Mercedes-Benz 300 SD 1978, Owner'S Manual

Page: 42 / 79

Safe Driving
The retention of the specified tire
pressure is essential. This applies
pa rticu la rly if the tires are subjected to
high loads (e. g. high speeds, heavy
loads, high am bient tem peratures).
Aquaplaning:
Depending on the depth of the w ater
layer on the road, aquaplaning may
occur even with tire s still show ing the
full tread depth, and even at low
speeds. Avoid track grooves in the
road and apply brakes cautiously in
the rain.
Tire frictio n :
Dry road = 100 %
Wet road = fro m approx. 50 % to
approx. 80 % (be p a rticu la rly cautious
on wet and d irty roads)
Icy road = approx. 15 %
You should pay p a rticu la r attention to
the condition of the road as soon as
the prevailing te m p e ra tu re s fall close
to the freezing point. If ice has fo rm e d
on the road (e. g. due to fog), a thin
film of w ater is then q u ickly p roduced
on the ice w hich su b sta n tia lly reduces
the g rip of the tires. U nder such
w eather co n d ition s, drive, steer and
brake p a rtic u la rly carefully.
We recom m end M +S ra d ia l-p ly tires
fo r the cold season. On ice or p a ck­
ed snow, they can reduce y o u r s to p p ­
ing distance as co m p a re d with su m ­
m er tires. S to p p in g distance,
however, is nevertheless c o n s id e r­
ably gre a te r than when the road is wet
or dry.
On extended and steep declines,
relieve brakes by sh iftin g the selector
lever to position “ S” or “ L” .
A fter hard b raking it is advisable not
to switch o ff the engine rig h t away but
to drive on fo r som e tim e so the air
stream w ill cool down the brakes
faster.
When d rivin g in heavy rain fo r som e
tim e w ith o u t applying the brakes, the
firs t braking action may be som ew hat
retarded and increased pedal
pressure may be necessary. For this
reason, s ta y fu rth e r away from vehicle
in front.
Once in a w hile check the effective­
ness of the system by fully applying
the brakes on an open road (m ake
sure the wheels will not lock). This will
also im p ro ve the g rip of the linings.
The co n d itio n of the p arking brake
w ill be checked durin g every m ain­
tenance service. F urtherm ore it is
recom m e n d e d to exert once or tw ice
between the re g u la r m aintenance
services, a m axim um pressure of
22 lbs. (10 kp) on the p arking brake
pedal fo r 10 seconds while travelling
at a speed aro u n d 30 mph (50 k m /h )
on dry road. Pull release knob during
this process! Repeat p rocedure
once or twice. Exercise care, the
sto p lig hts do not w ork.
Have all in sp e ction s of and w ork on
the bra ke system carried out by a
MERCEDES-BENZ service station.
If the p arking bra ke is released and
the brake w arning light in the