Komatsu 830E-AC Shop Manual page 573

HYDRAULIC BRAKE ACCUMULATORS
There are two hydraulic brake accumulators located
on the brake manifold in the brake control cabinet
behind the operator's cab. Both accumulators are
9.51 l (2.5 gal) capacity. The right one supplies the
pressure necessary for actuation of the front service
brakes. The left accumulator supplies pressure to
activate the rear service brakes.
Accumulators maintain high pressure. DO NOT
disconnect any hydraulic line from the accumula-
tors or brake system until all hydraulic pressure
has been manually drained from accumulators.
Open manual drain valves located on the brake
manifold in the brake cabinet to drain pressur-
ized oil. The manual bleeddown valve for the rear
accumulator is identified as "NV1". The manual
bleeddown valve for the front accumulator is
identified as "NV2".
Brake Accumulator Bleed Down Procedure
The brake accumulators can be bled down by rotat-
ing the manual bleeddown valves (NV1 and NV2)
counterclockwise. The valves are located on the
brake manifold in the hydraulic brake cabinet.
1. Turn manual bleed down handles counterclock-
wise to open valves.
2. Confirm accumulators are bled down by apply-
ing the Brake Lock switch (key switch ON,
engine shut down) and applying service brake
pedal. The service brake light should not come
on.
3. Close bleeddown valves by rotating clockwise.
Removal
1. Shut down engine and exhaust all hydraulic
pressure from the system by opening accumu-
lator manual drain valves.
2. Remove the valve guard and Dyna-seal from
top of accumulators.
3. Depress valve core to release gas precharge
pressure from accumulator bladder. (Refer to
Figure 3-12).
4. Remove accumulator
Loosen and remove accumulator from the
brake manifold. Plug opening on brake manifold
to prevent contamination.
5. Transfer accumulator to work area.
J03034
mounting bracket.
Brake Circuit Component Service
FIGURE 3-12. VALVE CORE REMOVAL
Installation
1. After service repairs or bench test has been
completed, move the accumulators to the brake
control cabinet. DO NOT precharge accumula-
tors on the bench test.
2. Position the accumulators on the brake mani-
fold. Tighten fittings securely. Install mounting
brackets. Secure mounting brackets in place
with cap screws and lockwashers. Tighten cap
screws to standard torque.
3. Refer to Charging Procedure in this section.
4. Replace Dyna-seal and valve guard on top of
accumulators.
Disassembly
1. Securely clamp accumulator (preferably in a
chain vise). Make sure accumulator shell is suit-
ably protected by strips of padding or soft metal
on vise base.
2. Remove core from gas valve using valve core
tool. (Refer to Figure 3-12).
3. Remove pipe plug from plug & poppet.
J3-19