Chevrolet Light Duty Truck 1973 Service Manual page 80

1A-54 HEATER A N D AIR C O N D IT IO N IN G
the hose as shown in Figure 55. This should loosen
the hose so that it may be worked off the fitting.
2. Cut off slit end of hose.
Use only approved refrigeration
CAUTIO N :
hose. Never use heater hose. Use extreme care
not to nick or score the sealing beads when
cutting off the hose. Cutting the hose lengthwise
may result in this problem.
Installation
1. Coat tube and hose with clean refrigeration oil.
2. Carefully insert hose over the three beads on the
fitting and down as far as the fourth, or locating
bead. Hose must butt against this fourth bead.
Use no sealer o f any kind.
CAUTIO N:
3. Install clamps on hose, hooking the locating arms
over the cut end of the hose.
4. Tighten the hose clamp screw to 35-42 in. lbs.
torque. DO NOT RETORQUE. The clamp screw
torque will normally decrease as the hose conforms
to the force of the clamp. The screw should be
retorqued only if its torque falls below 10 in. lbs. In
this case, retorque to 20-25 in. lbs. Further
tightening may damage the hose.
MAKE ANGULAR CUT
FOR HOSE REMOVAL
HOSE CLAMP
HOSE
Fig. 55 -Hose Clamp Connections
HOSE CLAMP
LOCATING
BEAD
HOSE
SEALING
LOCATING
BEADS
BEAD
REPAIR OF REFRIGERANT LEAKS
Any refrigerant leaks found in the system should be
repaired in the m anner given below:
Leaks at " 0 " Ring Connection
1. Check the torque on the fitting and, if too loose,
tighten to the proper torque. Always use a backing
wrench to prevent twisting and damage to the "O "
ring. Do not overtighten. Again leak test the joint.
2. If the leak is still present, discharge the refrigerant
from the system as described under "Evacuating
and Charging Procedures."
3. Inspect the "O " ring and the fitting and replace if
damaged in any way. Coat the new "O " ring with
clean refrigeration oil and install carefully.
4. Retorque the fitting, using a backing wrench.
5. Evacuate, charge and check the system.
Leaks at Hose Clamp Connection
1. Check the tightness of the clamp itself and tighten
if necessary. Recheck for leak.
2. If leak has not been corrected, discharge the system
and loosen clamp and remove hose from connec­
tion. Inspect condition of hose and connector.
Replace scored or damaged parts.
3. Dip end of new hose in clean refrigeration oil and
carefully reinstall over connector. Never push end
of hose beyond the locating bead. Properly torque
the clamp.
4. Evacuate, charge and check the system.
Compressor Leaks
If leaks are located around the compressor shaft seal or
shell, replacement of necessary seals should be made as
outlined under "Compressor" in the Overhaul Manual.
NOTE: A slight amount of oil leakage past
the compressor front seal is considered
normal.
REFRIGERANT HOSE FAILURE
After a leak or rupture has occurred in a refrigerant
hose, or if a fitting has loosened and caused a
considerable loss of refrigerant and oil, the entire system
should be flushed and recharged after repairs have been
made. If the system has been open to atmosphere for
any prolonged period of time the receiver-dehydrator or
accumulator should be replaced.
Because of the length of the hoses on these systems, hose
leaks may be repaired using the following procedure:
1. Locate the leak. This may require removing the
body inner side panels to gain access to the hoses
(Overhead Systems).
2. Discharge the system.
3. Cut out the leaking portion of the hose, making
LIGHT DUTY TRUCK SERVICE MANUAL