Dodge Dakota 2001, Service Manual

Page: 173 / 2307

In summary, fluid pressure acting simultaneously
on both piston and caliper, produces a strong clamp-
ing action. When sufficient force is applied, friction
will attempt to stop the rotors from turning and
bring the vehicle to a stop.
Application and release of the brake pedal gener-
ates only a very slight movement of the caliper and
piston. Upon release of the pedal, the caliper and pis-
ton return to a rest position. The brake shoes do not
retract an appreciable distance from the rotor. In
fact, clearance is usually at, or close to zero. The rea-
sons for this are to keep road debris from getting
between the rotor and lining and in wiping the rotor
surface clear each revolution.
The caliper piston seal controls the amount of pis-
ton extension needed to compensate for normal lining
wear.
During brake application, the seal is deflected out-
ward by fluid pressure and piston movement (Fig. 7).
When the brakes (and fluid pressure) are released,
the seal relaxes and retracts the piston.
The amount of piston retraction is determined by
the amount of seal deflection. Generally the amount
is just enough to maintain contact between the pis-
ton and inboard brake shoe.
BRAKE LINES
DESCRIPTION
Flexible rubber hose is used at both front brakes
and at the rear axle junction block. Double walled
steel tubing is used to connect the master cylinder to
the major hydraulic braking components and then to
the flexible rubber hoses. Double inverted style and
ISO style flares are used on the brake lines.
OPERATION
The hoses and lines transmit the brake fluid
hydraulic pressure to the calipers and or wheel cyl-
inders.
DIAGNOSIS AND TESTING - BRAKE LINE AND
HOSES
Flexible rubber hose is used at both front brakes
and at the rear axle junction block. Inspect the hoses
whenever the brake system is serviced, at every
engine oil change, or whenever the vehicle is in for
service.
Inspect the hoses for surface cracking, scuffing, or
worn spots. Replace any brake hose immediately if
the fabric casing of the hose is exposed due to cracks
or abrasions.
Also check brake hose installation. Faulty installa-
tion can result in kinked, twisted hoses, or contact
with the wheels and tires or other chassis compo-
nents. All of these conditions can lead to scuffing,
cracking and eventual failure.
The steel brake lines should be inspected periodi-
cally for evidence of corrosion, twists, kinks, leaks, or
other damage. Heavily corroded lines will eventually
rust through causing leaks. In any case, corroded or
damaged brake lines should be replaced.
Factory replacement brake lines and hoses are rec-
ommended to ensure quality, correct length and supe-
rior fatigue life. Care should be taken to make sure
that brake line and hose mating surfaces are clean
and free from nicks and burrs. Also remember that
right and left brake hoses are not interchangeable.
Use new copper seal washers at all caliper connec-
tions. Be sure brake line connections are properly
made (not cross threaded) and tightened to recom-
mended torque.
BRAKE PADS/SHOES
REMOVAL
(1) Clean master cylinder reservoir and filler caps.
(2) Remove reservoir filler cap and drain approxi-
mately 1/4 of fluid from reservoir. Use clean suction
gun or similar device to drain fluid.
(3) Raise and support vehicle.
(4) Remove front wheel and tire assemblies.
(5) Bottom caliper pistons in bores with large
C-clamp. Position clamp frame on rear of caliper and
clamp screw on outboard brake shoe.
(6) With a screw driver pry up on the caliper
spring and pull the spring out of the caliper holes.
(7) Remove caliper slide pins.
(8) Remove caliper, (Refer to 5 - BRAKES/HY-
DRAULIC/MECHANICAL/DISC BRAKE CALIPERS
- REMOVAL) and brake shoes (Fig. 8).
Fig. 7 Lining Wear Compensation By Piston Seal
1 - PISTON
2 - CYLINDER BORE
3 - PISTON SEAL BRAKE PRESSURE OFF
4 - CALIPER HOUSING
5 - DUST BOOT
6 - PISTON SEAL BRAKE PRESSURE ON
5 - 10 BRAKES - BASE
AN
HYDRAULIC/MECHANICAL (Continued)