Front Brakes - Pedal Pulsation

NO: 05-03-98 Rev A.

GROUP: Brakes

DATE: Aug. 28, 1998

SUBJECT:
Disc Brake Rotor
Pulsation

NOTE:
THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETIN NUMBER 05-03-98 DATED APRIL 3, 1998 WHICH SHOULD BE REMOVED FROM YOUR FILES. THE BULLETIN ADDS 1999 MODELS AND CORRECTS A REFERENCE TO THE USE OF THIS MATERIAL IN EARLIER MODELS. THE CHANGES ARE HIGHLIGHTED WITH ASTERISKS.

MODELS:
1997 - **1999** (XJ) Cherokee
1997 - **1999** (TJ) Wrangler
1997 - 1998 (ZJ) Grand Cherokee

SYMPTOM/CONDITION:

The vehicle may exhibit minor brake pedal pulsation which may be caused by rough disc rotors. This condition will usually occur in warm climate, high humidity areas. Chemical material from the brake pads can transfer to the rotors causing enough surface friction variation or uneven rotor wear to induce this rough feel.

DIAGNOSIS:

Road test the vehicle at highway speeds with light brake application. If the vibration is felt in the brake pedal, steering wheel or body, inspect the rotors. Often, the rotors will appear discolored or darker in areas. If this is present, perform the Repair Procedure.

NOTE:
THE BRAKE PADS USED IN THIS REPAIR ARE MADE WITH THE SAME FRICTION MATERIAL USED IN PRODUCTION ON ** 1996 ** VEHICLES. THE CURRENT PADS WERE RELEASED AS AN IMPROVEMENT TO MINOR BRAKE NOISE ISSUES SUCH AS SQUEAL AND CREEP GROAN. THE REPLACEMENT PADS MAY BE MORE SUSCEPTIBLE TO THESE ISSUES. THE REPLACEMENT PADS HAVE A HIGHER METALLIC CONTENT WHICH OFFERS BETTER CHARACTERISTICS RELATIVE TO SELF CLEANING OF THE ROTORS.

PARTS REQUIRED:

1 04778058AB Brake Pad Kit

REPAIR PROCEDURE:

This bulletin involves turning the brake rotors and installing new brake pads.

1. Measure the brake rotors to verify that the rotors can be turned and still remain within the specification for minimum thickness. The specification for minimum thickness is either stamped or cast into the rotor hub. If the rotors can be turned, it is recommended that approved, on the car turning equipment be used. Do not use off the car rotor turning equipment. Replace any rotors not suitable for turning.

2. Remove the calipers and install the new brake pads, p/n 04778058AB, using the procedures outlined in the appropriate service manual.

POLICY: Reimbursable within the provisions of the warranty.

TIME ALLOWANCE:

Labor Operation No:

05-21-10-96 Rotor - Replace 0.6 Hrs.
05-21-11-91 Rotor - Reface 1.1 Hrs.
05-70-22-50 Disc Pads - Replace 0.4 Hrs.

FAILURE CODE: P8 - New Part