CASE-TRANSMISSION 1752518 - Caterpillar

Note: Replace dryer (2) annually. Dryer (2) should also be replaced whenever the system is opened.Disassembly and Assembly
Illustration 2 g01520434
In-line dryer without quick disconnects (4) Inlet hose without air conditioner quick disconnect (5) Dryer (6) Outlet hose without air conditioner quick disconnects
Illustration 3 g03549076
320-0562 Refrigerant Dryer As (7) Dryer (8) Air conditioner orifice assemblyNote: Every 2 years replace dryer (5) and (7) . Dryer (5) and (7) should also be replaced whenever the system is opened.Before removing the dryer, perform the following steps in order to diagnose the problem
Check the following components for blockages:
Condenser
Evaporator
Fresh air filters
Check the condition and the tension of the compressor drive belt.
Connect a manifold gauge set to the compressor. Refer to Testing and Adjusting, "Manifold Gauge Set (Refrigerant) - Install".
Operate the Air conditioning.
Operate the engine at 1400 rpm.
Place the air conditioning switch in the ON position.
Set the blower switch to the HIGH position.
Open all of the louvers in the cab.
Close the cab doors and close all of the cab windows.
Compare the pressures for the manifold gauge to the pressure ranges in Table 1 in order to ensure that the pressures are normal for the current ambient air temperature.
Table 1
Pressure Range (1)    
Ambient Air Temperature
C° (F°)     High Pressure Test Fitting
kPa (psi) (2) (3)     Low Pressure Test Fitting
kPa (psi) (4) (5)    
21°C (70°F)    
820 to 1300 kPa (120 to 190 psi)    
70 to 138 kPa (10 to 20 psi)    
27°C (80°F)    
950 to 1450 kPa (140 to 210 psi)    
70 to 173 kPa (10 to 25 psi)    
32°C (90°F)    
1175 to 1650 kPa (170 to 240 psi)    
105 to 210 kPa (15 to 30 psi)    
38°C (100°F)    
1300 to 1850 kPa (190 to 270 psi)    
105 to 210 kPa (15 to 30 psi)    
43°C (110°F)    
1450 to 2075 kPa (210 to 300 psi)    
105 to 210 kPa (15 to 30 psi)    
( 1 ) This table is only for reference.
( 2 ) Pressure may be slightly higher in humid conditions and lower in dry conditions.
( 3 ) With AC High-pressure Test Fitting is located near the Evaporator Inlet pressure reading will be 83 to 103 kPa (12 to 15 psi) lower.
( 4 ) Pressure before clutch disengagement.
( 5 ) With AC Low-pressure Test Fitting is located near the Evaporator Outlet pressure reading will be 14 to 21 kPa (2 to 3 psi) higher.
Check for frost at the dryer outlet.Note: Moisture on the drier outlet tube after the orifice is normal and this moisture does not indicate a failure with the dryer. Frost on the drier outlet tube after the orifice is an indicator of a low refrigerant charge.
If frost is indicated at the dryer outlet or if pressures are low, proceed to Step 8. Otherwise, proceed to Step 15.
Recover the refrigerant charge from the machine. Refer to Disassembly and Assembly, "Refrigerant System Recovery".
Record the amount of refrigerant and oil that is recovered from the Air Conditioner system.These