How to test vacuum system??

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Aug 11, 2012 | 08:47 AM

GT's 78

Thread Starter

Racer

Joined: Sep 2010

Posts: 259

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From: Mt Airy, NC

How to test vacuum system??

Without the use of the engine how could I hook up some vacuum to test everything vacuum operated such as switches, HVAC doors, lights, etc... I would like to test everthing before I completly reassemble. Thanks

Aug 11, 2012 | 08:54 AM

oldalaskaman

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one of those hand operated vacuum brake bleeders would work, an a/c vacuum pump, and with a long enough vacuum hose another car with the engine running, used to do that with lincoln headlights.

Aug 11, 2012 | 10:14 AM

scottyp99

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Joined: Mar 2008

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From: Oxford MA-----You just lost the game!!!!

http://www.harborfreight.com/brake-b...kit-92474.html

It's a very useful tool. You can use it to bleed brakes, measure manifold vacuum, check the vacuum hoses for leaks, etc.
Here are a coiple of articles on using a vacuum gauge to diagnose engine problems.

http://www.youtube.com/watch?v=utUSI-JYhVU

http://autospeed.com/cms/title_Using...3/article.html

Keep the shiny side up!

Scott

Aug 11, 2012 | 01:42 PM

7t2vette

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From: Toronto Ontario

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I wouldn't waste my time with one of those hand held vacuum pumps, you just can't continuously create enough vacuum with them for what you want to do.

If you know someone that does AC work, they will have a vacuum pump that would work. In the past, I have used a long piece of vacuum hose to connect to another vehicle's running engine. I also have used a small tire inflator that I rigged a hose to the intake to create vacuum.

http://www.instructables.com/id/conv...ressor-into-a/

Aug 11, 2012 | 02:06 PM

Dave J

Drifting

Joined: Jul 2006

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From: Deplorableville Nebraska

I've had great success using a Mityvac hand vacuum pump to test the seals on individual components, and proper operation of vacuum switches. It also works very well as a leak down test for any vacuum component seal. If you're looking to imitate constant vacuum, here's a couple of links for ya....

http://forums.corvetteforum.com/c3-g...ne-vacuum.html

http://forums.corvetteforum.com/c3-g...t-sharing.html

Aug 11, 2012 | 03:04 PM

7T1vette

Team Owner

Joined: Jan 2006

Posts: 37,637

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From: Crossville TN

You cannot test the complete system with one of those hand-pump vacuum units. But, you can test an individual run of vacuum line or a single vacuum device with it. You just need to understand where to connect the vacuum pump, what fittings to block off, and what result ('open' or 'vacuum') you should get with each test. So, with a MightyVac and several small squeeze clamps, you can check out the entire system fairly easily. {once you get access to the test points you need, of course}

But, if the engine is operational, it is the best vacuum source for testing the system.

Aug 12, 2012 | 09:26 AM

GT's 78

Thread Starter

Racer

Joined: Sep 2010

Posts: 259

Likes: 1

From: Mt Airy, NC

Thanks for the replies guy's. I think I'm going to try another car's vacuum, I didn't even concider that.

Aug 12, 2012 | 09:54 AM

69 Chevy

Melting Slicks

Joined: Aug 2008

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From: Lehigh county Pennsylvania

http://www.harborfreight.com/air-vac...ors-96677.html

This gizmo works very well for me although, obviously you need an air compressor to operate it. I took it out of the red plastic case and eliminated the A/C fittings.