Chrysler 1998 Voyager Service Manual page 87

NS
DESCRIPTION AND OPERATION (Continued)
The caliper is a one piece casting with the inboard
side containing a single piston cylinder bore.
The phenolic piston is 60 mm (2.36 inch) in diam-
eter.
A square cut rubber piston seal is located in a
machined groove in the cylinder bore. It provides a
hydraulic seal between the piston and the cylinder
wall (Fig. 4).
The molded rubber dust boot mounts in a counter
bore of the cylinder bore opening and in a groove
which is machined in the outer surface of the piston
(Fig. 4). This prevents contamination of the piston
and the bore area.
Fig. 4 Caliper Piston Seal Function For Automatic
Adjustment
As lining wears, reservoir level will go down. If
fluid has been added, reservoir overflow may occur
when the piston is pushed back into the new lining
position. Overflowing can be avoided by removing a
small amount of fluid from the master cylinder res-
ervoir.
REAR DRUM BRAKES
The rear wheel drum brakes are a two shoe, inter-
nal expanding type with an automatic adjuster screw.
The automatic adjuster screw is actuated each time
the brakes are applied. The automatic adjuster screw
is located directly below the wheel cylinder.
REAR DISC BRAKES
The rear disc brakes are similar to front disc
brakes, however, there are several distinctive fea-
tures that require different service procedures. The
single piston, floating caliper rear disc brake system
includes a hub and bearing assembly, adapter, rotor,
caliper, and brake shoes. The parking brake system
on vehicles equipped with rear disc brakes, consists
of a small duo-servo drum brake mounted to the cal-
iper adapter. The drum brake shoes expand out
against a braking surface (hat section) on the inside
area of the rotor.
This vehicle is equipped with a caliper having a 42
mm (1.65 in.) piston and uses a 15 inch solid non-
vented rotor.
The disc brake caliper floats on rubber bushings
using threaded guide pin bolts which are attached to
the back side of the adapter.
The adapter and rotor shield are mounted to the
rear axle. The adapter is used to mount the brake
shoes and actuating cables for the parking brake sys-
tem. The adapter is also used to mount the rear cal-
iper. The adapter has two machined abutments
which are used to position and align the caliper and
brake shoes for movement inboard and outboard (Fig.
5).
Fig. 5 Rear Disc Brake Components
PARKING BRAKE SYSTEM OPERATION
The rear wheel service brakes also act as parking
brakes. The brake shoes are mechanically operated
by an internal lever and strut connected to a flexible
steel cable. The rear cables and intermediate cable
are connected to the front cable by an equalizer. The
front cable extends to the parking brake foot pedal
assembly.
PROPORTIONING VALVES
FIXED PROPORTIONING VALVE
The hydraulic brake system on all vehicles is diag-
onally split. This means that the left front and right
rear brakes are on one hydraulic circuit with the
right front and left rear brakes on the other hydrau-
lic circuit.
On vehicles equipped with ABS brakes, the brake
systems hydraulic control unit (HCU) is mounted to
the front suspension crossmember on the driver's
side of the vehicle. The (HCU) acts as the hydraulic
system junction block, diagonally splitting the brakes
hydraulic system.
All vehicles equipped with ABS brakes use 2 fixed
proportioning valves. The fixed proportioning valves
are mounted in a common bracket on the left frame
rail at the rear of the vehicle (Fig. 6).
BRAKES 5 - 5