Brake Caliper Leakage Diagnosis (06-90-24)

Publication date: 2024-06-25
Reference number: 06-90-24

BRAKE CALIPER LEAKAGE DIAGNOSIS

TECHNICAL SERVICE BULLETIN

Reference Number(s): 06-90-24, Date of Issue: June 25, 2024

SUBARU:

All Models

APPLICABILITY

All Models

INTRODUCTION

This bulletin provides diagnosis and procedure information to be applied when diagnosing potential fluid leaks on front and rear brake calipers. This information has been developed to reduce unnecessary brake caliper replacement.

SERVICE PROCEDURE/INFORMATION

Personal Protection Equipment (PPE): Always observe safety precautions when diagnosing and servicing the brake system. Refer to the appropriate service information for safety cautions and warnings when accessing or removing brake system components.

IMPORTANT: Residual caliper assembly grease applied during vehicle production may in some cases be mistaken for a brake fluid leak. Over time, grease around the pistons, boots and calipers may develop a dirty/oily appearance. This condition is considered normal and does not require any further repair. See the EXAMPLE images below and refer to the inspection procedure information outlined on the next page to ensure the caliper is operating as designed and no actual brake fluid leakage is present.

All of the EXAMPLE images below depict assembly grease misdiagnosed as brake fluid loss.

BRAKE FLUID LEAKAGE INSPECTION PROCEDURE

STEP 1: Prepare the caliper(s) by cleaning the surrounding area. It important to use CAUTION when cleaning and ALWAYS wear eye protection. Abrasive materials and excessive force may cause damage to piston boots. Subaru Low VOC Brake Cleaner (p.n. SOA868V9110 ) is the recommended cleaner be used to clean the caliper(s). California based retailers are recommended to use Subaru California Brake Cleaner (p.n. SOA868V9116 ). This is specifically formulated to meet California VOC standards.

NOTE: Both brake cleaner types can also be or in bulk 53 Gallon drums. The bulk part number are listed below.

Subaru Low VOC Brake Cleaner (p.n. SOA868V9111 )
Subaru California Brake Cleaner (p.n. SOA868V9126 )

STEP 2: A second person or a brake depressor tool will be required to depress the brake pedal.

NOTE: A Hunter® (p.n. WA15-S ) Brake Pedal Depressor is shown in the EXAMPLE image to the right.

If the vehicle is equipped with an electric brake booster, turn ON the ignition switch and firmly apply brake pedal pressure for ten seconds. If equipped with a negative pressure (vacuum) brake booster , the engine must be running with brake pedal pressure firmly applied for ten seconds.

The image below is an EXAMPLE of a brake fluid leakage requiring repair.

STEP 3: Has brake fluid leakage been detected?

YES: Replace the affected caliper(s) and perform the brake system bleeding procedure as per the applicable Service Manual.

NO: No further service is required.

WARRANTY/CLAIM INFORMATION

Refer to the Labor Time Guide for vehicle model, applicable repair, and claim specific information.

IMPORTANT REMINDERS:

SOA strongly discourages the printing and/or local storage of service information as previously released information and electronic publications may be updated at any time.
Always check for any open recalls or campaigns anytime a vehicle is in for servicing.
Always refer to STIS for the latest service information before performing any repairs.