Operation and maintenance manual

Section 250-0060
Braking System - Accumulator
SM 2160 7-02
4
SM - 278
REMOVAL
Numbers in parentheses refer to Fig. 3, unless
otherwise specified.
WARNINGS
To prevent personal injury and property
damage, be sure wheel blocks, blocking
materials and lifting equipment are properly
secured and of adequate capacity to do the job
safely.
Accumulators are charged with Nitrogen.
The service pressure is 55 bar (800 lbf/in²) at
21° C (70
o
F). To prevent personal injury and
property damage do not attempt to remove any
valves or fittings until all nitrogen pressure is
completely relieved.
1. Position the vehicle in a level work area, apply the
parking brake, switch off the engine and turn steering
wheel in both directions several times to relieve any
pressure in the steering circuit.
2. Operate the treadle valve continuously to relieve
pressure in the braking system. Block all road wheels
and place battery master switch in the 'Off' position.
3. Remove screws (2, Fig. 1), lockwashers (3, Fig. 1)
and protector (4, Fig. 1).
4. Discharge nitrogen from the accumulators as
described under 'Discharging Nitrogen'.
5. Disconnect hydraulic lines from underside of
accumulators and drain oil into a suitable container.
Cap open lines and fittings to prevent entry of dirt.
6. Support accumulators with an adequate sling and
lifting device. Remove bolts (1 & 2), washers (3) and
clamps (4). Remove accumulators to a clean area for
disassembly.
DISASSEMBLY
Numbers in parentheses refer to Fig. 1.
WARNING
Accumulators are charged with Nitrogen. The
service pressure is 55 bar (800 lbf/in²) at 21° C
(70
o
F). To prevent personal injury and
property damage do not attempt to remove any
valves or fittings until all nitrogen pressure is
completely relieved.
1. Make sure all nitrogen gas has been released
before starting to disassemble the accumulator. Refer
to section on 'Discharging Nitrogen'.
2. Remove charging valve (1) from end cap (10).
3. With accumulator lying horizontal, hold accumulator
cylinder (12) with a strap wrench.
4. Install pins in three equally spaced holes in end cap
(10), then use a long bar working against the pins to
remove end cap from cylinder (12). Remove and
discard 'O' ring (9).
5. Grip cast web of piston (5) with pliers and, while
rotating, pull piston from cylinder (12). Remove and
discard wear rings (8), backup rings (6) and 'V' section
ring (7).
INSPECTION
Numbers in parentheses refer to Fig. 1.
1. Wash metal components with a suitable solvent and
thoroughly air dry.
2. Inspect piston (5) for cracks or burrs. Replace
piston (5) if excessively scored or worn.
Fig. 3 - Accumulator Installation
1- Bolt
2- Bolt
3- Washer
4- Clamp
5 - Accumulator