Chevrolet 10 Series 1968, Service Manual

Page: 57 / 713

HEATER AND AIR CONDITIONING 1A-26
If at any time when examining the compressor oil,
moisture is found or there is an indication of moisture
at the expansion valve needle, the receiver-dehydrator
should be replaced as follows (fig. 35):
NOTE: If the receiver-dehydrator is to be re ­
used, cap the inlet and outlet connections imme­
diately. When installing a receiver-dehydrator,
do not uncap the connections until the last possi­
ble moment.
Rem oval
1. Disconnect battery ground cable.
2. Purge the system.
3. Remove the inlet and outlet connections from the
receiver-dehydrator.
4. Remove the receiver-dehydrator mounting bolts and
carefully remove it.
5. Cap the system if the receiver-dehydrator will not
be replaced immediately. Cap the receiver if it
will be reused.
Installation
1. Place the receiver-dehydrator in position and re ­
place attaching bolts. Do not uncap the unit until
immediately before connecting lines.
2. Uncap any previously capped connections and con­
nect the fittings using new
“ Q”
ring seals, coated
with clean refrigeration oil.
3. Evacuate and recharge the system. If a new
receiver-dehydrator was installed, add one fluid
ounce refrigeration oil to the system.
4. Connect battery ground cable.
SIGHT GLASS REPLACEMENT
If damage to the sight glass should occur, a new sight
glass kit should be installed. The kit contains the sight
glass, seal and retainer. (See Figure 36)
1. Purge system.
2. Remove the sight glass retainer nut using a screw
driver and remove old glass and seal.
3. Install the new glass and seal and retainer nut, being
careful not to turn the nut past the face of the hous­
ing.
To do so may damage the
“ O ”
ring seal.
4. Evacuate and recharge the system.
EXPANSION VALVE
Removal
1. Disconnect battery ground cable and purge the
system.
2. Loosen the clamp retaining the high pressure line
to the bracket next to the expansion valve.
3. Disconnect the capillary bulb from the evaporator
outlet pipe. Disconnect the equalizer line from the
P.O.A. Cap the P.O.A. connector.
4. Disconnect the expansion valve inlet and outlet con­
nections and cap the lines.
5. Remove expansion valve to bracket mounting screw
and remove expansion valve.
Installation
1. Mount the expansion valve to the bracket.
2. Connect the inlet and outlet connections. Tighten
the inlet pipe clamp.
3. Connect the equalizer line to the P.O.A. and mount
the capillary bulb to the evaporator outlet pipe.
4. Connect battery ground cable. Evacuate and charge
the system. Check performance.
P.O.A. VALVE
Removal
1. Disconnect battery ground cable and purge the
system.
2. Remove evaporator oil bleed line and expansion valve
equalizer line. Cap the connections.
F ig . 36—Sight G lass Replacement
CHEVROLET TRUCK SERVICE MANUAL