Subaru 2009 IMPREZA, Service Manual

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BR-47
General Diagnostic Table
BRAKE
19.General Diagnostic Table
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, water or fluid on
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 lining or rotor Correct the cause of fluid leakage, and
clean or replace.
(2) Rotor defective Repair or replace the rotor.
(3) Improper lining contact, deteriorated surface, deterio-
rated or worn lining material Repair by grinding, or replace.
(4) Deformed back plate Correct or replace.
(5) Overinflation of tires Adjust the air pressure.
(6) Defective wheel alignment Adjust alignment.
(7) Loose back plate or support installation bolt Tighten to the specified torque.
(8) Faulty wheel bearing Replace.
(9) Defective hydraulic system Replace the cylinder, brake pipe or hose.
(10) Unstable performance 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 Repair 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)
(creaking sound) (1) Hardened or deteriorated brake pad Replace the pad.
(2) Worn brake pad Replace the pad.
(3) Loose back plate or support installation bolt Tighten to the specified torque.
(4) Loose wheel bearing Tighten to the 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) Improperly 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 support Replace the pad or the support.