How do I know if my vacuum check valve is bad?

[silvermouse523]

Symptoms of a Bad or Failing Vacuum Brake Booster Check Valve

1. Brake pedal is difficult to engage. When the vacuum brake booster check valve is working correctly, applying pressure to the brake pedal is easy and very smooth.
2. Brakes feel spongy.
3. Brakes stop working.

[happyduck881]

1. Firm Brake Pedal This is what happens when the check valve is working just fine. But if the check valve is worn out and no longer working, then it might cause your brake pedal to become more difficult to push down. The pedal will suddenly feel firm and itll take a lot more foot pressure than normal to push it down.

Also, what does a vacuum check valve do? A vacuum check valve will only allow air to move in one direction. There is a check valve on the brake booster line coming off of the intake manifold that does not allow the vacuum that the booster needs to bleed off when under a WOT condition (no vacuum). It may be used for different things elsewhere.

Consequently, how do you test a vacuum check valve?

Vacuum Inlet Check Valve Test: To test the vacuum check valve, disconnect the vacuum supply hose from the intake manifold or vacuum pump, and blow into the hose. If air passes through the valve into the booster, the check valve is defective and should be replaced.

How do you change a vacuum booster on a check valve?

Part 1 of 1: Replacing the vacuum brake booster check valve

1. Materials Needed.
2. Step 1: Open the hood.
3. Step 2: Locate the brake booster check valve.
4. Step 3: Remove a gear type clamp.
5. Step 4: Remove a spring type clamp.
6. Step 5: Remove the brake booster vacuum hose.
7. Step 6: Remove the vacuum brake booster check valve.