HYDRAULIC SYSTEM RT880E SERVICE MANUAL
2-56 Published 11-10-2014, Control # 524-00
HYDRAULIC ACCUMULATOR SERVICE
BRAKE
Description
The service brake hydraulic accumulators are located on the
outside of the left superstructure side plate behind the cab.
The purpose of each accumulator is to provide stored
energy, an oil volume of 173 cu in (3.0 l) at a maximum
pressure of 2320 psi (15,996 kPa/159.9 bar), to actuate the
service brake circuits. The dual accumulator charge valve
regulates flow to the hydraulic accumulators to provide fully
powered independently separate, primary (front) and
secondary (rear), service brake circuits.
Each accumulator has two chambers divided by a piston.
One side is pre-charged to 1500 psi (10,342 kPa) with high
purity nitrogen. This maintains a constant pressure in the
other chamber which is connected to the modulating brake
valve. After the accumulators are fully charged, they will
provide the necessary brake system flow and pressure to
actuate the brakes.
The accumulator consists of a tube, piston, seals, gas
charging valve, and a gas valve guard.
Maintenance
Removal
1. With the engine shutdown, deplete the hydraulic
pressure in the accumulators by depressing the service
brake pedal several times.
2. Tag and disconnect the hydraulic hose from the
accumulator. Cap or plug the line and port.
3. Remove the two nuts securing each clamp half. Remove
each clamp half and accumulator from the turntable.
Installation
1. Position the accumulator in the clamps and secure with
the removable clamp halves and nuts.
2. Connect the hydraulic hose to the port on the
accumulator as tagged during removal.
3. Pre-charge the accumulator. Refer to Procedure F - Pre-
Charging the Accumulator, page 2-23.
4. Start the engine and check accumulator and hoses for
leaks. Make repairs as needed.
5. Depress the brake pedal several times, make several
turns with the steering wheel, and swing the
superstructure left and right. Verify the brakes, swing,
and front steering work properly.
Servicing
The pre-charge nitrogen pressure should be checked every
200 hours or once a month, whichever comes first. Refer to
Pressure Setting Procedures in this section.
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