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Recoil system contains high-pressure nitrogen cylinder. Parts can separate with explosive force if proper care is not used during disassembly. This action can cause serious injury or death. Do not disassemble any part of this cylinder until you have read and understand the instructions given in the service manual. Observe the instructions given in the service manual. |
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Operating the machine with low pressure in the Nitrogen accumulator for the recoil system may cause damage to the machine. Replace any accumulator that will not maintain nitrogen pressure. |
- Remove the track adjust cover. See illustration 5 and illustration 6.
Note: Loss of Nitrogen (N2) charge in the recoil system may cause additional loosening of the track. This pressure may be retained inside the track roller frame. Take caution when removing the track adjust cover.
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Illustration 1 g03329767 Earlier models: TAN1-436, ; TJA1-444 Show/hide table
Illustration 2 g03329012 Later models: TAN437-Up, ; TJA445-Up - Measure dimension (Y). See Illustrations 1 and 2. Dimension (Y) should be between
15 mm (0.6 inch) and40 mm (1.6 inch) . If dimension (Y) is less than15 mm (0.6 inch) , check to ensure that the accumulator is assembled into the track roller frame correctly. Refer to the Disassembly & Assembly Manual, KENR5606, "Track Adjuster and Recoil Cylinder - Remove and Install" - If dimension (Y) is greater than
40 mm (1.6 inch) , continue to Step 4 to check the recoil cylinder for the correct charge level. If dimension (Y) is between15 mm (0.6 inch) and40 mm (1.6 inch) , then proceed to Step 9.Note: Do not operate the machine with improper Nitrogen accumulator pressure. This action may damage the machine.
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Illustration 3 g03338060 Show/hide table
Illustration 4 g03337974 Left track adjuster and recoil group - Loosen bottom twelve-point head bolt (B). Remove top twelve-point head bolt (A) and rotate protector cover (C) that is on the outside of track adjusting mechanism (4).
- Check the precharge pressure in recoil cylinder (3) for your ambient temperature range at valve (5). The N2 precharge pressure should be within
± 345 kPa (50 psi) of the pressure that is listed in Table 1. The operating range can be shifted by adjusting the precharge pressure for a given temperature.Note: Use only the proper nitrogen charging equipment to adjust the accumulator precharge pressure.
Reference: See Testing and Adjusting, KENR5604, "Accumulator (Track Tension) - Test and Charge" for additional information.
The recoil cylinder operates with nitrogen gas pressure. The following table shows the nitrogen precharge pressures for different ambient operating temperatures.
Show/hide tableTable 1 Ambient Temperature N2 Precharge Pressures −34 °C (−30 °F) 14373 kPa (2085 psi) −29 °C (−20 °F) 14708 kPa (2133 psi) −23 °C (−10 °F) 15042 kPa (2182 psi) −18 °C (0 °F) 15377 kPa (2230 psi) −12 °C (10 °F) 15712 kPa (2279 psi) −7 °C (20 °F) 16047 kPa (2327 psi) −1 °C (30 °F) 16381 kPa (2375 psi) 4 °C (40 °F) 16716 kPa (2425 psi) 10 °C (50 °F) 17051 kPa (2473 psi) 16 °C (60 °F) 17385 kPa (2521 psi) 21 °C (70 °F) (1)17720 kPa (2570 psi) (2)27 °C (80 °F) 18055 kPa (2619 psi) 32 °C (90 °F) 18390 kPa (2667 psi) 38 °C (100 °F) 18724 kPa (2715 psi) 43 °C (110 °F) 19059 kPa (2764 psi) 49 °C (120 °F) 19394 kPa (2813 psi) 52 °C (125 °F) 19561 kPa (2837 psi) Show/hide table(1) 21 °C (70 °F) is the nominal temperature. By this example,15377 kPa (2230 psi) at−18 °C (0 °F) temperature is the equivalent pressure of the nominal pressure at the nominal temperature.(2) 17720 kPa (2570 psi) is the nominal pressure at the nominal temperature of21 °C (70 °F) . - After the accumulator pressure has been corrected, allow the Nitrogen cylinder to stand for 10 minutes in order to stabilize. Recheck the pressure in order to confirm pressure.
- Replace protector cover (C).
- Repeat the procedure for the recoil cylinder on the other track roller frame.
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Personal injury or death can result from grease under pressure.
Grease coming out of the relief valve under pressure can penetrate the body causing injury or death.
Do not watch the relief valve to see if grease is escaping. Watch the track or track adjustment cylinder to see if the track is being loosened.
Loosen the relief valve one turn only.
If track does not loosen, close the relief valve and contact your Caterpillar dealer.
- Prior to performing any track adjustment, make sure that the Nitrogen cylinder is properly charged.
- Move the machine forward for a distance of two times the length of the machine, if required. Slowly reduce the machine to zero speed with the travel control pedal. Shut off the engine. Adjust the tracks while you are in the machine typical operating conditions. If packing conditions prevail on the job, the tracks should be adjusted with packing material.
Note: Perform Steps 11 through 15 on both sides of the machine.
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Illustration 5 g01873340 D7E
Left track roller frameShow/hide table
Illustration 6 g01874393 D7E LGP
Right track roller frame - Remove the recoil system access cover, if needed.
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Illustration 7 g01871293 Top view of left track roller frame Show/hide table
Illustration 8 g02348777 Side view of right track roller frame - Add grease through track adjustment valve (1) in order to tighten the track. To loosen the track, rotate relief valve (2) counterclockwise. Then close the relief valve .
Note: If no relief valve is present, rotate track adjustment (fill) valve (1) counterclockwise to loosen the track.
- Set the front track sag to the following dimensions in Table 2.
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Table 2 D7E Track Sag (Range) Location D7E D7E LGP Front (A) 35 mm (1.4 inch) to45 mm (1.8 inch) 25 mm (1.0 inch) to30 mm (1.2 inch) Center (B) 15 mm (0.6 inch) to20 mm (0.8 inch) 25 mm (1.0 inch) to35 mm (1.4 inch) Total (A + B) 50 mm (2.0 inch) to65 mm (2.6 inch) 50 mm (2.0 inch) to65 mm (2.6 inch) - Since the track adjuster manifold can move during track adjustment, perform Steps 2 and 3 .
- Replace the recoil system access cover.
