Chrysler neon 1997 Service Manual page 84

PROPORTIONING MASTER CYLINDER PROPOR- TIONINGVALVES SECONDARY VALVES BRAKE TUBE
PL
DESCRIPTION AND OPERATION (Continued)
Fig. 14 Non-ABS Master Cylinder Primary And
Secondary Ports
(Fig. 15) supplies hydraulic pressure to the left front
and right rear brakes.
Fig. 15 ABS Master Cylinder Primary And
Secondary Ports
VACUUM BOOSTER
All vehicles use a 230 mm single diaphragm power
brake vacuum booster. There are however two differ-
ent booster designs; one for vehicles equipped with
ABS and one for vehicles without ABS. These two
boosters differ at the interface to the master cylinder.
If the power brake booster requires replacement be
sure it is replaced with the correct part.
The power brake booster can be identified by the
tag attached to the body of the booster assembly (Fig.
16). This tag contains the following information: The
production part number of the power booster assem-
bly, the date it was built, who manufactured it, and
brake sales code.
NOTE: The power brake booster assembly is not a
repairable part and must be replaced as a complete
PRIMARY BRAKE TUBE MASTER MASTER CYLINDER PRI- ONDARY OUTPUT PORTS MARY OUTPUT PORTS CYLINDER MASTER BRAKES ANTILOCK CYLINDER H.C.U. SEC- MASTER CYLINDER MOUNT- MASTER CYLINDER PUSH VACUUM CHECK VALVE ING STUDS ROD
unit if it is found to be faulty in any way. The power
booster vacuum check valve is not repairable but
can be replaced as an assembly.
Fig. 16 Power Brake Booster Identification
The power brake booster reduces the amount of
force required by the driver to obtain the necessary
hydraulic pressure to stop vehicle.
The power brake booster is vacuum operated. The
vacuum is supplied from the intake manifold on the
engine through the power brake booster check valve
(Fig. 16).
As the brake pedal is depressed, the power booster
input rod moves forward (Fig. 17). This opens and
closes valves in the power booster, allowing atmo-
spheric pressure to enter on one side of a diaphragm.
Engine vacuum is always present on the other side.
This difference in pressure forces the output rod of
the power booster (Fig. 17) out against the primary
piston of the master cylinder. As the pistons in the
master cylinder move forward this creates the
hydraulic pressure in the brake system.
Different engine options available for this vehicle
require that different vacuum hose routings be used.
The power brake vacuum booster assembly mounts
on the engine side of the dash panel. It is connected
to the brake pedal by the input push rod (Fig. 17). A
vacuum line connects the power booster to the intake
manifold. The master cylinder is bolted to the front
of the power brake vacuum booster assembly.
RED BRAKE WARNING LAMP
The red Brake warning lamp is located in the
instrument panel cluster and is used to indicate a
low brake fluid condition or that the parking brake is
applied. In addition, the brake warning lamp is
turned on as a bulb check by the ignition switch
when the ignition switch is placed in the crank posi-
tion. Problems with this system will generally be of
the type where the warning lamp fails to turn on
when it should, or remains on when it should not.
PART BOOSTER BRAKE POWER IDENTIFICA- TION TAG ASSEMBLY
BRAKES 5 - 7