GAUGE-PRESSURE 4655881 - Caterpillar

Introduction
This Special Instruction provides helpful tips in order to install a door which blends the air in the HVAC. The 177-6732 Door Assembly is being replaced by 320-1457 Door Assembly . This is located within specific HVAC units.Note: This door assembly is used in various machines such as wheel loaders, forestry products, and excavators. The replacement 320-1457 door assembly has been upgraded with a stronger nylon material in order to prevent breakage. Note: Removal of the HVAC unit varies depending on your model. Wheel loaders will require the HVAC unit to be removed from the cab completely. (Use self-sealing coupling to disconnect refrigerant lines.) With models such as forestry products, the HVAC unit can be tilted back after removing the mounting bolts.Procedure For Replacing The Door As
Illustration 1 g01443068
This photo shows a typical control knob for the air mix door.
While the machine is running, turn the knob (1) for the temperature to the center position. This will position the actuator correctly for assembly of the new air mix door. This is shown in the photo. Turn the machine OFF.
Illustration 2 g01458475
Remove the HVAC unit from the cab on Wheel Loaders. Remove the filter housing, and the housing for the air distribution from the HVAC unit on Excavators and Forest Products. Remove the mounting bolts. The HVAC unit can be tilted forward on Excavators and Forestry Products. This will give you access to the housing that contains the air mix door. See illustration 2.
Illustration 3 g01443093
The HVAC unit on Excavators and Forestry Products can be tilted forward. The HVAC unit on Wheel Loaders can be placed on the left side or the right side. Remove the screw (3) and the linkage arm from the shaft of the 177-6732 Door As . The screw is located on the bottom of the HVAC unit. See illustration 3.
Illustration 4 g01456745
Illustration 5 g01456741
Air mix door
Remove the actuator (2) to the 177-6732 Door As (5). Remove all screws that connect the top and bottom halves of the HVAC casing and disassemble the unit that includes the broken door. See illustration 4 and 5.
Carefully inspect the two halves of the HVAC casing for irregularities before reassembly. Pay special attention to the tongue and the groove. This is located at the edge of the inner walls. Use a sharp knife to remove any excess plastic material. This will ensure a good fit. See illustrations 6 and 7.
Illustration 6 g01457289
This photo shows poor alignment.
Illustration 7 g01457292
This photo shows proper alignment.
Remove the screw and the washer from the shaft on the 320-1457 Door As . The screw and the washer will be reinstalled later.Note: When you remove the screw, support the door near the screw. See illustration 8.
Illustration 8 g01520849
(A) Remove the washer and the screw. (B) The area of the door that should be supported
Install the new 320-1457 Door As into the bottom half of the HVAC unit. See illustration 5.
Reinstall the top half of the unit. Check for proper alignment of the tongue and groove joints. Check the inner