Broderson RT-400-A, Operation And Maintenance Manual

Page: 63 / 93

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Brake Accumulators: Mounted under the floorboard of the operator’s compartment. The brake
accumulators store hydraulic oil under pressure for use at the brake calipers. They are bladder-
type accumulators, and require a pre-charge pressure in the gas bladder. The brake accumula-
tor pre-charge pressure must be maintained on a monthly basis as follows:
1. Set park brake or put machine on outriggers. Turn off engine.
2. Pump the brake pedal several times to discharge stored oil pressure.
3. Remove protective cap from the accumulator.
4. Connect a pressure gauge to the accumulator valve stem.
W A R N I N G
Accumulator pressure gauges will not detect accumulator pre-charge pressure if im-
properly used. Carefully review pressure gauge and pre-charging instructions included
with commercially available gauge kits.
5. Measure accumulator gas pre-charge pressure. Nominal pressure is 1000 ± 100 PSI (69 ± 6.8
bar).
W A R N I N G
NEVER use shop air or oxygen to pre-charge accumulators. ONLY use inert dry nitrogen
(N
2
) gas. Failure to use proper gas can cause accumulator damage or failure, leading to
property damage, injury, or death.
6. If necessary, add only dry nitrogen gas (N
2
).
7. Disconnect all gauges. Replace valve caps.
If the accumulators are unable to hold a pre-charge pressure, or if the brakes fail to operate
properly, they may be damaged. The accumulator pressures should cycle between 2175 PSI
(150 bar) and 2675 PSI (184 bar). Accumulator bladder replacement instructions and accumu-
lator replacement instructions ship with replacement parts. In the event that instructions are not
included, contact BMC. Proper procedure is necessary to prevent damage or premature failure
of replacement parts.