- Off-Highway Truck/Tractor
- 794 AC (S/N: MN51-UP; MT51-UP)
- MT4400D AC (S/N: MH41-UP; MT41-UP)
- Unit Rig Mining Truck
- MT3300 (S/N: SE21-UP)
- MT3700 (S/N: SE31-UP)
- MT4400 (S/N: SE41-UP)
- MT3700 (S/N: SE31-UP)
Introduction
This Special Instruction provides information to install an improved cab blower housing assembly on the machines listed above.
Do not perform any procedure in this Special Instruction until you have read the information and you understand the information.
Safety Section
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Personal injury or death can result from improper lifting or blocking. When a hoist or jack is used to lift any part or component, stand clear of the area. Be sure the hoist or jack has the correct capacity to lift a component. Install blocks or stands before performance of any work under a heavy component. Approximate weights of the components are shown. Clean all surfaces where parts are to be installed. |
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When it is necessary to work under the machine with the body (bed) raised, attach the body (bed) retaining cables to the rear tow points. Install the rear tow point pins through the ends of the retaining cables. Failure to properly secure the body (bed) may result in personal injury or death. |
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Personal injury can result from working with cleaning solvent. Because of the volatile nature of many cleaning solvents, extreme caution must be exercised when using them. If unsure about a particular cleaning fluid, refer to the manufacturer's instructions and directions. Always wear protective clothing and eye protection when working with cleaning solvents. |
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Protect yourself and others; read and understand this warning. Fumes and gases can be dangerous to your health. Ultraviolet rays from the weld arc can injure eyes and burn skin. Electric shock can kill. Read and understand the manufacturer's instruction and your employer's safety practices. Keep your head out of the fumes. Use ventilation, exhaust at the arc, or both, to keep fumes and gases from your breathing zone and the general area. Wear correct eye, ear and body protection. Do not touch live electric parts. Refer to the American National Standard Z49.1, "Safety in Welding and Cutting" published by the American Welding Society, 2501 N.W. 7th Street, Miami, Florida 33125: OSHA Safety and Health Standards, 29 CFR 1910, available from U.S. Dept. of Labor, Washington D.C. 20210. |
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The Power Train Electric Drive System will contain hazardous voltage levels during machine operation and for a short period of time after engine shutdown. Do not remove any covers that will expose energized high voltage electrical components while the engine is operating. Any type of maintenance on the following components can only be performed after the Power Train Electrical System Service Shutdown procedure has been followed:
Failure to follow these instructions could result in personal injury or death. |
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In order to prevent damage to components, the power train high-voltage system must be shorted to the cabinet ground before welding anywhere on the truck. |
Required Parts
| Required Parts List | |||
| Item | Qty | Part | Description |
| 1 | 1 | Blower Housing | |
| 2 | 1 | Motor Plate | |
| 3 | 1 | Motor | |
| 4 | 1 | Wheel | |
| 5 | 3 | Screw | |
| (1) | |
Installation Procedure
- Drill extra three holes (A) on the bottom of blower housing (1). Refer to locations and dimensions shown in Illustration 1.
Note: Skip this step if the holes at the indicated locations are already drilled.
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Illustration 2 g06090221 (2) 493-7745 Motor Plate
(G) Four slots of size 9.5 X 24.4 (±3 tolerance)
(H) Angle 45 ± 1/2 degrees
(J)27.7 ± 3.0 mm (1.09 ± 0.12 inch) - Drill four slots (G) on motor plate (2). Refer to locations and dimensions shown in Illustration 2.
Note: Skip this step if 493-7748 Motor is used, since 493-7748 Motor is sealed does not need vent holes.
- Locate the former
83426A fan wheel/housing assembly that needs to be replaced inside the cab. Discard the part. - Disconnect all electric wires/connectors going to the fan assembly.
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Illustration 3 g06090223 (K) 454-8915 Ring
(L)6C-9131 Tapping Screws - Remove the former motor/fan/plate subassembly from the old housing by removing the three tapping screws (L). Discard the parts.
- Remove ring (K) from the old fan housing in the truck. Save the ring (K). Refer to Illustration 3.
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Illustration 4 g06090224 (M) 432-2916 Resistors
(N)5P-7162 Screws
(1)493-7746 Blower Housing
(2)493-7745 Motor Plate
(3)493-7748 Motor - Remove resistors (M) from the old fan housing. Remove and discard the old fan housing. Install resistors (M) on new blower housing (1) using the existing screws (N).
- Install motor plate (2) to motor (3) using existing hardware. Refer to Illustration 4.
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Illustration 5 g06090280 (3) 493-7748 Motor
(4)432-2892 Wheel - Install wheel (4) to motor (3).
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Illustration 6 g06090282 (1) 493-7746 Blower Housing
(2)493-7745 Motor Plate
(3)493-7748 Motor
(4)432-2892 Wheel
(5)5P-7162 Screws - Pre-install new wheel (4), motor (3), and motor plate (2) to new blower housing (1) using three screws (5). Spin wheel (4) inside blower housing (1) to ensure that wheel (4) spins freely. Remove new wheel (4), motor (3), and motor plate (2) from blower housing (1).
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Illustration 7 g06090228 (K) 454-8915 Ring
(1)493-7746 Blower Housing - Install blower housing (1) along with ring (K) retained in Step 6 to the cab and ensure that ring (K) is positioned properly.
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Illustration 8 g06119181 (1) 493-7746 Blower Housing
(2)493-7745 Motor Plate
(3)493-7748 Motor
(4)432-2892 Wheel
(5)5P-7162 Screws - Install new wheel (4), motor (3), and motor plate (2) to blower housing (1) using screws (5).
- Reconnect all wiring.
- Turn on the new fan system (24V) and check that fan system works properly without unusual noises. Check/re-install the system in the event of unusual noises.
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| Illustration 1 | g06090220 |
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(1) (A) Three holes of diameter (B) (C) (D) (E) (F) | |
