the uninsulated leads next to each other.
10. Using a soldering heat sink, clamp the uninsulated
leads at point B (figure 4-60) and solder the leads with
straight rosin core solder. DO NOT USE ACID CORE
SOLDER as corrosion can result Clean excess solder
off end cover.
11. Install thermostat terminal (12) in cover (6).
12. Install O-ring (5), washer 14) and nut (3). Tighten nut to
20-30 lb-in (2.3-3.4 Nm) torque. Then install lock washer (2)
and nut (1) finger tight to allow for reconnection of electrical
wire when reinstalled on coach.
· 13. Install spacer (11) over thermostat (12).
14. Install gasket (7) and thermostat cover (6) and secure
thermostat cover to end cover (9) using screws (7) and lock
washers (8).
15. Tighten to 30-40 lb-in (3.4-4.5 Nm) torque.
16. Test the thermostat as follows:
a. At a temperature above 90°F (32"C). check the
resistance between the thermostat terminal (2) and end
cover (9). Resistance should be 1000 ohms or greater. If not.
check for solder short
b. Chill the end cover assembly to 40°F (4°C) and
check resistance again. Resistance should be 4-7 ohms.