PLATE 2200588 - Caterpillar

Table 2
Ambient Temperature versus Charging Pressure for the 415-8304 Hydraulic Accumulator Gp (High pressure)
Ambient Temperature Charging Pressure(1)
−18° C (0° F) 10496 kPa (1522 psi)
−12° C (10° F) 10743 kPa (1558 psi)
−7° C (20° F) 10949 kPa (1588 psi)
−1° C (30° F) 11195 kPa (1623 psi)
4° C (40° F) 11401 kPa (1653 psi)
10° C (50° F) 11648 kPa (1689 psi)
16° C (60° F) 11895 kPa (1725 psi)
21° C (70° F) 12000 kPa (1740)
27° C (80° F) 12348 kPa (1790 psi)
32° C (90° F) 12554 kPa (1820 psi)
38° C (100° F) 12801 kPa (1856 psi)
43° C (110° F) 13007 kPa (1886 psi)
49° C (120° F) 13253 kPa (1922 psi)
54° C (130° F) 13459 kPa (1952 psi)
60° C (140° F) 13706 kPa (1987 psi)
(1) 345 kPa ( 50 psi)Introduction
The cushion-hitch accumulators allow the tractor to be cushioned from sudden shock movement of the scraper.Machine Preparation
Move the machine to a smooth, horizontal location. Move the machine away from other operating machines and away from personnel. Place the transmission direction control switch in the NEUTRAL position. Engage the parking brake. Lower the work bowl to the ground. Stop the engine and put chocks in front of the wheels and behind the wheels.Turn off the engine. Make sure that the engine has not been operating for at least 5 minutes. This time period is long enough to allow the hydraulic oil to flow out of the bottom chamber of the accumulator. The piston in the accumulator must be on the bottom of the cylinder to charge the accumulator correctly.The precharge pressure of the 415-8308 Hydraulic Accumulator Gp (Low pressure) is 5000 kPa (725 psi) at a temperature of 21°C (70° F). The precharge pressure of the 415-8304 Hydraulic Accumulator Gp (High pressure) is 12000 kPa (1740) at a temperature of 21° C (70°F).The air temperature outside the accumulator is the ambient temperature. Before the dry nitrogen pressure in the accumulator may be accurately checked, the temperature of the accumulator must be equal to the ambient temperature. Before the accumulator may be correctly charged, the temperature of the accumulator must be equal to the ambient temperature.Use Table 1 to determine the correct charging pressure for the 415-8308 Hydraulic Accumulator Gp (Low pressure) at a given ambient temperature.Use Table 2 to determine the correct charging pressure for the 415-8304 Hydraulic Accumulator Gp (High pressure) at a given ambient temperature.
Illustration 1 g03721042
(A) Low-pressure accumulator
(B) High-pressure accumulatorChecking the Dry Nitrogen Pressure in the Cushion-Hitch Accumulator
Refer to Special Instruction, REHS5464, "Accumulator Discharging and Charging Procedures" to check the dry nitrogen pressure of the cushion-hitch accumulator.Charging the Cushion-Hitch Accumulator
Increase the nitrogen pressure in the accumulator according to the following steps:
Refer to Special Instruction, REHS5464, "Accumulator Discharging and Charging Procedures" to charge the cushion-hitch accumulator.Charging a Rebuilt Cushion-Hitch Accumulator
When the accumulator has been rebuilt, the air must be removed from the upper chamber of the accumulator. When the accumulator has been