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 MANUALSCHEVROLET2001CHEVY EXPRESS G2500, VAN CARGO EXTENDED, 5.7 R, L31/KL8REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 11 (DISC BRAKES)SYSTEM TESTSBRAKE SYSTEM VACUUM SOURCE TEST
2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8
Brake System Vacuum Source Test
2001 Chevrolet Chevy Express G2500, Van Cargo Extended, 5.7 R, L31/KL8SECTION Brake System Vacuum Source 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.
- Disconnect the engine vacuum hose from the power brake booster check valve.
- Install a vacuum gauge to the engine vacuum hose.
- Start the engine and allow the engine to idle until normal operating temperatures are reached.
- Check to see if the engine vacuum reading is within the specified normal engine vacuum range. See ENGINE VACUUM RANGE table.
- Turn the ignition off.
- If the engine vacuum reading is within the specified normal range, proceed to step 10 .
- If the engine vacuum reading is NOT within the specified normal range, inspect the engine vacuum hose for the following conditions.
- Tight connection to the engine.
- Collapse, deformation or contamination.
- Cracks, cuts, dry-rot.
- If any of these conditions were found with the engine vacuum hose, replace the hose, then repeat steps 2 - 4 .
- If none of these conditions were found with the engine vacuum hose, then there is an engine vacuum source problem, check the engine vacuum system.
- Remove the power brake booster check valve from the booster.
- Install the check valve to the engine vacuum hose.
- Install the vacuum gauge to the check valve.
- Start the engine and allow the engine to idle until normal operating temperatures are reached.
- Turn the ignition off.
- Check to see if the engine vacuum reading is maintained within the specified normal engine vacuum range. See ENGINE VACUUM RANGE table.
- If the engine vacuum reading is maintained within the specified normal range, proceed to step 18 .
- If the engine vacuum reading is not maintained within the specified normal range, replace the brake booster check valve, then repeat steps 11 - 15 .
- Inspect the brake booster check valve grommet for the following conditions:
- Firm connection to the power brake booster.
- Deformation or contamination.
- Cracks, cuts, dry-rot.
- If any of these conditions were found with the check valve grommet, replace the grommet.
ENGINE VACUUM RANGE
| Specification | Range In. (kPa) |
|---|---|
| Normal Engine Vacuum | 14-20 (47-68) |
RENDER: 1.0x
NO RELATED
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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.