- Off-Highway Truck/Tractor
- 777D (S/N: FKR1-UP)
Reference: SMAG, M0081060, "A New Refrigerant Accumulator is Now Available for Certain 777D Off-Highway Trucks"
Reference: SENR5664 , Air Conditioning and Heating R134a for all Caterpillar Machines, "Testing and Adjusting"
Reference: SENR5664, Testing and Adjusting, "Refrigerant Recovery"
Reference: Specifications, SENR3130, Torque Specifications
Reference: Testing and Adjusting , SENR5664 , Air Conditioning and HeatingRefrigerant System - Evacuate
Reference: Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide"
Introduction
Do not perform any procedure in this Special Instruction until you have read the information and you understand the information.
This Special Instruction outlines the procedures needed to replace an existing receiver dryer and relocate an A/C pressure switch from the A/C compressor to the receiver inlet coupling in 777D Off-Highway Trucks.
Refer to SMAG, M0081060, "A New Refrigerant Accumulator is Now Available for Certain 777D Off-Highway Trucks" for further information on replacing the accumulator.
Safety Section
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Personal injury or death can occur from not following the proper procedure or the recommended tooling. To prevent the possibility of injury or death, follow the established procedure using the recommended tooling. Personal injury or death can result when charging an air conditioning system with a liquid. The compressor will pump the refrigerant back into the charging cylinder with the possibility of rupturing (exploding) the cylinder. Do not operate the engine when charging with a liquid. Never charge liquid or gas through the discharge (high side of the system) with the engine running. Keep all other personnel either away from the machine or where they can be seen when working on the air conditioning system. |
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Personal injury can result from air conditioning system pressure. The air conditioning system will become a pressure system when charged. To avoid personal injury see the Air Conditioning and Heating Service Manual for instructions on charging the system. Personal injury or death can result from inhaling refrigerant through a lit cigarette. Inhaling air conditioner refrigerant gas through a lit cigarette or other smoking method or inhaling fumes released from a flame contacting air conditioner refrigerant gas, can cause bodily harm or death. Do not smoke when servicing air conditioners or wherever refrigerant gas may be present. |
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Damage to the compressor and expansion valve occurs, if the receiver/dryer is not changed when the indicator shows pink or red. |
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Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the machine. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide", for tools and supplies suitable to collect and contain fluids in Caterpillar machines. Dispose of all fluids according to local regulations and mandates. |
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Do not reuse O-ring seals. Replace with Cat® approved replacement O-ring seals. Apply clean lubricant to the new O-ring seals. Ensure that the O-ring seals are seated correctly. Use caution not to damage the O-ring seals during the tightening procedure. |
Required Parts
| Required Parts | ||
| Item | Qty | Part |
| 1 | 1 | 2L-1224 Seal Cap |
| 2 | 1 | 533-0571 Plate(1) |
| 3 | 1 | 257-3226 Refrigerant Dryer As |
| 4 | 1 | 525-4525 Hose As |
| 5 | 2 | 9X-7380 O-Ring Seal |
| 6 | 1 | 533-0551 Hose As |
| 7 | 3 | 9X-7381 O-Ring Seal |
| 8 | 1 | 7K-3176 Refrigerant Coupling Assembly |
| 9 | 3 | 9X-7383 O-Ring Seal |
| 10 | 1 | 2H-3924 Lockwasher |
| 11 | 1 | 7K-3304 Jam Nut |
| 12 | 3 | 9X-7384 O-Ring Seal |
| 13 | 1 | 533-0552 Hose As |
| 14 | 2 | 125-8534 Plate As |
| 15 | 1 | 8T-4136 Bolt |
| 16 | 5 | 8T-4121 Hard Washer |
| 17 | 3 | 132-5789 Clip |
| 18 | 2 | 130-5300 Clip |
| 19 | 2 | 8T-4137 Bolt |
| 20 | 1 | 8T-4196 Bolt |
| 21 | 1 | 344-5675 Nut |
| 22 | 1 | 9X-7378 O-Ring Seal |
| 23 | 13 | 7K-1181 Cable Strap |
| 24 | 1 | 390-0463 Lighting Harness As |
| 25 | 3 | 290-5562 Mount |
| 26 | 2 | 200-6345 Mount |
| 27 | 3 | 3S-2093 Cable Strap |
| 28 | 1 | 5P-3948 Refrigerant Coupling Assembly |
| 29 | 1 | 5P-3950 Cap |
| 30 | 1 | 5P-3951 Plug |
| 31 | 10 ml | 397-7507 Oil |
| (1) | Must be fabricated. Refer to "Procedure to Fabricate the |
Removal Procedure
- Care must be taken during removal of air conditioner lines. Before disconnecting any tube fittings, refer to SENR5664 , Air Conditioning and Heating R134a for all Caterpillar Machines, "Testing and Adjusting".
- Recover the refrigerant from the air conditioning system, refer to , SENR5664, Testing and Adjusting, "Refrigerant Recovery".
Note: During any service of the air conditioning system, all open connections need to be capped or plugged with clean plastic part. Failure to open connections will allow moisture into the system and lead to further damage.
- Remove straps and disconnect hose assembly (A) between condenser and the dryer.
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Illustration 2 g06240321 View looking forward inside engine compartment
(B) Hose Assembly - Remove clips and straps then disconnect hose assembly (B) between conditioner arrangement and the dryer.
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Illustration 3 g06240355 View looking forward inside engine compartment
(C) Clips
(D) Dryer - Loosen clips (C) then remove dryer (D). Retain all hardware for reuse during installation process.
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Illustration 4 g06240630 View of A/C compressor on left side of the engine compartment
(E) A/C pressure switch
(1)2L-1224 Seal Cap - Disconnect A/C pressure switch (E) from the back of the A/C compressor and put one seal cap (1) in place of the A/C pressure switch. Retain pressure switch (E) for reuse later during the installation process.
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Illustration 5 g06240711 View underside of cab support
(F) Remove couplings
(G) Remove plate - Disconnect both refrigerant couplings (F) from plate (G).
Note: The jam nut and lock washer used on plate (G)will be reused during the installation process.
- Remove plate (G) and grind the weld spot clean.
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| Illustration 1 | g06240293 |
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View looking forward inside engine compartment (A) Hose Assembly | |
Procedure to Fabricate the
- Fabricate the 533-0571 Plate using the dimensions above.
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| Illustration 6 | g06254943 |
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(D1) (D2) (D3) (D4) (D5) (D6) (D7) (D8) (D9) (D10) (D11) (D12) 90 degrees (R1) | |
Installation Procedure
Refer to Special Instruction, REHS1841, "General Welding Procedures" prior to performing any welding on the machine.
- Weld plate (2) onto the underside of the cab support frame using the weld dimensions provided.
- Once the areas around welded plate (2) are clean, apply the correct approved Caterpillar paint to protect the metal.
- Use the following general instructions during the rest of the installation procedure:
- Drip clean 397-7507 Oil onto the clean O-ring. Place the O-ring on fittings and ensure that the seal is seated correctly then Oil the O-rings again. Do not reuse the old O-rings
- Do not fold or twist hoses when you are routing the new hoses onto the machine. Damage can occur to the inner layers of the hoses and damage can cause premature failure.
- Tighten the connection with proper torque. Use a wrench to avoid twisting parts. Refer to Specifications, SENR3130, Torque Specifications to find the correct torque value.
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Illustration 8 g06241052 View towards front of machine
(3)257-3226 Refrigerant Dryer As - Mount one refrigerant dryer assembly (3) at the same location as former dryer using the retained clips and hardware that were removed previously.
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Illustration 9 g06241467 View of hose routing
(4)525-4525 Hose As
(5)9X-7380 O-Ring Seal - Connect one hose assembly (4) between the condenser outlet and the dryer inlet along with two O-ring seals (5). Use the existing hardware to secure hose assembly (4) along route.
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Illustration 10 g06241512 View of hose routing
(3)257-3226 Refrigerant Dryer As
(6)533-0551 Hose As
(7)9X-7381 O-Ring Seal
(8)7K-3176 Refrigerant Coupling Assembly
(9)9X-7383 O-Ring Seal - Connect one end of hose assembly (6) to dryer (3) outlet with one O-ring seal (7) and the other end to refrigerant coupling assembly (8) with one O-ring seal (9) and torque to
49 ± 3 N·m (36 ± 2 lb ft) .Show/hide table
Illustration 11 g06241532 View looking up
(2)533-0571 Plate
(A) Existing coupling
(B) Existing jam nut
(C) Existing lock washer - Install existing coupler (A) retained earlier along with jam nut (B) and lock washer (C) into the forward hole in plate (2). Torque to
149 ± 8 N·m (110 ± 6 lb ft) .Show/hide table
Illustration 12 g06241808 View under cab area
(2)533-0571 Plate
(6)533-0551 Hose As
(8)7K-3176 Refrigerant Coupling Assembly
(10)2H-3924 Lockwasher
(11)7K-3304 Jam Nut - Install refrigerant coupling assembly (8) with hose assembly (6) through the remaining hole in plate (2) with one lock washer 10 and one jam nut (11). Torque to
149 ± 8 N·m (110 ± 6 lb ft) .Show/hide table
Illustration 13 g06242122 View of underside of the cab
(A) Refrigerant coupling
(D) Hose from accumulator
(E) Hose from cab air conditioning
(2)533-0571 Plate
(12)9X-7384 O-Ring Seal - Reconnect the existing hoses (D) and (E) to the reinstalled coupling (A) on plate (2) using three O-rings (12). Tighten fittings to
62 ± 3 N·m (45 ± 2 lb ft) .Show/hide table
Illustration 14 g06244849 View of left underside of cab
(8)7K-3176 Refrigerant Coupling Assembly
(9)9X-7383 O-Ring Seal
(13)533-0552 Hose As
(28)5P-3948 Refrigerant Coupling Assembly - Attach hose assembly (13) to refrigerant coupling assembly (28) with O-ring (9). Connect coupling assembly (28) with one more O-ring (9) to coupling assembly (8) Torque fitting to
49 ± 3 N·m (36 ± 2 lb ft) .Show/hide table
Illustration 15 g06242576 View of cab front
(7)9X-7381 O-Ring Seal
(13)533-0552 Hose As
(27)3S-2093 Cable Strap - Route hose assembly (13) up towards the cab air conditioning using the existing hardware and connect to the evaporator inlet with one O-ring seal (7).
- Use two Cable Straps (27) two secure hose (1) to the pre-existing hoses.
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Illustration 16 g06242719 View of front of engine compartment
(14)125-8534 Plate As
(15)8T-4136 Bolt
(16)8T-4121 Hard Washer - Mount two plates (14) to the boss welded on the frame assembly between the dryer and the accumulator using one bolt (15) and one washer (16).
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Illustration 17 g06242816 View of the front plate
(14)125-8534 Plate As
(16)8T-4121 Hard Washer
(17)132-5789 Clip (Ladder)
(18)130-5300 Clip
(19)8T-4137 Bolt - Install two clips (17) and one clip (18) into the end mounting positions on one open end of each plate (14) using two bolts (19) and two hard washers (16).
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Illustration 18 g06243062 View of rear of AC pump unit
(16)8T-4121 Hard Washer
(17)132-5789 Clip (Ladder)
(18)130-5300 Clip
(20)8T-4196 Bolt
(21)344-5675 Nut - Install on the bracket (not shown) for the A/C Compressor using one clip (18), one clip (17), one bolt (20), one nut, (21) and two hard washers (16).
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Illustration 19 g06243088 View of A/C Pressure switch
(4)525-4525 Hose As
(17)132-5789 Clip (Ladder)
(18)130-5300 Clip
(22)9X-7378 O-Ring Seal
(23)7K-1181 Cable Strap - Assemble the A/C pressure switch removed previously to the "schrader" valve on hose assembly (4) installed earlier with one O-ring seal (22). Take the pressure switch harness and connect the receptacle to clip (18) installed previously and secure harness with one cable strap (23) to clip (17). Secure the pigtail to the pressure switch with one cable strap (23).
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Illustration 20 g06243150 View of harness assembly route.
(17)132-5789 Clip (Ladder)
(18)130-5300 Clip
(23)7K-1181 Cable Strap
(24)390-0463 Lighting Harness As
(25)290-5562 Mount - Connect harness assembly (24) plug into the receptacle from the A/C pressure switch and route harness (24) back and down towards the A/ C compressor using nine cable straps (23) and three mounts (25). Refer to above Illustration 20 for harness route. Attach harness (24) receptacle to clip (18) and secure any excess harness to clip (17) using one cable strap (23).
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Illustration 21 g06243374 view of hose assemblies
(6)533-0551 Hose As
(23)7K-1181 Cable Strap
(26)200-6345 Mount
(27)3S-2093 Cable Strap - Secure hose (6) to the existing hose above using one mount (26) and two cable straps (23). Secure the rerouted hose from the cab A/C from earlier using one cable strap (27).
- Evacuate the air conditioning system. Refer to Testing and Adjusting , SENR5664 , Air Conditioning and HeatingRefrigerant System - Evacuate.
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| Illustration 7 | g06240959 |
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(D1) (D2) (W1) (2) | |
