check valve or what

[GERALD]

On my 79 behind the carb on top of intake what is the white plastic peace mounted in the vacum line is this a check valve or what is this for whats it 's purpose

 

[ssvett]

Gerald, It's a filter. I don't know what it filters, but that's what it is............Steve

 

[mz0dxc]

Check valve or what

If the vacuum line your are talking about goes to the brake booster, it is a check valve to protect the booster from fuel vapors and backfires. It will flow with vacuum on it but will check if it gets a pressure pulse such as a backfire and it will close when the engine is off to prevent fuel vapor from entering the brake booster and destroying the diaphram.

 

[GERALD]

It's the vacum hose that go's threw the fire wall

 

[1979toy]

If you've got 1 vacuum line going in from the manifold and 2 going out, 1 to the dash and 1 to the headlights then it's the one-way check valve. Keeps pressure in the headlight system when the engine is shut off I think.