System Repair; Tracer Dyes; Soap And Water; Hoses And Fittings - Komatsu 930E-2 Shop Manual

Tracer dyes

Tracer dyes are available that can be added to the
system as refrigerant is added. The system is then
operated to thoroughly circulate the dye. As refrigerant
escapes, it leaves a trace of the dye at the point of
leakage, which is then detected using an ultraviolet
light ("black light"), revealing a bright fluorescent glow.

Soap and water

Soap and water can be mixed together and applied to
system components. Bubbles will appear to pinpoint
the specific location of leaks.
After determining the location or source of leak(s),
repair or replace leaking component(s).
NOTE: The length of the hose will affect the refrigerant
capacity. When replacing hoses, always use the same
hose length, if possible.
Before system assembly, check the compressor oil
level and fill to manufacturer specifications.
M9-16

SYSTEM REPAIR

The following service and repair procedures are not
any different than typical vehicle service work. How-
ever, AC system components are made of soft metals
(copper, aluminum, brass, etc.). Comments and tips
that follow will make the job easier and reduce unnec-
essary component replacement.
All of the service procedures described are only
performed after the system has been discharged.
Never use any lubricant or joint compound to
lubricate or seal any AC connections.
NOTE: To help prevent air, moisture or debris from
entering an open system, cap or plug open lines,
fittings or components and lubricant containers until
connected and as soon as they are disconnected.
Keep all connections clean (also caps and plugs
used) so debris can't enter accidentally.

Hoses and Fittings

When replacing hoses, be sure to use the same type
and ID hose you removed. When hoses or fittings are
shielded or clamped to prevent vibration damage, be
sure these are in position or secured.
Lines
Always use two wrenches when disconnecting or con-
necting AC fittings attached to metal lines. You are
working with copper and aluminum tubing which can
kink or break easily. Tube O-ring type fittings require
only 18 ft. lbs. (24.4 N.m) of torque for correct sealing.
When grommets or clamps are used to prevent line
vibration, be certain these are in place and secured.
Expansion Valve
When removing the expansion valve from the system,
remove the insulation, clean the area and disconnect
the line from the receiver-drier. Detach the capillary
(bulb) and external equalizer tube (if present) from their
mounting locations. Remove the expansion valve from
the evaporator inlet. Expansion valve service is limited
to cleaning or replacing the filter screen. If this is not
the problem, replace the valve. Secure the capillary
and equalizer, if used, to clean surfaces and replace or
attach any insulating material.
Air Conditioning System
for HFC 134a Refrigerant
M09010 6/97