SMART Series 451 Service Manual page 73

SN_Typ 451_us.book Seite 72 Freitag, 30. November 2007 1:56 13
Brakes
Pedals
The seals and the boot on the pedals may not be
damaged otherwise moisture can penetrate into the
interior compartment.
To ensure that the pedals remain leaktight, the brake
pedal module cover must be replaced each time the
pedals are disassembled.
Brake light switch
The brake light switch in the pedal assembly is only
accessible after the brake pedal module cover has
been removed.
The brake light switch is actuated via the linkage in
the pedal assembly when the brake is actuated. The
signal from the brake light switch is read by the ESP
control unit.
The free travel of the brake light switch must be
correctly adjusted to ensure that the brake light
switch operates properly.
Brake lines
All brake lines may only be retightened twice at the
most when work is performed on the vehicle. If a
threaded connection on a brake line is loosened and
then retightened, this must be documented. The
respective threaded connection must be marked in
color with a suitable safety paint.
The following color codings are specified:
• First retightening: yellow marking
• Second retightening: red marking
If the respective threaded connection is loosened
again after being retightened for a second time, the
detached brake line must be replaced. This also
applies if it is not possible to trace how often the
threaded connection has previously been loosened.
72 Introduction of the smart fortwo, Model Series 451
Brake system bleeding
Whereas the brake fluid can be replaced by one
person, the hydraulic brake system can only be bled
by two people working together. When bleeding the
primary and secondary circuit, one person must build
up the pressure required by the brake fluid changer
by repeatedly actuating the brake pedal. The second
person is needed to:
• Actuate the ESP hydraulic unit via diagnosis at the
same time and perform the bleeding procedure
when bleeding the primary circuit
• Perform the bleeding procedure when bleeding the
secondary circuit
i Note
To ensure that the brake system is not damaged,
the filling pressure on the brake fluid changer
may be set to max. 2.8 psi (2 bar).
Basic adjustment of brake shoes
After brake shoes are replaced or removed/installed,
basic adjustment of the drum brake must be
performed. To do so, the brake shoes are measured
and adjusted using the slack adjuster.
Drum brake adjustment
Manual adjustment of the clearance between brake
shoe and brake drum is not permissible. Adjustment
may only be performed via the automatic slack
adjuster of the brake shoes to prevent grinding or
locking of the drum brake.
i Note
See the Workshop Information System (WIS) for the
exact procedure for repairing the brake system
and for the relevant safety information.