Dodge ram truck 3500 1996 Service Manual page 226

CLEAHiNG AND I N S P E C T I O N fContinued)
' Fig. 90 Shoe Contact Surfaces
Replace the piston i f cracked or scored. Do not
attempt to restore a scored piston surface by sanding
or polishing. The piston must be replaced i f damaged.
NOTE: If the caliper piston must be replaced,
install the same type of piston in the caliper. Newer
interchange phenolic resin and steel caliper pis­
tons. The pistons, seals, seal grooves, caliper bore
and piston tolerances are different for resin and
steel pistons. Do not intermix these components at
any time.
The bore can be lightly polished with a brake hone
to remove very minor surface imperfections (Fig. 91).
The caliper should be replaced i f the bore is severely
corroded, rusted, scored, or i f polishing would
increase bore diameter more than 0.025 mm (0.001
inch).
SPECIAL HONE CALIPER
Fig. 91 Lightiy Polishing Piston Bore With Tool
WHEEL C Y L i l i E R
CLEANING
Clean the cylinder and pistons with clean brake
fluid or brake cleaner only. Do not use any other
cleaning agents.
Dry the cylinder and pistons with compressed air.
Do not use rags or shop towels to dry the cylinder
components. Lint from cloth material will adhere to
the cylinder bores and pistons.
INSPECTION
Inspect the cylinder bore. Light discoloration and
dark stains In the bore are normal and will not
impair cylinder operation.
;
The cylinder bore can be lightly polished but only
with crocus cloth. Replace the cylinder i f the bore is
scored, pitted or heavily corroded. Honing the bore to
restore the surface is not recommended.
Inspect the cylinder pistons. The piston surfaces
should be smooth and free of scratches, scoring and
corrosion. Replace the pistons i f worn, scored, or cor­
roded. Do attempt to restore the surface by sanding
or polishing.
Discard the old piston cups and the spring and
expander. These parts are not reusable. The original
dust boots may be reused but only If they are in good
condition.
A D J U S T M E N T S
STOP LAMP SWITCH
(1) Push and hold brake pedal down
(2) Pull switch plunger all the way out to fully
extended position.
(3) Push switch plunger Inward 4 detent positions
(or clicks). This is required preset position. Plunger
will extend approximately 14 mm (0.55 in.) out of
housing at this setting.
(4) Release brake pedal. Then lightly pull pedal
fully rearward. Pedal will adjust switch plunger to
correct position as pedal is moved to rear.
CAUTION: Do not use excessive force to move the
pedal rearward for switch adjustment. Excessive
force will damage t h e switch.
REAR DRUM BRAKE
The rear drum brakes are equipped with a self-ad­
justing mechanism. Under normal circumstances, the
only time adjustment is required is when the shoes
are replaced, removed for access to other parts, or
when one or both drums are replaced.
Adjustment can be made with a standard brake
gauge or with adjusting tool. Adjustment is per-