Mercedes-Benz 300 SD 1978 Owner's Manual page 43

Safe D riving
instrum ent cluster com es on, either
the brake fluid level in the reservoir is
too low or the brake system is leaking.
Brake pad wear may cause a shortage
of brake fluid in the reservoir. Install
only brake pads recom m ended by us.
I , If other than recom m ended brake
9 m , pads are installed, the braking
pro perties of the vehicle can be
affected to an extent that the safety is
substantially im paired.
Brake Pad Wear Indicator
The brake pad wear in d ica tor in the
instrum ent cluster com es on when the
key in the steering lock is turned to
driving position " 2" and itm u s tg o o u t
when the engine is running. If the
in dica tor lights up during braking or
driving, this shows that the fro n t wheel
brake pads are w orn down.
Have brake system checked in a
MERCEDES-BENZ service station as
soon as possible.
42
Brake Fluid
During the course of the operation of
the vehicle, the boiling point of the
brake flu id is continuously being
reduced through the absorption of
m oisture from the atm osphere. Under
extrem ely hard operating conditions,
this m oisture content can lead to the
fo rm ation of vap o r in the system thus
reducing the system 's efficiency. The
brake fluid m ust th erefore be
replaced annually, preferably in the
spring. It is recom m ended to use only
b ra k e flu id approved by MERCEDES-
BENZ. Your MERCEDES-BENZ
dealer will provide you with additional
inform ation.
Charge Indicator Light
Should the charge indicator light fail
to com e on p rio r to starting when the
ignition key is in position "2 " or should
it fail to go out after starting or during
operation, this indicates a fault which
m ust be repaired at a MERCEDES-
BENZ service station as soon as
possible.
Oil Pressure Gauge
The oil pressure may d rop at idle
speed to 7.1 psi (0.5 kp /sq .cm ) if the
engine is at operating tem perature.
This will not je opardize its operational
reliability. Pressure must, however,
rise im m ediately upon acceleration.
Coolant Temperature Gauge
Due to the pressurized cooling
system, the coolant only starts boiling
at a tem perature of approx. 257° F
(125° C) with an antifreeze-blended
coolant fill protecting down to -22° F
(-30° C) (see also " Fuels, Coolants,
Lubricants, etc." ).
The coolant tem perature may rise to
the red m arking in the case of high
am bient tem peratures and when
travelling in m ountainous terrain.