Chrysler 1998 Voyager Service Manual page 99

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DIAGNOSIS AND TESTING (Continued)
(4) Remove the 2 bolts (Fig. 19) attaching the pro-
portioning valve to the frame rail.
CAUTION: When lowering the proportioning valve,
care must be taken not to kink any of the chassis
brake lines.
(5) Carefully lower the proportioning valve for
clearance to install the proportioning valve test fit-
tings.
(6) Install the required fitting from Pressure Test
Fittings, Special Tool 6833 (Fig. 20) into the inlet
port of the proportioning valve assembly, from which
the chassis brake line was removed. Install the
removed chassis brake line into the Pressure Test
Fitting (Fig. 20). Install the required fitting from
Pressure Test Fittings, Special Tool 6833 into the
required outlet port of the proportioning valve.
Install the required fitting from Pressure Test Fit-
tings, Special Tool 6833 into the required outlet port
of the proportioning valve (Fig. 20). Then install the
removed chassis brake line into the Pressure Test
Fitting (Fig. 20).
Fig. 20 Proportioning Valve Test Fitting Installation
(7) Install a pressure gauge from Gauge Set, Spe-
cial Tool C-4007-A into each pressure test fitting (Fig.
21). Bleed air out of hose from pressure test fittings
to pressure gauges, at the pressure gauges (Fig. 21).
Then bleed air out of the brake line being tested, at
that rear wheel cylinder.
(8) With the aid of a helper, apply pressure to the
brake pedal until a pressure of 6895 kPa (1000 psi) is
obtained on the proportioning valve inlet gauge.
Then based on the type of brake system the vehicle is
equipped with and the pressure specification shown
on the following table, compare the pressure reading
on the outlet gauge to the specification. If outlet
pressure at the proportioning valve is not within
specification when
obtained, replace the proportioning valve.
required inlet pressure
Fig. 21 Pressure Gauges Installed On Pressure Test
(9) Repeat steps 2 through 7 for the other propor-
tioning valve of the assembly.
CAUTION: When
replacement proportion valve on the frame rail of
the vehicle install the mounting bolts in only the
two forward holes of the mounting bracket (Fig. 19).
HEIGHT SENSING PROPORTIONING VALVE
CAUTION: The use of after-market load leveling or
load capacity increasing devices on this vehicle are
prohibited. Using air shock absorbers or helper
springs on this vehicle will cause the height sens-
ing proportioning valve to inappropriately reduce
the hydraulic pressure to the rear brakes. This inap-
propriate reduction in hydraulic pressure potentially
could result in increased stopping distance of the
vehicle.
When a premature rear wheel skid is obtained on a
brake application, it may be an indication that the
hydraulic pressure to the rear brakes is above the
specified output from the proportioning valve. This
condition indicates a possible malfunction of the
height sensing proportioning valve, which will
require testing to verify that it is properly controlling
the hydraulic pressure allowed to the rear brakes.
Premature rear wheel skid may also be caused by an
incorrectly adjusted proportioning valve actuator
assembly, or contaminated front or rear brake lin-
ings.
Prior to testing a proportioning valve for function,
check that all tire pressures are correct. Also, ensure
the front and rear brake linings are in satisfactory
condition. It is also necessary to verify that the
brakes shoe assemblies on a vehicle being
is
tested, are either original equipment manufac-
turers (OEM), or original replacement brake
BRAKES
Fittings
mounting the original
5 - 17
or a