Range Rover Classic
ABS
1
FAULT DIAGNOSIS
ACCUMULATOR PRECHARGE
Check
The diaphragm type accumulator is precharged with
nitrogen at 80 bar, its function is to store hydraulic
energy. Over a period of several years a normal loss
of precharge will occur. This procedure will indicate
extent to which precharge pressure has fallen.
NOTE: A new accumulator at 20
°
C has a
nominal pressure of 80 bar + 2. Minimum
acceptable pressure is 50 bar.
Equipment - LRT-70-001 ABS pressure test
equipment
1. Depressurise brake system.
See Repair,
Depressurise System
2. Remove banjo bolt securing high pressure hose,
use a second spanner on large hexagon to
prevent it being slackened.
3. Fit pressure gauge adapter, using sealing
washers. Connect pressure gauge.
4. Switch ignition on and observe pressure gauge.
5. There should be a rapid rise in pressure to
accumulator precharge, point X, of 80 bar, then
a slowing down in rate of increase as pressure
rises to system pressure, 180 bar, see graph A
6. Accumulator has lost precharge if point x occurs
below 80 bar, see graph B
7. Fit new accumulator if point X occurs below 50
bar.
8. Depressurise system, remove pressure gauge
and adapter.
9. Fit banjo bolt securing high pressure hose, use
NEW sealing washers. Tighten to
15 Nm.
10. Bleed pump.
11. Check/top up fluid level.
