Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSOLDSMOBILE2004BRAVADA AWDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 22 (DISC BRAKES)SYSTEM TESTSBRAKE SYSTEM INTERNAL LEAK TEST
2004 Oldsmobile Bravada AWD
Brake System Internal Leak Test
2004 Oldsmobile Bravada AWDSECTION Brake System Internal Leak Test
WARNING: This page is about a different car, the 2002 Pontiac Grand Prix and 2002 Oldsmobile Intrigue. However, it is still accessible from the selected car via links, so may be relevant.
- Start the engine and allow it to idle.
- Apply light, steady pressure to the brake pedal. Observe both the brake pedal feel and travel.
- Release the brakes and turn the ignition off.
- If the brake pedal apply felt spongy, but the brake pedal travel was not excessive, perform the following steps:
- Inspect the brake system for external leaks. See BRAKE SYSTEM EXTERNAL LEAK INSPECTION under ADJUSTMENTS & INSPECTIONS.
- Pressure bleed the brake system in order to purge any air that may be trapped in the system. See PRESSURE BLEEDING under BLEEDING BRAKE SYSTEM.
- If the brake pedal apply did not feel spongy, but the brake pedal travel was excessive, perform the following steps:
- Loosen the master cylinder-to-brake power booster mounting nuts.
- Carefully pull the master cylinder away from the brake power booster just enough to inspect the mounting surface of the master cylinder.
- Inspect the master cylinder mounting surface at the primary piston for brake fluid leaks.
- If the master cylinder exhibits any leakage around the primary piston, then the primary piston primary seal and/or secondary seal is leaking and the master cylinder requires overhaul or replacement.
- If the master cylinder primary piston does not exhibit any leakage, pressure bleed the brake system. See PRESSURE BLEEDING under BLEEDING BRAKE SYSTEM.
- If the brake pedal apply did not feel spongy, and the brake pedal travel was initially steady and not excessive, but then gradually fell, then the master cylinder requires overhaul or replacement due to an internal leak past the secondary piston from the secondary piston primary seal or secondary seal.
- If the brake pedal apply did not feel spongy, and the brake pedal travel was initially steady and not excessive, then fell slightly, then became steady again, then the Brake Pressure Modulator Valve (BPMV) may be leaking internally, and may require replacement.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.