vacuum JAGUAR X308 1998 2.G Owner's Guide

Power Brake Actuation - Brake Booster
Description and Operation


The brake b
ooster provides assi
stance by reinforcing the driver's effort when brakin g. The reinforced assistance
provided by the booster is proportional to the driver's effort applied to the brake pedal.
The brake force applied by
the driver is incr
eased by the booster in a ratio of 6.5:1.
Th
e vacuum used to operate the booster
is formed in the engine's intake manifold. The booster is connected to the
intake manifold by a hose.
The boost
er is fail-safe therefore, if a fault develops in
the vacuum unit, the braking system will still function.
However, the driver will have to apply a greater fo rce to the brake pedal to slow down the vehicle.


It e
m
Par
t
Number
De
scr
iption
1—Mas
t
er Cylinder / Reservoir - refer to 206-06
2—Booster

3—Pedal Box
- refer to 206-06
4—Vacuu
m
Hose
5—No
n
-Return Valve

Steering System - Gen
eral Informatio
n - Power Steering System Vacuum
Filling and Bleeding
Gen e
ral Procedures
Fluid Ho

ses



1.

Parts L i
st
It
e
m
De
scr
iption
1R
e
turn hose
2High
pressure h
ose
2. If vacuum filling equipment is available, proceed as follows:
Disconnect both the
high pres
sure hose and return hose
from the PAS pump and the re turn hose from the steering
rack.
D rain as much fl
uid as possible from the system by
turning the steering from lock to lock two or three times.
Re conn
ect all hoses.
Fi
ll
the system using the vacuum equipment according to
the manufacturers instructions.
St art
the engine and top up
the fluid as necessary.
Turn the steering from lock to lock two or three ti mes wi
th
the engine running, topping up with fluid as necessary.
If possibl
e, run the engine for twenty minutes to expel any

remaining air.

(or other sui
table type). Insert the drain / bleed tube
into the fuel
container. Follow the manufa cturer's instructions and
depressurise the fuel system.
5. Store the drained fuel safely and ensure that the lid is closed
securely. Remove the equipmen t and discard the cloth from
beneath the valve. refit the valve cap.

6. Di
sconnect the batt
ery ground cable.
R
emove the battery cover.

7. Disconnect the breather pipe fro m the
A-Bank camshaft cover.
1. Disconnect the breather pipe from the stub pipe.
2. Remove and discard the O-ring seal from the breather
pipe.
8. Disconnect the air fl ow meter multi-plug.
9. Cut and remove the strap which secures the vacuum pipe to
the induction elbow.

10
.
Disconnect the intake tube from the throttle body.
1. Remove the two bolts which secure the intake tube to the throttle body.
2. Disconnect the intake tube from the throttle body.

11. Disconnect the air cleaner cover.
1. Remove the five clips wh ich secure the air cleaner
cover.

12. Remove the intake tube / air flow meter / air cleaner cover
assembly.
1. Remove the intake tube / air flow meter / air cleaner
cover assembly.
2. Remove and discard the ru bber seal; air intake tube
to throttle body.

13. Disconnect the multi-plug s from the throttle body.
1. Disconnect the throttle body motor multi-plug.
2. Disconnect the two potentiometer multi-plugs, one each side of the throttle.
3. Disconnect the vacuum pi pe elbow from the throttle
actuator.

14. Disconnect the throttle inner cable.
Turn the throttle pulley to the fully open position.
Disconnect the throttle in ner cable from the pulley.
15. Disconnect the throttle outer cable.
Remove the throttle cable adjusting nut from the outer
cable.
Remove the cable from the adjustment bracket.

20. Release the induction elbow su pport; working from the right
hand side.
1. Disconnect the vacuum pi pe from the centre of the
induction elbow.
2. Remove the upper bolt from the induction elbow support bracket.

21. Release the induction elbow su pport; working from the left
hand side.
1. Disconnect the vacuum pipe from the front of the
induction elbow.
2. Disconnect the engine breather T-piece from the induction elbow.
3. Remove the upper bolt from the induction elbow support bracket.
4. Loosen, but do not remove , the lower two bolts at the
induction elbow support bracket.

22. Disconnect the electrical conne ctor from each fuel injector.
23. Disconnect the fuel feed hose.
1. Disconnect the fuel f eed hose at the Quick Fit
connector, using special tool 310 - 044.

13. Reconnect the electrical connector to each fuel injector.

14. Refit the induction elbow support ; working from the left hand
side.
1. Fit the upper bolt to the induction elbow support
bracket.
2. Tighten the lower two bolts at the induction elbow support bracket.
3. Connect the engine breather T-piece to the induction elbow.
4. Connect the vacuum pipe to the front of the induction
elbow.

15. Fit the induction elbow support; working from the right hand
side.
1. Fit the upper bolt to the induction elbow support
bracket.
2. Reconnect the vacuum pi pe to the centre of the
induction elbow.
16. Fit the throttle body.
1. Fit a new gasket to the throttle body.
2. Position the throttle body to the induction elbow.

Tighten the locknut without altering the setting or
introducing twist into the cable outer
Check the kickdown setting using the PDU. For scan tool
procedure, refer to 303-14 , Throttle cable, Renew

21. Reconnect the multi-plugs to the throttle body.
1. Connect the throttle body motor multi-plug.
2. Connect the two potentiometer multi-plugs, one each side of the throttle.
3. Connect the vacuum pipe elbow to the throttle
actuator.

22. Fit the intake tube / air flow meter / air cleaner cover
assembly.
1. Fit a new rubber seal; air in take tube to throttle body.

2. Fit the intake tube / air flow meter / air cleaner cover
assembly.

23. Reconnect the air cleaner cover.
1. Fit the five clips which secure the air cleaner cover.
24. Connect the intake tube to the throttle body.
1. Connect the intake tube to the throttle body.
2. Fit the two bolts which secure the intake tube to the throttle body.

25. Reconnect the air flow meter multi-plug.
26. fit a new strap to secures the vacuum pipe to the induction
elbow.

27. Connect the breather pipe to the A-Bank camshaft cover.
1. Fit a new O-ring seal to the breather pipe.
2. Reconnect the breather pipe to the stub pipe.
28. Carefully refit the engine covers, taking care not to damage
the plastic fixings or the rubber inserts.
29. Connect the battery ground cabl e. Refit the battery cover.
Reset the clock and the radio information.
30. Check for leaks and that all pi pes are securely connected.
Remove the protection sheets, close the engine compartment,
luggage compartment and doors.

5. Store the drained fuel safely and ensure that the lid is closed
securely. Remove the equipmen t and discard the cloth from
beneath the valve. refit the valve cap.

6. Disconnect the batt ery ground cable.
Remove the battery cover.

7. Disconnect the breather pipe fro m the A-Bank camshaft cover.
1. Disconnect the breather pipe from the stub pipe.
2. Remove and discard the O-ring seal from the breather
pipe.
8. Disconnect the air fl ow meter multi-plug.
9. Cut and remove the strap which secures the vacuum pipe to
the induction elbow.

10. Disconnect the intake tube from the throttle body.
1. Remove the two bolts which secure the intake tube to the throttle body.
2. Disconnect the intake tube from the throttle body.

11. Disconnect the air cleaner cover.
1. Remove the five clips wh ich secure the air cleaner
cover.

12. Remove the intake tube / air flow meter / air cleaner cover
assembly.
1. Remove the intake tube / air flow meter / air cleaner
cover assembly.
2. Remove and discard the ru bber seal; air intake tube
to throttle body.

13. Disconnect the multi-plug s from the throttle body.
1. Disconnect the throttle body motor multi-plug.
2. Disconnect the two potentiometer multi-plugs, one each side of the throttle.
3. Disconnect the vacuum pi pe elbow from the throttle
actuator.

14. Disconnect the throttle inner cable.
Turn the throttle pulley to the fully open position.
Disconnect the throttle in ner cable from the pulley.
15. Disconnect the throttle outer cable.
Remove the throttle cable adjusting nut from the outer
cable.
Remove the cable from the adjustment bracket.