Subaru 2004 LEGACY, Service Manual

Page: 506 / 609

BR-47
BRAKE
Diagnosis
16.Diagnosis
A: INSPECTION
Trouble and possible cause Corrective action
1. Insufficient braking (1) Fluid leakage from the hydraulic mechanism Correct or replace. (cup, piston seal, piston
boot, master cylinder piston kit, pipe or
hose)
(2) Entry of air into the hydraulic mechanism Bleed air.
(3) Wear, deteriorated surface material, adhering water or
fluid on the lining Replace, grind or clean.
(4) Improper operation of master cylinder, disc caliper,
brake booster or check valve Correct or replace.
2. Unstable or uneven
braking (1) Fluid on the lining or rotor Eliminate cause of fluid leakage, and clean
or replace.
(2) Rotor eccentricity Correct or replace the rotor.
(3) Improper lining contact, deteriorated surface material,
improper inferior material, or wear Correct by grinding, or replace.
(4) Deformed back plate Rectify or replace.
(5) Improper tire inflation Adjust to correct pressure.
(6) Disordered wheel alignment Adjust alignment.
(7) Loosened back plate or the support installing bolts Retighten to specified torque.
(8) Faulty wheel bearing Replace.
(9) Trouble in hydraulic system Replace the cylinder, brake pipe or hose.
(10) Uneven effect of the parking brake Check, adjust, or replace the rear brake
and cable system.
3. Excessive pedal
stroke (1) Entry of air into the hydraulic mechanism Bleed air.
(2) Excessive play in the master cylinder push rod Adjust.
(3) Fluid leakage from the hydraulic mechanism Correct or replace. (cup, piston seal, piston
boot, master cylinder piston kit, pipe or
hose)
(4) Improper lining contact or worn lining Correct or replace.
4. Brake dragging or
improper brake
return (1) Insufficient pedal play Adjust play.
(2) Improper master cylinder return Clean or replace the cylinder.
(3) Clogged hydraulic system Replace.
(4) Improper return or adjustment of parking brake Correct or adjust.
(5) Weakened spring tension or breakage of shoe return
spring Replace the spring.
(6) Improper disc caliper operation Correct or replace.
(7) Faulty wheel bearing Replace.
5. Brake noise (1)
(creak sound) (1) Hardened or deteriorated brake pad Replace the pad.
(2) Worn brake pad Replace the pad.
(3) Loosened back plate or the support installing bolts Retighten to specified torque.
(4) Loose wheel bearing Retighten to specified torque.
(5) Dirty rotor Clean the rotor, or clean and replace brake
assembly.
6. Brake noise (2)
(hissing sound) (1) Worn brake pad Replace the pad.
(2) Improper installed pad Correct or replace the pad.
(3) Loose or bent rotor Retighten or replace.
7. Brake noise (3)
(click sound) Excessively worn pad or the support Replace the pad or the support.