AP-1055B and BG-2455C Asphalt Pavers Auxiliary System Caterpillar

Note: The following procedures must be performed in order. If the procedures are not completed in order, the procedures will not work properly. If necessary, the Purging and Charging the Hydraulic Pressure is the only procedure that may be performed without completing the earlier procedures.

Check for the Hydraulic Pressure In the Accumulator

Table 1

Required Tools
Tool	Part Number	Part Description	Quantity
A	148-1886	Female Coupler	1
B	8T-0859	Pressure Gauge	1

1. Install a 148-1886 Female Coupler to a 8T-0859 Pressure Gauge.
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   Illustration 1	g00639450

2. Attach the coupler to purge port (1) that is on the ram.

   Note: Machines that have the older style of track tension cylinder may have both a hose and a port for purging. The port is attached to the top of the cylinder.

3. Rotate the gauge to open the high-pressure quick coupler.

4. Read the pressure. The pressure should be 16550 ± 345 kPa (2400 ± 50 psi). If the pressure is low, you need to check the nitrogen pressure of the accumulator.

Releasing Track Tension Oil Pressure

1. Shut off the engine.
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   Illustration 2	g00639451

2. Loosen the bolts and slide the guard that covers the track tension manifold to gain access to needle valve (2) and male test port (3).

3. Connect the supply hose for the track tension to male test port (3).

4. Locate needle valve (2). Rotate counterclockwise one turn to open the valve.

5. Turn the engine start switch to the ON position. Do not start the engine.
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   Illustration 3	g00639452

6. Move tow point control (4) up and down and repeat several times, allowing the pressurized oil to go directly to the hydraulic tank. Observe the belt to verify that the tension is released.

7. Locate needle valve (2). Rotate clockwise one turn to close the valve, preventing the tension cylinder from pressurizing.

8. The pressure is now released from the track tension system.

Checking and Charging the Nitrogen Pressure

Note: Before you check the nitrogen pressure, perform the above procedure to release the pressure for the track tension.

Note: Refer to the temperature-pressure chart to find the correct accumulator precharge pressure that corresponds to the ambient air temperature.

Table 2

Temperature-Pressure Chart for the Accumulator Precharge Pressure
Temperature	Pressure for 107-6328 Accumulator	Pressure for 130-7623 Accumulator
48.9 °C (120 °F)	11321 kPa (1642 psi)	15093 kPa (2189 psi)
43.3 °C (110 °F)	11121 kPa (1613 psi)	14824 kPa (2150 psi)
37.8 °C (100 °F)	10928 kPa (1585 psi)	14569 kPa (2113 psi)
32.2 °C (90 °F)	10728 kPa (1556 psi)	14307 kPa (2075 psi)
26.7 °C (80 °F)	10535 kPa (1528 psi)	14052 kPa (2038 psi)
21.1 °C (70 °F)	10342 kPa (1500 psi)	13790 kPa (2000 psi)
15.5 °C (60 °F)	10149 kPa (1472 psi)	13528 kPa (1962 psi)
10 °C (50 °F)	9949 kPa (1443 psi)	13272 kPa (1925 psi)
4.5 °C (40 °F)	9756 kPa (1415 psi)	13010 kPa (1887 psi)
−1.1 °C (30 °F)	9563 kPa (1387 psi)	12748 kPa (1849 psi)
−6.7 °C (20 °F)	9363 kPa (1358 psi)	12486 kPa (1811 psi)
−12.2 °C (10 °F)	9170 kPa (1330 psi)	12224 kPa (1773 psi)
−17.8 °C (0 °F)	8977 kPa (1302 psi)	11969 kPa (1736 psi)
−23.3 °C (−10 °F)	8777 kPa (1273 psi)	11707 kPa (1698 psi)
−29 °C (−20 °F)	8584 kPa (1245 psi)	11445 kPa (1660 psi)
−34.5 °C (−30 °F)	8391 kPa (1217 psi)	11190 kPa (1623 psi)
−40 °C (−40 °F)	8198 kPa (1189 psi)	10928 kPa (1585 psi)

Procedure for the 107-6328 Accumulator

Illustration 4	g00585691

Table 3

Required Tools
Tool	Part Number	Part Description	Quantity
C	1U-5551	Valve Extension	1
D	224-5152	Male-to-Male Adapter(1)	1
E	222-2367	Male-to-Female Adapter(2)	1
F	7S-8712	Pressure Gauge	1
G	7S-5437	Nitrogen Charging Group	1

(1)	For use with Female Fittings
(2)	For use with a Male and a Female Fitting

Note: The left track tension manifold is identical to the right track tension manifold. The right track tension manifold is located below the pump compartment and the manifold is mounted on the mainframe. The left track tension manifold is located below the radiator compartment and the manifold is on the mainframe.

1. Turn the engine start switch to the OFF position.

2. Use the following steps to check the nitrogen charge pressure in the accumulator.

   1. Remove the metal plug at the rear of the accumulator.

   2. Install a 1U-5551 Valve Extension to the end of the 107-6328 Accumulator.

   3. Install a 224-5152 Adapter OR a 222-2367 Adapter to the valve extension.

   4. Install a 7S-8712 Pressure Gauge to the adapter to check the pressure. The pressure should be 10340 ± 1520 kPa (1500 ± 220 psi).

      Note: Refer to the temperature-pressure chart to find the correct accumulator precharge pressure that corresponds to the ambient air temperature.

   5. If the accumulator pressure is low, check the accumulator for leakage at end covers.

   6. If leakage is found, replace the accumulator.

   7. If no leak is found or the accumulator was replaced, recharge the accumulator with 7S-5437 Nitrogen Charging Group. Recharge to a pressure of 10340 ± 1520 kPa (1500 ± 220 psi).

      Note: Refer to the temperature-pressure chart to find the correct accumulator precharge pressure that corresponds to the ambient air temperature.

   8. Remove the adapter, the gauge, and the valve extension. Install the metal plug at the rear of the accumulator.

      Note: When the nitrogen pressure has been checked and serviced properly, you will need to perform the procedure for Purging and Charging the Hydraulic Pressure.

Procedure for the 130-7623 Accumulator

Illustration 5	g00640269

Table 4

Required Tools
Tool	Part Number	Part Description	Quantity
G	9U-6740	Nitrogen Charging Group	1
H	1U-7565	Wrench (6 mm Hex)	1
I	151-8856	Seal (Charging)	1

1. Remove the cover over the plug and make sure that the area does not have any paint or grease on the area. Be sure that the side of the gauge for purging is closed.

2. Rotate the plug counterclockwise by 60° with a 1U-7565 Wrench.

   Note: Do not loosen the plug more than 60°, or pressure may be lost.

3. Connect 9U-6740 Nitrogen Charging Group and 151-8856 Seal (Charging) to charging group into the plug on 130-7623 Accumulator.

4. Hold the tee while you thread the charging group onto the accumulator to ensure that the tee does not turn.

   Note: Make sure that the charging group is tight.

5. Loosen the plug counterclockwise by 1 to 2 turns.

   Note: Do not turn the plug more than two turns.

6. The gauge should read 15170 ± 1515 kPa (2200 ± 220 psi).

   Note: If the accumulator is not at the proper pressure, service the accumulator with 9U-6740 Nitrogen Charging Group and 151-8856 Seal (Charging). Use the instructions in the charging group to service the accumulator to a pressure of 15170 ± 1515 kPa (2200 ± 220 psi). Reference the temperature-pressure chart to find the correct pressure that corresponds to the ambient air temperature.

7. Hand tighten the plug clockwise with the tee on the assembly. Relieve the pressure on the gauge by turning the purge valve counterclockwise. Remove the charging group from the accumulator. Tighten the plug to a maximum torque of 11.5 N·m (8.5 lb ft).

   Note: When the nitrogen pressure has been checked and serviced properly, you will need to perform the procedure for Purging and Charging the Hydraulic Pressure.

Purging and Charging the Hydraulic Pressure

Table 5

Required Tools
Tool	Part Number	Part Description	Quantity
J	8T-0859	Pressure Gauge	1
K	122-6887	Hose (50 inches)	1
	124-2111	Permanent Coupling	1
	148-1886	Female Coupler	1
	4J-5477	O-Ring Seal	1
	8C-6866	Connector	1

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Illustration 6	g00639451

1. Connect the oil supply hose in the auxiliary system to the track tension manifold.

2. Open needle valve (2) on top of the manifold 1 to 2 turns.

   Note: Use the following parts to assemble the purge line: 122-6887 Hose (50 inches), 124-2111 Permanent Coupling, 148-1886 Female Coupler, 4J-5477 O-Ring Seal, and 8C-6866 Connector.

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   Illustration 7	g00639450

3. Connect the purge line to purge port (1) that is on the ram. Leave the nut on the female end of the purge line in the off position. Place the other end of the hose into a bucket to capture the oil while you purge the system.

   Note: Machines that have the older style of track tension cylinder may have both a hose and port for purging. The hose or port is attached to the top of the cylinder.

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   Illustration 8	g00639453

4. Connect a 8T-0859 Pressure Gauge to test port (5) on the hopper and grade/slope valve.

5. Remain clear of the track and start the engine. The ram will quickly move the front idler in the forward direction to put tension on the track.

6. Adjust the auxiliary pump pressure compensator to raise the pressure to 16550 kPa (2400 psi).

7. Open the female quick disconnect fitting by holding the quick disconnect fitting and turning the purge line. Allow the oil to be purged from the track tension system. The mixture will appear white and the mixture will have foam. The air that is discharging can be felt passing through the hose.

   1. Shut quick disconnect fitting on the purge line.

   2. Turn off the engine.

   3. Turn the engine start switch to the ON position. Do not start the engine.
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      Illustration 9	g00639452

   4. Move tow point control (4) up and down and repeat several times, allowing the pressurized oil to go directly to the hydraulic tank.

8. Repeat Step 5 through Step 7 three or four times to ensure that the system is purged.

9. When all the air has passed from the ram, start the engine and properly charge the system to 16550 kPa (2400 psi).

10. Shut off the needle valve for the oil supply at the manifold.

    Note: The maximum torque that should be applied to the needle valve is 13.5 N·m (10 lb ft). Torquing the needle valve over the maximum torque may result in breakage of the needle valve.

11. Shut off the engine. Allow the auxiliary system pressure on the gauge in test port (5) of the hopper and grade/slope valve to drop to zero. Disconnect the purge line from the manifold. Disconnect the supply hose at the manifold and replace the dust caps and covers on the quick disconnect fittings.

12. Slide the guard that covers the track tension manifold and tighten the cover bolts.

13. Start the engine and reset the auxiliary pump pressure back to 14475 kPa (2100 psi). 14475 kPa (2100 psi) is the normal operating pressure of the auxiliary system.