669 / 1575
BRAKES
15
BRAKES
WORKING PRINCIPLE :
The Thermoclip is assembled between the
adjuster nut and the adjuster push rod.
In the brake 'OFF' condition, the shoe return
spring forces the shoe webs against the adjuster
rods.
When brakes are applied the shoes move
outward and there will be no force on the adjuster
rods. Also the shoe movement makes the pawl to
rotate the adjuster nut ensuring adjustment.
Around 150 deg. C, the thermo clip opens and
the force exerted by the thermoclip will become
higher than the force exerted by adjuster pawl at
the hinge point. At this condition, the adjuster rods
are moved outward and also the rotation of the
nut is prevented. Thus the clearance which is
caused due to thermal expansion does not result
in over adjustment.
BRAKE MAINTENANCE
Note : The rear brake shoes have to be replaced
insets only. If you are replacing brake shoes on
left side brakes then the brake shoes on right side
brakes should also be replaced.
To maintain the efficiency of the brake system,
preventive maintenance is essential and the
following recommendations should be observed at
the intervals stated.
BRAKE ADJUSTMENT
As it is an auto adjust brakes, brake adjustment is
not required.
1. Every 10,000 kms check the lining for wear
through the inspection hole provided in the
back plate, removing the grommet (35). The
linings should not be allowed to wear down to
rivet heads.
2. Every 20,000 kms clean the back plate and
lubricate the tips of the shoe platforms with
graphite grease and the moving parts of the
adjuster with mineral grease. Keep the grease
away from the shoe lining sand all hydraulic
parts.
3. The wheel cylinder should be overhauled once
in 40,000 kms or 18 months whichever is
earlier.
MAJOR OVERHAUL
It is essential that the shoe linings are inspected
at regular intervals to prevent the drums being
permanently damaged and subsequently making
drum removal extremely difficult. If the drums are
allowed to become scored or grooved, the
problem of drum removal can usually be
overcome by increasing the clearance between
the shoe linings and drum as follows :
Caution :
As it is an auto brake, press the hand
brake lever with a screw driver inserted through
the hole from rear side of the back plate.