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How to find the vacuum leaks, and test system

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Old 12-13-2009, 03:40 PM
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pauldana
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Default How to find the vacuum leaks, and test system

For what it is worth, or anybody ever had this thought....

I went out to Harbor Freight and purchased for ~$70 a vacuum pump, It's original intent was for drawing down the lines on the A/C system. I measured the vacuum level and it holds steady at 17"... cool...

So, I disconnected the engine from the vacuum system and replaced it with a 20' hose (Home Depot) that hooked up to my pump which I placed outside not to hear it run....

Now, in much needed silence I am able to listen for leaks and the such, operate all systems, and work all controls for testing....

It works great!

No engine noise, fumes or any other type of noise,,,,

just a heads up...... found 2 leaks...
Old 12-13-2009, 03:43 PM
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Mike Ward
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Just as easy to connect that 20' hose to a vacuum source on another car sitting outside.
Old 12-13-2009, 04:17 PM
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08vycpe
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pauldana: Good idea. I also have a vacuum pump I use for the A/C system. I'll keep this in mind next time I'm chasing a vacuum leak.
Old 12-13-2009, 04:28 PM
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Originally Posted by Mike Ward
Just as easy to connect that 20' hose to a vacuum source on another car sitting outside.
You get the innovation award of the day. Thats awesome.
Old 12-13-2009, 07:23 PM
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pauldana
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Thx... someone pm'd me for a pic and a few more details, so I thought I would just give it to everyone interested.


DO NOT use the cheap clear hose, it just collapses under the vacuum, instead I went back and got the much thicker hose with thread in it, the one pictured and hooked up, no problems...... opens and closes lights, vents, A/c & heater stuff...... found out, when you have a leak for the heater controls the lights work poorly also... directly tied in.

This does work very well,

Again, just disconnect the vacuum line to the intake manifold and replace with pump line..... Should work for brakes as well!!
Old 12-13-2009, 07:54 PM
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69small block
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Default vac leaks

smoke is a good way to look for leaks ypu can use stick incense and doesnt smell bad of course no breeze also have used air preassure and some bubble leaks detector judt a small regulator to crank air down as to noy blow the lines apart
Old 12-13-2009, 08:16 PM
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Originally Posted by 69small block
smoke is a good way to look for leaks ypu can use stick incense and doesnt smell bad of course no breeze also have used air preassure and some bubble leaks detector judt a small regulator to crank air down as to noy blow the lines apart
tried the pressure thing also, but your controls do not function correctly to check how they are working... this does. Also, any weird smell in my car could not handle that..

Also tried a big craftsmen shop vac... no go, not enough negative pressure.

As far as the second car thing...I see lots of problems there... as i am sure most do.....

this is so simple and works so good..... wish i would have thought of it years ago.. would have save me a lot of trouble.
Old 12-13-2009, 11:39 PM
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Mike Ward
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Originally Posted by pauldana
As far as the second car thing...I see lots of problems there... as i am sure most do......
Like what?
Old 12-14-2009, 12:10 AM
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Originally Posted by Mike Ward
Like what?
more exhaust running, if out side, open to the elements, if inside death from affixation. Having to have 2 cars shut down to diagnose 1. If a bad leak it will effect the car giving vacuum. and I am sure I could think of several others, given another 5 min... not rocket science.


hey, I'm not saying it wont work, and if money is very tight I am sure it will get you by. but it is nice to have the right tool for the right job, I hate to BUBBA things....

To his, his own.... if the duel car thing works for you:chee rs:

I don't mean any offense, Just not like the way I like to do things... thats all.
Old 12-14-2009, 12:19 AM
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Originally Posted by pauldana
For what it is worth, or anybody ever had this thought....

I went out to Harbor Freight and purchased for ~$70 a vacuum pump, It's original intent was for drawing down the lines on the A/C system. I measured the vacuum level and it holds steady at 17"... cool...

So, I disconnected the engine from the vacuum system and replaced it with a 20' hose (Home Depot) that hooked up to my pump which I placed outside not to hear it run....

Now, in much needed silence I am able to listen for leaks and the such, operate all systems, and work all controls for testing....

It works great!

No engine noise, fumes or any other type of noise,,,,

just a heads up...... found 2 leaks...

You are the Man. Thanks for the info. I have a harbor freight just up the road and a few known leaks in both of my cars. This will be a huge help for me.
Old 12-14-2009, 12:48 AM
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Originally Posted by pauldana
If a bad leak it will effect the car giving vacuum........

I hate to BUBBA things....

I don't mean any offense,
Why would it affect the other car if it didn't affect the Corvette?

It takes 10 minutes to properly troubleshoot. 10 minutes of running a car at idle is a bad idea compared to spending 70 bucks on a pump that you'll use once? There's nothing Bubba about using a second car.

You must have a wine and beer making place in town. They rent vacuum pumps normally used for filtering wine. 5 bucks a day usually.

If you don't mean offence, then think twice about what you post.
Old 12-14-2009, 10:28 AM
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Originally Posted by Mike Ward
Why would it affect the other car if it didn't affect the Corvette?

It takes 10 minutes to properly troubleshoot. 10 minutes of running a car at idle is a bad idea compared to spending 70 bucks on a pump that you'll use once? There's nothing Bubba about using a second car.

You must have a wine and beer making place in town. They rent vacuum pumps normally used for filtering wine. 5 bucks a day usually.

If you don't mean offence, then think twice about what you post.
hey... more power to ya..Your right, your idea is brilliant!...

But for those of us like me, that like to wast our money on tools, this works great... :-)
Old 12-14-2009, 11:31 AM
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Originally Posted by pauldana
It's original intent was for drawing down the lines on the A/C system. I measured the vacuum level and it holds steady at 17"... cool...
Paul was this 17" with a leak or without ? My vacuum pump pulls 29.9999999999999 and it crushes any rubber hose so I had to make a valve to maintain about 15. I really hate to run my pump this way and if the one you bought only pulls 17 that would be great.
Old 12-14-2009, 11:36 AM
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Originally Posted by pauldana
As far as the second car thing...I see lots of problems there... as i am sure most do.....
Originally Posted by Mike Ward
Like what?
Like that little SOB down the street from me, he would be in that outside car and gone especially if it was a Vette. I'd like to #$%@^ that little &%^*$.

Merry Christmas to everyone .
Old 12-14-2009, 12:02 PM
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Originally Posted by ...Roger...
Like that little SOB down the street from me, he would be in that outside car and gone especially if it was a Vette. I'd like to #$%@^ that little &%^*$.

Merry Christmas to everyone .

funny...:-)....... yea, mine only pulled down to 15-17"... it was the cheaper pump of the two offered at Harbor Freight

I will also be using this to help with the recharging of the A/C system on the Vett and my truck....O... another use for the tool.....cool..p:-)

Merry Christmas everyone!!!!!!

From Lancaster Ca. USA
Old 12-14-2009, 01:05 PM
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The car-to-car thing is an old mechanic's trick. Good vacuum sources were BB Pontiacs and Oldseys, as they made tons of vacuum. I forgot this tip until this thread!

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