Release the vacuum from insid the servounit by depressing the brake pedal severaltimes.
although not absolutely necessary,to inprove access to the sensor,remove the master cylinder fluid reservoir as described in section 13.
disconnect the battery negative terminal,then disconnect the wiring connector from the pedal position sensor.
using a small screwdriver,carefully lever off the sensor retaining clip,then withdraw the sensor from the front of the vacuum servounit.recover the sealing ring and circlip.
refitting
if a new senseor is being fitted,note the colour of the spacer fittrd to the original sensor,and fit the relevant colour spacer to the new sensor. this is vital to ensure that the correct operation of the anti-lock braking system.
fit the new circlip to the groove on the front of the vacuum servo unit, positioning its end gap over the servo unit sensor locating slot.
fit the new sealing ring to the sensor,lubricating it with a smear of oil to aid installation.
fit the sensor to the vacuum servo,aligning its locating notch with the servo unit upper groove. push the sensor until it clicks into position, and check that it is securely retained by the circlip.
reconnect the sensor wiring,and connect the battery negative terminal.