Lotus 2004 ELISE Service Notes page 233

Lotus Service Notes
Operational Check
As a quick check of servo operation proceed as follows: With the engine stopped, press the brake pedal
several times to exhaust the servo unit of vacuum. Keeping the pedal pressed (which should be 'hard' and
'high'), start the engine; The pedal should drop slightly as the servo vacuum builds up, and extra force is
produced. If the pedal does not drop, it is most likely that there is a fault in the vacuum supply line. Check the
vacuum hose, all connections and the non-return valve. If the vacuum supply is not defective, the servo unit
should be replaced.
Setting brake pedal: It is essential that the servo piston (and master cylinder piston) is allowed to return fully
when the brakes are released, and is not pre-loaded by mal-adjustment of the input pushrod. See sub-section
JJ.11.
Stop light switch: The stop switch is mounted in a right angle bracket fixed to the underside of the scuttle, and
abuts directly against the pedal. The switch is retained in the bracket by a quarter turn mechanism.
To Replace Brake Servo Unit
1. Remove the brake master cylinder (see sub-section JJ.9).
2. From within the footwell, disconnect the servo pushrod from the brake pedal.
3. Disconnect the brake servo vacuum hose, and release the four nuts securing the servo to the pedal box
extension plinth. Withdraw the servo assembly.
4. Replace the servo in reverse order to the above, tightening the servo mounting nuts to 25 Nm, and the
new master cylinder fixing nuts to 25 Nm. Check pushrod adjustment (see sub-section JJ.11) and bleed
the hydraulic system.
Pedal box
Page 18
Servo mounting bracket
to pedal box fixing
j191
Section JJ
Brake servo
Servo to mounting
bracket fixing nut