Brake System Inspection and Test

Inspect the brake system components listed. Repair or replace any parts that are leaking or damaged.

Component Inspections:
Component Procedure Also check for 
Master Cylinder Look for damage or signs of fluid leakage at:
  • Reservoir tank, reservoir union or master cylinder body.
  • Lines, reservoir tank hose and grommets, and their joints
  • Between master cylinder and booster
 
Bulging seat at reservoir cap. This is a sign of fluid contamination. 
Brake Hoses Look for damage or signs of fluid leakage at:
  • Line joints and banjo bolt connections
  • Hoses and lines, also inspect for twisting or damage
 
Bulging, twisted, or bent lines. 
Caliper Look for damage or signs of fluid leakage at:
  • Piston seal
  • Banjo bolt connections
  • Bleed screw
 
Seized or sticking caliper pins. 
Wheel Cylinder Look for damage or signs of fluid leakage at:
  • Wheel cylinder
  • Line joints
  • Bleed screw
 
 
ABS or VSA Modulator-control Unit Look for damage or signs of fluid leakage at:
  • Line joints
  • Modulator-control unit
 
 

Brake System Test


Brake pedal sinks/fades when braking


1.Set the parking brake, and start the engine, then turn off the A/C switch. Allow the engine to warm up to normal operating temperature (radiator fan comes on twice).

2.Attach a 50 mm (2 in.) piece of masking tape along the bottom of the steering wheel, and draw a horizontal reference mark across it.

3.With the transmission M/T in neutral position, A/T in P or N position, press and hold the brake pedal lightly (about the same pressure needed to keep an A/T-equipped vehicle from creeping), then release the parking brake.

4.While still holding the brake pedal, hook the end of the tape measure behind the brake pedal, then pull the tape up to the steering wheel. Note the measurement between the brake pedal and the reference mark on the steering wheel.

5.Apply steady pressure to the brake pedal for 3 minutes.

6.Watch the tape measure.

  • If the measurement increases 10 mm (0.39 in.) or less, the master cylinder is OK.
  • If the measurement increases more than 10 mm (0.39 in.), replace the master cylinder.