R1700 Load Haul Dump Power Train, Steering, Braking, Hydraulic, and Machine Systems Caterpillar

Ride Control Accumulator - Test and Charge

Usage:

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Personal injury or death can result if two persons are not used in the following procedure.

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Personal injury can result from hydraulic oil pressure and hot oil.
Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system.

Make sure all of the work tools have been lowered to the ground, and the oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.

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Dry nitrogen is the only gas approved for use in the accumulators. The charging of oxygen gas in an accumulator will cause an explosion. An explosion can be eliminated by using nitrogen gas cylinders with standard CGA (Compressed Gas Association, Inc.) No. 580 connectors. When nitrogen gas is ordered, make sure to order the cylinders with CGA No. 580 connectors.

Do not rely on color codes or other methods of identification to tell the difference between nitrogen and oxygen cylinders. In any application, never use an adapter to connect your nitrogen charging group to a valve outlet used on both nitrogen, oxygen, or other gas cylinders. BE SURE YOU USE DRY NITROGEN (99.8% purity).

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NOTICE

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, PERJ1017, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat^® products. Dispose of all fluids according to local regulations and mandates.

Specifications

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Table 1
Accumulator Pre Charge Pressure/Temperature Relationship for a Typical Accumulator with a Pre Charge of 4000 kPa (580 psi)
Temperature	Pressure⁽¹⁾
−5° C (23° F)	3800 kPa (550 psi)
0° C (32° F)	3835 kPa (556 psi)
5° C (41° F)	3875 kPa (562 psi)
10° C (50° F)	3915 kPa (568 psi)
15° C (59° F)	3955 kPa (574 psi)
20° C (68° F)	3990 kPa (580 psi)
25° C (77° F)	4030 kPa (585 psi)
30° C (86° F)	4070 kPa (590 psi)
35° C (95° F)	4110 kPa (595 psi)
40° C (104° F)	4150 kPa (600 psi)
45° C (113° F)	4185 kPa (610 psi)

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⁽¹⁾	Nominal allowable tolerance equals 215 kPa (32 psi).

Note: The pressures in Table 1 are recommended for machines with a typical bucket. Machines with heavier buckets may require an increase in nitrogen pressure to keep the accumulator piston from striking the stop during normal roading. Raising the nitrogen pressure will result in a stiffer ride.

Introduction

The following procedure provides information on discharging and charging the ride control accumulator.

Required Tools

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Table 2
Required Tools
Tool	Item	Qty	Part No	Description
D		-	175-5507	Nitrogen Charging Group
D	D1	1	8S-4600	Fitting
	D2	1	8S-1506	Coupling As
	D3	1	162-4147	Hose As
	D4	1	8S-4599	Coupling As
	D5	1	2S-5244	Fitting
	D6	1	1S-8937	Fitting
	D7	1	8T-0859	Pressure Gauge
	D8	1	162-4146	Regulator
	D9	1	7S-5106	Chuck
	D10	1	1S-8938	Chuck
	D11	1	1S-8941	Hose As

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Illustration 1	g01624351

Charging Preparation

Shutdown Procedure

Move the machine to a hard level surface away from operating machines and away from personnel.
Place the transmission direction and speed control in the NEUTRAL position and in any speed position.
Engage the parking brake. Place wheel blocks in front of the wheels and behind the wheels.
Stop the engine.
Install the steering frame lock. Refer to Operation and Maintenance Manual, "Steering Frame Lock".
Start the engine. Keep the engine running above 1500 rpm during Step 7 through Step 9.
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Illustration 2 g06133797

Location of the ride control switch
(A) Left indicator
(B) Right indicator
Push and hold the button to enable the service mode function of the ride control.
Lower the bucket to the ground.
Move the joystick control lever to the FLOAT position to release hydraulic pressure in the ride control accumulator.
Reference: For more information about releasing the hydraulic pressure in the system, refer to Systems Operation, Testing and Adjusting, "System Pressure - Release".
Decrease engine speed to low idle.
Stop the engine.
Turn the key start switch to the OFF position.

Discharging the Accumulator

Reference: For more information about discharging the accumulator refer to Special Instruction, REHS5464, "Accumulator Discharging and Charging Procedures."

If the accumulator must be replaced, first perform "Shutdown Procedure". Then, perform the following Steps:

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Illustration 3	g06245787
Location of the ride control accumulator

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Illustration 4	g06133801
Ride control accumulator (1) Nitrogen charging valve (2) Guard

Remove guard (2) which protects nitrogen charging valve (1).
Remove the protective cap on nitrogen charging valve (1).
Install Tooling (D6), Tooling (D7), Tooling (D10) , and Tooling (D11) to nitrogen charging valve (1).
Note: Ensure Tooling (D6) is closed, and the valve handle on Tooling (D10) is turned all the way in the counterclockwise direction.
Place the open end of Tooling (D11) away from the work area and away from personnel.
Move the valve handle on Tooling (D10) all the way in the clockwise direction.
Open Tooling (D6) to release all the nitrogen from the accumulator.

Charging Procedure

New or Rebuilt Accumulator

If a new or rebuilt accumulator is not being installed, proceed to "Nitrogen Charging".

Prior to installing a new or rebuilt ride control accumulator, remove all the air from the nitrogen chamber of the accumulator. Fill the accumulator with approximately 1.9 L (2.01 qt) of SAE 10W hydraulic oil in the nitrogen end of the accumulator. The oil is used to remove air out of the nitrogen chamber and also to lubricate the top seal of the accumulator piston.

Discharge the ride control accumulator.
Reference: For more information about discharging the accumulator refer to Special Instruction, REHS5464, "Accumulator Discharging and Charging Procedures."
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Illustration 5 g06133802
Remove nitrogen charging valve (1).
With the accumulator in the vertical position put approximately 1.9 L (2.01 qt) of SAE 10W hydraulic oil in the nitrogen end of the accumulator.
Move the accumulator piston fully to the nitrogen charging valve end of the accumulator. As the accumulator piston moves to the nitrogen charging valve end of the accumulator, the air and then the oil will be pushed out. When the flow of oil stops, the accumulator will be free of air and the top seal of the accumulator piston will be lubricated.
Install nitrogen charging valve (1).
Install the ride control accumulator. Refer to Disassembly and Assembly - Machine Systems, "Ride Control Accumulator - Remove and Install".
Charge the ride control accumulator, refer to "Nitrogen Charging".

Nitrogen Charging

First perform "Charging Preparation".

With the engine running above 1500 rpm, push and hold the ride control switch to enable the service mode , and Tooling (D6) open, perform the following steps:

Raise the lift arms to the maximum height and hold the joystick control lever in the RAISE position for 5 seconds. The piston will move all the way to the charge valve end of the ride control accumulator to charge the accumulator.
Close Tooling (D6).
Lower the bucket to the ground. Move the joystick control lever to the FLOAT position.
Install the remainder of Tooling (D) and connect to a nitrogen cylinder.
Adjust Tooling (D8) to set the appropriate charge pressure on the pressure gauge. Refer to Table 1
Note: To ensure that the accumulator nitrogen charge valve is correct, the accumulator piston must be at the accumulator charge valve end of the accumulator cylinder. Nitrogen pressure varies with the temperature. To obtain the most accurate nitrogen charge, the temperature of the accumulator should equal the outside air temperature. However, the temperature of the accumulator could be higher than the outside air temperature sometimes. If so, the temperature of the accumulator should be used instead of the outside air temperature.
Open Tooling (D6). The nitrogen pressure should show on Tooling (D7) within 20 seconds.
If the nitrogen pressure shows on Tooling (D7) in less than 10 seconds, repeat Step 1 through Step 6.
If the ride control accumulator is properly charged, move the valve handle on Tooling (D10) all the way in the counterclockwise direction.
Close Tooling (D6).
Push and hold the ride control button. The ride control switch will return to the OFF position.
Stop the engine.
Release the pressure in Tooling (D) prior to removing Tooling (D).
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Illustration 6 g06133801

Ride control accumulator
(1) Nitrogen charging valve
(2) Guard
Install the protective cap on nitrogen charging valve (1) and guard (2).

Adjustment Procedure - Road Test

Note: The pressures in Table 1 are recommended for machines with a typical bucket. For machines with a heavy bucket, the nitrogen pressure may require increasing. The accumulator piston will be prevented from striking the stop during normal roading while the ride control system is activated. Raising the nitrogen pressure will result in a stiffer ride.

Put a typical load in the bucket.
Press and hold the ride control button to the SERVICE position.
Drive the machine over a rough road surface.
If machine bounces or accumulator piston strikes the stop, increase the nitrogen Precharge pressure by 345 kPa (50 psi) and perform another road test.
Note: Only add enough nitrogen to achieve a suitable ride for the machines typical payload.