System Repair - Komatsu 830E Shop Manual

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 lubri-
cate or seal any AC connections.
NOTE: To help prevent air, moisture or debris from
entering an open system, cap or plug open lines,
fittings, components and lubricant containers. Keep all
connections, caps, and plugs clean.
SYSTEM CLEANING
When performing repairs on air conditioning compo-
nents, a thorough inspection should be performed.
Inspect the parts that have been removed. If they con-
tain any loose or foreign material, the rest of the sys-
tem should be checked for the source of the material.
Only SAE and/or Mobile Air Conditioning Society
(MACS) approved flushing methods with the appro-
priate refrigerants are to be performed when
removing debris from the system. Other methods
may be harmful to the environment, as well as air
conditioning components.
M9-18
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. When grommets or clamps are
used to prevent line vibration, be certain these are in
place and secured.
It is important to always torque fittings to the
proper torque. Failure to do this may result in
improper contact between mating parts and leak-
age may occur. Refer to the following torque chart
for tightening specifications.
Fitting Size
6
8
10
12
Installation torque for the single M10 or 3/8 in. cap-
screws securing the inlet and outlet fittings onto the
compressor ports is 11 - 25 ft.lbs. (15 - 34 Nm).
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
Foot Pounds Newton Meters
10 - 15 ft.lbs. 14 - 20 Nm
24 - 29 ft.lbs. 33 - 39 Nm
26 - 31 ft.lbs. 36 - 42 Nm
30 - 35 ft.lbs. 41 - 47 Nm
05/02 M09010