Chrysler PT Cruiser. Manual — part 426
REMOVAL
REMOVAL - LHD
NOTE: Before proceeding, (Refer to 5 - BRAKES -
WARNING) (Refer to 5 - BRAKES - CAUTION).
(1) Disconnect negative (ground) cable from the
battery and isolate the cable.
(2) Remove the master cylinder. (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL/MASTER
CYLINDER - REMOVAL)
(3) If the vehicle is equipped with ABS, remove the
integrated control unit (ICU). (Refer to 5 - BRAKES/
HYDRAULIC/MECHANICAL/ICU
(INTEGRATED
CONTROL UNIT) - REMOVAL)
(4) Disconnect the vacuum hoses from the check
valve on the power brake booster (Fig. 109), but do
not remove the check valve from power brake
booster.
(5) Inside the vehicle, remove the silencer pad
below the knee blocker.
(6) Fold down and remove the knee blocker.
(7) Locate the brake pedal-to-power brake booster
input rod attachment under the instrument panel.
Position a small screwdriver under the center tang of
the retaining clip (Fig. 110). Rotate the screwdriver
enough to allow the retaining clip tang to pass over
the end of the brake pedal pin. Remove the clip.
CAUTION: Discard the used retaining clip, it is not
to be reused. Replace the clip with a new one on
reassembly.
(8) Remove the four nuts attaching the power
brake booster to the instrument panel (Fig. 111). The
nuts are accessible from under the instrument panel
in the area of the brake pedal bracket.
(9) Slide the power brake booster forward until
mounting studs clear the instrument panel, then
remove it from the vehicle.
REMOVAL - RHD
NOTE: Before proceeding, (Refer to 5 - BRAKES -
WARNING) (Refer to 5 - BRAKES - CAUTION).
(1) Disconnect negative (ground) cable from the
battery and isolate the cable.
(2) Using a R-134a refrigerant recovery machine,
remove the refrigerant from the A/C system. (Refer to
Fig. 109 Vacuum Check Valve
1 - VACUUM CHECK VALVE
Fig. 110 Retaining Clip
1 - BRAKE PEDAL
2 - INPUT ROD
3 - SCREWDRIVER
4 - RETAINING CLIP
5 - BRAKE PEDAL PIN
Fig. 111 Power Brake Booster Mounting
1 - CLIP
2 - BOOSTER MOUNTING NUTS
3 - BOOSTER MOUNTING NUTS
5 - 56
BRAKES - BASE
PT
POWER BRAKE BOOSTER (Continued)
24 - HEATING & AIR CONDITIONING - STAN-
DARD PROCEDURE)
(3) Disconnect the refrigerant lines at their mid-
line connection block just above the upper engine
torque strut. Position the refrigerant lines out of the
way and cap all openings to prevent contamination.
(4) Remove the master cylinder. (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL/MASTER
CYLINDER - REMOVAL)
(5) Inside the vehicle, remove the silencer pad
below the knee blocker.
(6) Fold down and remove the knee blocker.
(7) Locate the brake pedal-to-power brake booster
input rod attachment under the instrument panel.
Position a small screwdriver under the center tang of
the retaining clip (Fig. 110), then rotate the screw-
driver enough to allow the retaining clip tang to pass
over the end of the brake pedal pin. Remove the clip.
CAUTION: Discard the used retaining clip, it is not
to be reused. Replace the clip with a new one on
reassembly.
(8) Remove the four nuts attaching the power
brake booster to the instrument panel. The nuts are
accessible from under the instrument panel in the
area of the brake pedal bracket.
(9) Slide the power brake booster forward until
mounting studs clear the dash panel, then remove it
from engine compartment by carefully positioning
booster lip past edge of engine cover. Use care to pre-
vent breaking valve cover.
INSTALLATION
INSTALLATION - LHD
NOTE: Before power brake booster installation, be
certain dash seal is installed on booster mounting
studs.
(1) Install the power brake booster by sliding the
input rod and studs through the dash panel and into
mounting position.
(2) Under the instrument panel, install the four
power brake booster mounting nuts (Fig. 111).
Tighten the nuts to a torque of 34 N·m (25 ft. lbs.).
(3) Using Mopar
t Lubriplate, or an equivalent,
coat the surface of the brake pedal pin where it con-
tacts the brake booster input rod.
CAUTION: Use only a new brake booster input rod-
to-brake pedal retaining clip to ensure proper
retainment.
(4) Connect the power brake booster input rod-to-
brake pedal pin. Install a new retaining clip. Do not
use the old clip.
CAUTION: Do not reuse the original brake lamp
switch. The switch can only be adjusted once. That
is during initial installation of the switch. If the
switch
is
not
adjusted
properly
or
has
been
removed for some service, a new switch must be
installed and adjusted.
(5) Remove and replace the brake lamp switch
with a NEW switch. Discard the original brake lamp
switch. (Refer to 8 - ELECTRICAL/LAMPS/LIGHT-
ING
-
EXTERIOR/BRAKE
LAMP
SWITCH
-
REMOVAL) (Refer to 8 - ELECTRICAL/LAMPS/
LIGHTING - EXTERIOR/BRAKE LAMP SWITCH -
INSTALLATION)
(6) Install the knee blocker.
(7) Install the silencer pad below the knee blocker.
CAUTION: When installing the vacuum hoses onto
the check valve, make sure the hoses are routed
properly to avoid possible contact with the exhaust
manifold and other unfriendly surfaces.
(8) Connect all previously removed vacuum hoses
to the vacuum check valve (Fig. 109).
(9) If the vehicle is equipped with ABS, reinstall
the ICU. (Refer to 5 - BRAKES/HYDRAULIC/ME-
CHANICAL/ICU (INTEGRATED CONTROL UNIT) -
INSTALLATION)
(10) Install the master cylinder. (Refer to 5 -
BRAKES/HYDRAULIC/MECHANICAL/MASTER
CYLINDER - INSTALLATION)
(11) Install the power distribution center.
(12) Connect the negative (ground) cable on the
battery.
(13) Install the air cleaner housing.
(14) Reinstall the air cleaner cover and hose to
throttle body.
(15) Bleed the base brake system and ABS. (Refer
to 5 - BRAKES - STANDARD PROCEDURE)
(16) Road test the vehicle to ensure proper opera-
tion of the brakes.
INSTALLATION - RHD
(1) Install the brake booster on the dash panel
using the reverse of how it was removed. Be certain
dash seal is installed on booster studs prior to instal-
lation.
(2) Under the instrument panel, install the four
power brake booster mounting nuts. Tighten the nuts
to a torque of 34 N·m (25 ft. lbs.).
(3) Using Mopar
t Lubriplate, or an equivalent,
coat the surface of the brake pedal pin where it con-
tacts the brake booster input rod.
PT
BRAKES - BASE
5 - 57
POWER BRAKE BOOSTER (Continued)
CAUTION: Use only a new brake booster input rod-
to-brake pedal retaining clip to ensure proper
retainment.
(4) Connect the power brake booster input rod-to-
brake pedal pin. Install a new retaining clip. Do not
use the old clip.
CAUTION: Do not reuse the original brake lamp
switch. The switch can only be adjusted once. That
is during initial installation of the switch. If the
switch
is
not
adjusted
properly
or
has
been
removed for some service, a new switch must be
installed and adjusted.
(5) Remove and replace the brake lamp switch
with a NEW switch. Discard the original brake lamp
switch. (Refer to 8 - ELECTRICAL/LAMPS/LIGHT-
ING
-
EXTERIOR/BRAKE
LAMP
SWITCH
-
REMOVAL) (Refer to 8 - ELECTRICAL/LAMPS/
LIGHTING - EXTERIOR/BRAKE LAMP SWITCH -
INSTALLATION)
(6) Install the knee blocker.
(7) Install the silencer pad below the knee blocker.
(8) Install the master cylinder on the vehicle.
(Refer to 5 - BRAKES/HYDRAULIC/MECHANICAL/
MASTER CYLINDER - INSTALLATION)
(9) Remove the caps and connect refrigerant lines.
Be certain the sealing O-rings are well lubricated
with PAG oil and free of tears. Torque the retaining
fastener to 40 in. lbs.
(10) Using a R-134a refrigerant recovery machine,
evacuate and charge the refrigerant system. (Refer to
24 - HEATING & AIR CONDITIONING - STAN-
DARD PROCEDURE)
(11) Connect the negative (ground) cable on the
battery.
WARNING:
Be
certain
a
firm
brake
pedal
is
achieved prior to attempting to operate the vehicle.
(12) Road test the vehicle to ensure proper opera-
tion of the brakes.
PROPORTIONING VALVE
DESCRIPTION
NOTE: Only vehicles without antilock brakes have
proportioning valves. Vehicles with antilock brakes
have
Electronic
Variable
Brake
Proportioning
(EVBP) that is built into the integrated control unit.
On the non-antilock master cylinder, two screw-in
proportioning valves are screwed directly into the
rear brake outlet ports (Fig. 117). The chassis brake
tubes leading to the rear brakes attach to the outlets
of the proportioning valves. One proportioning valve
controls each rear brake.
OPERATION
Proportioning valves balance front to rear braking
by controlling the brake fluid hydraulic pressure to
the rear brakes above a preset level (split point).
Under light pedal application, the proportioning
valve allows normal fluid flow to the rear brakes.
Under higher pedal effort, the valve reduces fluid
pressure to the rear brakes. This helps prevent rear
wheel skid tendencies.
DIAGNOSIS AND TESTING - PROPORTIONING
VALVE
NOTE: Only vehicles without antilock brakes have
proportioning valves. Vehicles with antilock brakes
have
Electronic
Variable
Brake
Proportioning
(EVBP) which is built into the ABS Integrated Con-
trol Unit (ICU).
If premature rear wheel skid occurs on a hard
brake application, it could be an indication that a
malfunction has occurred with one of the proportion-
ing valves.
One proportioning valve controls the right rear
brake and the other proportioning valve controls the
left rear brake (Fig. 112). Therefore, a road test to
determine which rear brake skids first is essential.
Before testing the proportioning valve in question,
inspect the rear brake linings for contamination or
for replacement shoes not meeting the OEM brake
lining material specifications.
The proportioning valve should always be tested
prior to being replaced.
Fig. 112 Proportioning Valve Location
1 - RIGHT FRONT BRAKE TUBE
2 - PROPORTIONING VALVES
3 - LEFT FRONT BRAKE TUBE
4 - LEFT REAR BRAKE TUBE
5 - RIGHT REAR BRAKE TUBE
5 - 58
BRAKES - BASE
PT
POWER BRAKE BOOSTER (Continued)
The in-line proportioning valves used on this vehi-
cle require special pressure fittings to test the pro-
portioning valves for proper proportioning valve
function. The pressure fittings are installed before
and after the proportioning valve being tested to ver-
ify proportioning valve is maintaining the required
hydraulic pressure to the rear wheel brake which it
controls.
PROPORTIONING VALVE TEST
The test procedure is the same for either rear pro-
portioning valve. After road testing the vehicle to
determine which wheel skids first, follow the proce-
dure below for testing the suspect proportioning
valve.
(1) Using a brake pedal holding tool as shown (Fig.
113), depress the brake pedal past its first one inch
of travel and hold it in this position. This will isolate
the master cylinder from the brake hydraulic system
and will not allow the brake fluid to drain out of the
master cylinder reservoir.
(2) Use the figure shown to determine which pro-
portioning valve needs to be tested (Fig. 112).
(3) Remove the hydraulic brake tube from the pro-
portioning valve controlling the rear wheel of the
vehicle that has premature wheel skid.
(4) Remove the proportioning valve from its outlet
port on the master cylinder.
CAUTION: Be sure the pressure test fittings being
installed into master cylinder and proportioning
valve, have the correct thread sizes needed.
(5) Install the Brake Pressure Adapters, Special
Tool 8644 and 8187-2 onto the proportioning valve
(Fig. 114).
(6) Install the proportioning valve (with tools) back
into the outlet port on the master cylinder.
(7) Attach
a
Pressure
Gauge,
Special
Tool
C-4007-A, to each pressure adapter (Fig. 115).
(8) Remove the brake pedal holding tool. Bleed any
air out of the pressure gauge hoses at the pressure
gauge.
(9) With the aid of a helper, apply pressure to the
brake pedal until the reading on proportioning valve
inlet gauge is at the target inlet pressure shown in
the Brake Proportioning Valve Applications And
Pressure Specifications table following this proce-
dure. If the inlet gauge pressure overshoots its target
pressure when the pedal is depressed, release the
brake pedal, relieving the pressure in the system,
before reapplying the pedal to reach the target pres-
sure at the inlet gauge. This is necessary to get an
accurate reading of the outlet pressure.
(10) Once inlet pressure has been achieved, check
the pressure reading on the proportioning valve out-
let gauge. If the proportioning valve outlet pressure
does not agree with value shown in the table, replace
the proportioning valve. If proportioning valve is
within pressure specifications, the valve is good and
does not require replacement.
Fig. 113 Brake Pedal Holding Tool
Fig. 114 Tools On Valve
1 - PROPORTIONING VALVE
Fig. 115 Pressure Gauge Set
1 - SPECIAL TOOL C-4007–A
PT
BRAKES - BASE
5 - 59
PROPORTIONING VALVE (Continued)
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