Chrysler PT Cruiser. Manual — part 427
(11) Reinstall the brake holding tool on the brake
pedal and remove the test equipment from the vehicle.
(12) Remove the tools from the proportioning
valve.
(13) Install the proportioning valve in the master
cylinder and hand tighten until the proportioning
valve is fully installed and its O-ring seal is seated
into the master cylinder. Tighten the proportioning
valve to a torque of 40 N·m (30 ft. lbs.).
(14) Install the brake tube on the proportioning
valve. Tighten the tube nut to a torque of 17 N·m
(145 in. lbs.).
(15) Bleed the affected brake line. (Refer to 5 -
BRAKES - STANDARD PROCEDURE)
BRAKE PROPORTIONING VALVE APPLICATIONS AND PRESSURE SPECIFICATIONS
SALES
CODE
BRAKE SYSTEM
TYPE
SPLIT
POINT
SLOPE
INLET PRESSURE
OUTLET PRESSURE
BRB
15 In. Disc/Drum
380 psi
0.27
1000 psi
500-600 psi
REMOVAL
NOTE: Before proceeding, (Refer to 5 - BRAKES -
WARNING) (Refer to 5 - BRAKES - CAUTION).
(1) Using a brake pedal holder, depress the brake
pedal past its first one inch of travel and hold it in
this position (Fig. 116). 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.
NOTE: To access the lower (left rear) proportioning
valve, it may help to remove the air cleaner cover
and hose to the throttle body.
(2) Disconnect the brake tube from the proportion-
ing valve requiring removal (Fig. 117).
(3) Unscrew the Proportioning valve from the mas-
ter cylinder.
INSTALLATION
(1) Lubricate the O-ring on the proportioning
valve. Make sure the O-ring on the proportioning
valve is new.
(2) Install the proportioning valve in its master
cylinder port. Tighten the proportioning valve to a
torque of 40 N·m (30 ft. lbs.).
(3) Connect the brake tube to the proportioning
valve (Fig. 117). Tighten the tube nut to a torque of
17 N·m (145 in. lbs.).
NOTE: Reinstall the air cleaner cover and hose if
earlier removed to gain more access to the lower
(left rear) proportioning valve.
(4) Remove the brake pedal holder (Fig. 116).
(5) Bleed the affected brake line. (Refer to 5 -
BRAKES - STANDARD PROCEDURE)
(6) Road test the vehicle to ensure proper opera-
tion of the brakes.
Fig. 116 Brake Pedal Holder
Fig. 117 Proportioning Valves On Master Cylinder
1 - RIGHT FRONT BRAKE TUBE
2 - PROPORTIONING VALVES
3 - LEFT FRONT BRAKE TUBE
4 - LEFT REAR BRAKE TUBE
5 - RIGHT REAR BRAKE TUBE
5 - 60
BRAKES - BASE
PT
PROPORTIONING VALVE (Continued)
ROTOR
DESCRIPTION
There are two different size rotors available
depending on brake application. Vehicles with the
brake sales code BRB and BRK (Disc/Drum combina-
tions) and BRT (Disc/Disc combination) use standard
size brake rotors. Vehicles equipped with the brake
sales code BR4 (Performance Disc/Disc combination)
use heavier brake rotors. The BR4 front brake rotor
is approximately 5 mm thicker than the standard
front brake rotor. The BR4 rear brake rotor is
approximately 3 mm thicker than the standard rear
brake rotor. The BR4 brake rotors can be easily iden-
tified by the recessed machined area near the hub
center (Fig. 118) (Fig. 119).
DIAGNOSIS AND TESTING - BRAKE ROTOR
Any servicing of the rotor requires extreme care to
maintain the rotor within service tolerances to
ensure proper brake action.
Excessive runout or wobble in a rotor can increase
pedal travel due to piston knock-back. This increases
guide pin sleeve wear due to the tendency of the cal-
iper to follow the rotor wobble.
When diagnosing a brake noise or pulsation, the
machined disc braking surface should be checked and
inspected.
BRAKING SURFACE INSPECTION
Light braking surface scoring and wear is accept-
able. If heavy scoring or warping is evident, the rotor
must be refaced or replaced. (Refer to 5 - BRAKES/
HYDRAULIC/MECHANICAL/ROTOR - STANDARD
PROCEDURE)
Excessive wear and scoring of the rotor can cause
improper lining contact on the rotor’s braking sur-
face. If the ridges on the rotor are not removed before
new brake shoes are installed, improper wear of the
shoes will result.
Fig. 118 Front Brake Rotor Comparison
1 - BRB/BRT BRAKE ROTOR
2 - STANDARD ROTOR THICKNESS
22.91-23.10 MM
3 - PERFORMANCE ROTOR THICKNESS
27.91-28.10 MM
4 - BR4 PERFORMANCE BRAKE ROTOR
5 - INDENTIFYING MACHINED AREA
Fig. 119 Rear Brake Rotor Comparison
1 - BRT BRAKE ROTOR
2 - STANDARD ROTOR THICKNESS
8.75-9.25 MM
3 - PERFORMANCE ROTOR THICKNESS
11.75-12.25 MM
4 - BR4 PERFORMANCE BRAKE ROTOR
5 - INDENTIFYING MACHINED AREA
PT
BRAKES - BASE
5 - 61
If a vehicle has not been driven for a period of
time, the rotor’s braking surface will rust in the
areas not covered by the brake shoes at that time.
Once the vehicle is driven, noise and chatter from
the disc brakes can result when the brakes are
applied until the rust wears away.
Some discoloration or wear of the rotor surface is
normal and does not require resurfacing when lin-
ings are replaced. If cracks or burned spots are evi-
dent, the rotor must be replaced.
ROTOR MINIMUM THICKNESS
Measure rotor thickness at the center of the brake
shoe contact surface. Replace the rotor if it is worn
below minimum thickness or if machining the rotor
will cause its thickness to fall below specifications.
CAUTION: Do not machine (turn) the rotor if it will
cause the rotor to fall below minimum thickness.
Minimum thickness specifications are cast on the
rotor’s unmachined surface (Fig. 120) (or stamped
into the hat section). Limits can also be found in this
section’s specification table. (Refer to 5 - BRAKES/
HYDRAULIC/MECHANICAL/ROTOR - SPECIFICA-
TIONS)
ROTOR THICKNESS VARIATION
Thickness variation in a rotor’s braking surface
can result in pedal pulsation, chatter and surge. This
can also be caused by excessive runout in the rotor or
the hub.
Rotor thickness variation measurements should be
made in conjunction with measuring runout. Mea-
sure thickness of the brake rotor at 12 equal points
around the rotor braking surface with a micrometer
at a radius approximately 25 mm (1 inch) from edge
of rotor (Fig. 121). If thickness measurements vary
beyond the specification listed in the specifaction
table (Refer to 5 - BRAKES/HYDRAULIC/MECHAN-
ICAL/ROTOR - SPECIFICATIONS), the rotor should
be refaced or replaced. (Refer to 5 - BRAKES/HY-
DRAULIC/MECHANICAL/ROTOR
-
STANDARD
PROCEDURE)
ROTOR RUNOUT
On-vehicle rotor runout is the combination of the
individual runout of the hub face and the runout of
the rotor. (The hub and rotor runouts are separable).
To measure rotor runout on the vehicle, first remove
the tire and wheel assembly. Reinstall the wheel
mounting nuts on the studs, tightening the rotor to
the hub. Mount the Dial Indicator, Special Tool
C-3339, with Mounting Adaptor, Special Tool SP-1910
on steering arm. The dial indicator plunger should
contact braking surface of rotor approximately 25
mm (1 inch) from edge of rotor (Fig. 122). Check lat-
eral runout on both sides of the rotor, marking the
low and high spots on both. Runout limits can be
found in the specification table in this section. (Refer
to 5 - BRAKES/HYDRAULIC/MECHANICAL/RO-
TOR - SPECIFICATIONS)
If runout is in excess of the specification, check the
lateral runout of the hub face. Before removing the
rotor from the hub, place a chalk mark across both
the rotor and the one wheel stud closest to where the
high runout measurement was taken. This way, the
original mounting spot of the rotor on the hub is
indexed (Fig. 123).
Remove the rotor from the hub.
Fig. 120 Minimum Brake Rotor Thickness Markings
(Typical)
1 - ROTOR MINIMUM THICKNESS MARKING
2 - ROTOR
Fig. 121 Checking Rotor Thickness
1 - MICROMETER
5 - 62
BRAKES - BASE
PT
ROTOR (Continued)
NOTE: Clean the hub face surface before checking
runout. This provides a clean surface to get an
accurate indicator reading.
Mount Dial Indicator, Special Tool C-3339, and
Mounting Adaptor, Special Tool SP-1910, to the steer-
ing knuckle. Position the indicator stem so it contacts
the hub face near the outer diameter. Care must be
taken to position stem outside of the stud circle, but
inside of the chamfer on the hub rim (Fig. 124).
Hub runout should not exceed 0.08 mm (0.003
inch). If runout exceeds this specification, the hub
must be replaced. For front hub removal, (Refer to 2
- SUSPENSION/FRONT/KNUCKLE - REMOVAL).
For rear hub removal, (Refer to 2 - SUSPENSION/
REAR/HUB / BEARING - REMOVAL).
If the hub runout does not exceed this specifica-
tion, install the rotor back on the hub, aligning the
chalk marks on the rotor with a wheel mounting
stud, two studs apart from the original stud (Fig.
125). Tighten nuts in the proper sequence and torque
to specifications.
Recheck brake rotor runout to see if the runout is
now within specifications. (Refer to 5 - BRAKES/HY-
DRAULIC/MECHANICAL/ROTOR
-
SPECIFICA-
TIONS)
If runout is not within specifications, reface or
replace the brake rotor. (Refer to 5 - BRAKES/HY-
DRAULIC/MECHANICAL/ROTOR
-
STANDARD
PROCEDURE)
Fig. 122 Checking Rotor Runout
1 - SPECIAL TOOL SP-1910
2 - 25mm FROM EDGE
3 - DISC SURFACE
4 - SPECIAL TOOL C-3339
Fig. 123 Marking Rotor and Wheel Stud
1 - CHALK MARK
Fig. 124 Checking Hub Runout
1 - HUB SURFACE
2 - SPECIAL TOOL C-3339
3 - SPECIAL TOOL SP-1910
PT
BRAKES - BASE
5 - 63
ROTOR (Continued)
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