1981 vacuum line question

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Oct 13, 2013 | 03:42 PM

rsnyderjr2

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From: Gowrie IA

1981 vacuum line question

Hi Guys - can someone please tell me what this silver thing is / does on my vac line to the intake manifold? (I know the white one is a filter)...

Tired of paging through my service manual trying to find it... :P

Thanks!!

Ritch

Oct 13, 2013 | 04:21 PM

Jig A Low

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From: Chesapeake Virginia

it's a check valve, that attempts to hold the vacuum created in the system when you shut the engine off.

Oct 13, 2013 | 05:21 PM

DUB

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From: Charlotte NC

Quote:

Originally Posted by Jig A Low

it's a check valve, that attempts to hold the vacuum created in the system when you shut the engine off.

This check valves purpose is to make the system hold vacuum while the engine is running so all of your operated vacuum components work correctly at their setting. Because engine vacuum values change under different throttle angles...these components can go back to a "natural" setting if vacuum is lost. So..this check valve in conjunction with the vacuum storage tank in between your headlights holds the vacuum stored when the engine is not producing a high vacuum to keep it supplied. Because without this check valve...you are at the mercy of the engine providing vacuum...which can make the vacuum operated doors in your HVAC system to go back to the "natural state...and you wonder why you loose defroster at times...and then it comes back again....for example.

And YES...if your system is TIGHT and free from major leaks. You should be able to run your engine for a short while...turn your engine off...wait about one minute...and then go in and pull your headlight switch...and raise the headlights...OR... if you left your headlights on when you shut the engine off....wait... then turn off your headlights and the doors should go down.

DUB

Oct 13, 2013 | 07:18 PM

rsnyderjr2

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From: Gowrie IA

Cool - thanks guys!

Oct 14, 2013 | 09:02 AM

Easy Mike

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From: Southbound

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The assembly instruction manual (AIM) shows the valve and the vacuum hose routing. AIMS are nice to have around. Order one.

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