BLOCK 1240065 - Caterpillar

Do not use an adapter to connect the nitrogen charging equipment to a valve that can be used on oxygen cylinders or gas cylinders. Use dry nitrogen.
Illustration 1 g02988296Two bladder type steering accumulators (1) were installed on machines FDB1-1216. The accumulators are located on the right side of the machine in front of the suspension cylinder. The bladder type steering accumulator has a dry charge of 6550 350 kPa (950 50 psi).Use the following information to check the nitrogen pre-charge pressure in the steering accumulators, to discharge, and to charge the steering accumulators.Nitrogen gas pressure varies with the temperature. To obtain the most accurate nitrogen charge, the temperature of the accumulator must be identical to the air temperature around the accumulator.Note: Adjust the pressure for ambient conditions, as required. Refer to the following table for the accumulator pre-charge pressure/temperature relationship.
Table 2
Relationship Between the Charging Pressure and the Ambient Temperature for Piston Type Accumulator
Ambient Temperature Charging Pressure(1)
−7°C (20°F) 6005 kPa (870 psi)
−1°C (30°F) 6060 kPa (880 psi)
4°C (40°F) 6170 kPa (895 psi)
10°C (50°F) 6280 kPa (910 psi)
16°C (60°F) 6390 kPa (927 psi)
21°C (70°F) 6500 kPa (942 psi)
27°C (80°F) 6610 kPa (959 psi)
32°C (90°F) 6720 kPa (975 psi)
38°C (100°F) 6830 kPa (990 psi)
43°C (110°F) 6940 kPa (1007 psi)
49°C (120°F) 6995 kPa (1015 psi)
(1) The allowable tolerance on nominal pressure is 70 kPa (10 psi).Do not use an adapter to connect the nitrogen charging equipment to a valve that can be used on oxygen cylinders or gas cylinders. Use dry nitrogen.Check that the engine has not been running for at least 5 minutes to allow the oil level in the steering accumulators to decrease. This will ensure that the pressure of the nitrogen charge is correct.The steering accumulator has a dry charge of 6550 350 kPa (950 50 psi).
Illustration 2 g02988343Three piston type steering accumulators (2) were installed on machines FDB1217-Up. The accumulators are located on the right side of the machine in front of the suspension cylinder. The piston type steering accumulator has a dry charge of 6550 331 kPa (950 48 psi).Start by performing the following steps.
Permit only one operator on the machine. Either keep other personnel away from the machine, or keep other personnel in the sight of the operator.
Move the machine to a smooth horizontal location. Move the machine away from any machines that are working and any personnel.
Move the transmission control to the PARK position.
Activate the parking brakes. Stop the engine.Note: When you move the engine start switch to the OFF position, a solenoid valve is activated. The solenoid valve releases the hydraulic steering pressure from the steering accumulators. Relieving the pressure in the steering circuit will not release the nitrogen precharge pressure in the steering accumulators.
Place blocks in front of the wheels and behind the wheels.
Check that the engine has not been running for at least five minutes. The time will allow the oil level in the steering accumulators to decrease.