General Diagnostics; Brake System - Subaru LEGACY Service Manual

18.General Diagnostics

A: INSPECTION

1. BRAKE SYSTEM

1. Insufficient braking
2. Unstable or uneven
braking
3. Excessive pedal
stroke
4. Brake dragging or
improper brake return
5. Brake noise (1)
(creak sound)
6. Brake noise (2)
(hissing sound)
7. Brake noise (3)
(click sound)
GENERAL DIAGNOSTICS
Trouble and possible cause
(1) Fluid leakage from the hydraulic mechanism
(2) Entry of air into the hydraulic mechanism
(3) Excessively wide shoe clearance
(4) Wear, deteriorated surface material, adhering
water or fluid on the lining
(5) Improper operation of master cylinder, disc cal-
iper, brake booster or check valve
(1) Fluid on the lining or rotor
(2) Rotor eccentricity
(3) Improper lining contact, deteriorated surface
material, improper inferior material, or wear
(4) Deformed back plate
(5) Improper tire inflation
(6) Disordered wheel alignment
(7) Loosened back plate or the support installing
bolts
(8) Loosened wheel bearing
(9) Trouble in the hydraulic system
(10) Uneven effect of the parking brake
(1) Entry of air into the hydraulic mechanism
(2) Excessive play in the master cylinder push rod
(3) Fluid leakage from the hydraulic mechanism
(1) Insufficient pedal play
(2) Improper master cylinder return
(3) Clogged hydraulic system
(4) Improper return or adjustment of parking brake Correct or adjust.
(5) Weakened spring tension or breakage of shoe
return spring
(6) Excessively narrow shoe clearance
(7) Improper disc caliper operation
(8) Improper adjusted wheel bearing
(1) Hardened or deteriorated lining
(2) Worn lining
(3) Loosened back plate or the support installing
bolts
(4) Loose wheel bearing
(5) Dirty rotor
(1) Worn lining
(2) Improper installed shoe or pad
(3) Loose or bent rotor
(1) Excessively worn pad or the support
(2) Lack of oil on the shoe ridge surface and
anchor
Repair or replace (cup, piston seal, piston boot,
master cylinder piston kit, pipe or hose).
Bleed the air.
Adjust the clearance.
Replace, grind or clean.
Correct or replace.
Eliminate cause of fluid leakage, clean, or replace.
Correct or replace the rotor.
Correct by grinding, or replace.
Correct or replace.
Inflate to correct pressure.
Adjust alignment.
Retighten.
Retighten to normal tightening torque or replace.
Replace the cylinder, brake pipe or hose.
Check, adjust, or replace the rear brake and cable
system.
Bleed the air.
Adjust.
Repair or replace (cup, piston seal, piston boot,
master cylinder piston kit, pipe or hose).
Adjust play.
Clean or replace the cylinder.
Replace.
Replace the spring.
Adjust the clearance.
Correct or replace.
Adjust or replace.
Replace the shoe assembly or pad.
Replace the shoe assembly or pad.
Retighten.
Retighten to normal tightening torque.
Clean the rotor, or clean and replace the brake
assembly.
Replace the shoe assembly or pad.
Correct or replace the shoe assembly or pad.
Retighten or replace.
Replace the pad or the support.
Add more grease.
BR-57
BRAKE
Corrective action