ABS/Brake - Warning Lamps ON When Braking

91chrysler01

SUBJECT: Bosch-Brake and Anti-Lock Warning Lamp Illuminated During Braking


NO.: 05-03-91


GROUP: BRAKES


DATE: Feb. 25, 1991


MODELS: 1990 (AC) DYNASTY/NEW YORKER/LANDAU WITH BOSCH ANTI-LOCK BRAKES

SYMPTOM/CONDITION:


The vehicle must exhibit ALL of the following symptoms:


1. BRAKE and ANTI-LOCK warning lamp illuminates during brake pedal application and extinguishes a few seconds later. If vehicle is in motion as the warning lights extinguish, a series of clicks can be heard as the system goes through its self check.


2. ABS Pump/Motor cycles for 1-2 seconds on brake pedal application.

3. No fault codes are stored.

DIAGNOSIS:

1. Confirm ALL symptoms above.


2. Turn ignition off and discharge the hydraulic accumulator by pumping the brake pedal AT LEAST 25 times.

3. Install hydraulic pressure gauge (Tool # MST-6163).

4. Turn ignition on and note the initial pressure reading. This is the accumulator precharge pressure.

5. If accumulator precharge is below 500 psi, replacement of the accumulator is necessary.

WARNING: BEFORE REMOVING THE PRESSURE TESTER, TURN THE IGNITION OFF AND DISCHARGE THE HYDRAULIC ACCUMULATOR BY PUMPING THE PEDAL AT LEAST 25 TIMES.

PARTS REQUIRED:

1 Accumulator Package PN 4509005


REPAIR PROCEDURE:


This repair procedure involves the replacement of the accumulator.


NOTE: Replacement of the hydraulic accumulator requires removal of the hydraulic assembly from the vehicle. DO NOT ATTEMPT TO REPLACE THE ACCUMULATOR WITH THE HYDRAULIC ASSEMBLY INSTALLED IN THE VEHICLE.


1. With the ignition key in the OFF position, disconnect the negative battery cable.


2. Discharge the hydraulic accumulator assembly by pumping the brake pedal AT LEAST 25 times.


3. Referring to the brake section of the 1990 FWD Car Service Manual, # 81-270-0101, remove the hydraulic assembly from the vehicle.


4. Using a # 30 TORX bit in good condition, carefully remove the accumulator from the hydraulic assembly by removing the two (2) TORX screws underneath the base of the accumulator.


5. Clean the hydraulic assembly in the area of the base of the accumulator, being careful not to get dirt or cleaning fluid in the fluid port.

Figure 1:

6. Lubricate O-ring with clean brake fluid and install on base of accumulator, see Figure 1.


7. Install accumulator to hydraulic assembly using new M6 screws provided in the package and torque to 7-8 N-m (5-6 ft.lbs.)


8. After torquing, turn both screws an additional 90~ (1/4) turn.


9. Reinstall the hydraulic assembly in the vehicle per the service manual instructions.


10. Bleed the brake system using fresh, clean brake fluid.


11. Install the negative battery cable.


12. Restore brake fluid to proper level.


13. Inspect for leaks and verify proper operation.


POLICY: Reimbursable within the provisions of the warranty.

TIME ALLOWANCE:

Labor Operation No. 05-60-02-90 . . . . . . . . . . . . . . . . . . 2.4 Hrs.
FAILURE CODE: 58 - Internal Defect