how much vacuum?
Thread Starter
Drifting
Joined: Feb 2005
Posts: 1,583
Likes: 5
From: Richardson Tx.
how much vacuum?
should I be able to measure from the Source fitting/line that supplies vacuum to the lines going to A/C controller?
How much is enough to properly open all the gates ?
How much is enough to properly open all the gates ?
Last edited by 79vetter; Jul 24, 2013 at 11:28 PM.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
Yes. But only if you first remove and/or block all hoses that send vacuum to other areas of the car. If one of those lines has a leak in it, then your 'baseline vacuum' reading will be worthless.
Find your baseline reading, then add back one system at a time, while continuing to measure vacuum level. When you add a line back, the vacuum level should not drop more than 1.0" Hg. If it does, there's a leak in that line somewhere downstream. This is one method of tracking-down vacuum leaks.
Find your baseline reading, then add back one system at a time, while continuing to measure vacuum level. When you add a line back, the vacuum level should not drop more than 1.0" Hg. If it does, there's a leak in that line somewhere downstream. This is one method of tracking-down vacuum leaks.
Thread Starter
Drifting
Joined: Feb 2005
Posts: 1,583
Likes: 5
From: Richardson Tx.
Ok - let's say that my vacuum is tight elsewhere - to the headlights etc.
How much vacuum should is adequate/normal at the source T fitting that supplies vacuum to the A/C controller in the dash? I want to take the hose off this fitting and measure with a gauge.
How much vacuum should is adequate/normal at the source T fitting that supplies vacuum to the A/C controller in the dash? I want to take the hose off this fitting and measure with a gauge.
Safety Car
Joined: Mar 2007
Posts: 3,652
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From: Bridgewater nj
12 to 16 hg is normal idle vacuum. Your vac canister should hold the highest vac input and use it as needed for control operations.
The hvac should work as low as 5 hg. It doesn't take much to move a vent flapper.
The hvac should work as low as 5 hg. It doesn't take much to move a vent flapper.
