Find vacuum leak?
Le Mans Master
Joined: Sep 2002
Posts: 5,236
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From: Myrtle Beach SC
I use a vacuum pump and golf tees to plug lines that I am troubleshooting. A vacuum troubleshooting guide use to be at the top but it seems to have disappeared. Do a search on "vacuum troubleshooting" and you should be able to track it down. You can then troubleshooting vacuum systems. You may get lucky by just using the vacuum pump (Mity Vac), start at the vacuum port at the back of the carb on the manifold, and listen with the motor off. Here's a link to Mity Vac
https://www.skf.com/mityvac/products...pressure-pumps
https://www.skf.com/mityvac/products...pressure-pumps
Race Director
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Vacuum leak at engine? Or down the line? At engine is one test. Down the lines another. Try unplugging the main vacuum line to your Healight/Hyvc system first. No hissing? Or just check manifold/ Carb for vacuum leaks. Do you own a vacuum gauge?
Thread Starter
Instructor
Joined: Jun 2019
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Down the line,,, I think
Is the main vacuum line to the headlights etc... at the intake behind the carb?
I don't hear it every time that I shut down. It seems to come and go, and it is very quiet and only lasts maybe a second or so. The headlights come up and go down at what seems a normal speed, but one at a time.
Thank you for your help.
Burning Brakes
Joined: Dec 2008
Posts: 971
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From: Middlesex NJ
If its in the car and you hear it when you shutdown... check the elbows on the bypass switch(s) under the column.
One of my elbows was really dried up and leaking on the bypass switch. You could hear right after you shut the key off while in the car.
As far as smoke machines go... search on ebay for automotive smoke machine. I got one that looks like a paint sprayer cup works great they run about $100. There are cheaper ones made of paint cans depends how much your gona use it.
One of my elbows was really dried up and leaking on the bypass switch. You could hear right after you shut the key off while in the car.
As far as smoke machines go... search on ebay for automotive smoke machine. I got one that looks like a paint sprayer cup works great they run about $100. There are cheaper ones made of paint cans depends how much your gona use it.
Last edited by mysixtynine; Oct 16, 2020 at 02:43 PM.
Team Owner
Joined: Jan 2006
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From: Crossville TN
You might hear hissing when tank, etc which hold vacuum start drawing in air upon engine shutdown. Some vacuum system items have a 'vent' in them to equalize pressure. The wiper solenoid/switch attached to the tachometer is one of them. Another is the wiper park switch mounted under the right-side wiper blade.
If 'things' are working properly, ignore the hiss....
If 'things' are working properly, ignore the hiss....
Last edited by 7T1vette; Oct 16, 2020 at 07:12 PM.
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A stethoscope of some sort helps a lot. If you dont have a mechanics scope take a small diameter piece of hose that is long enough to get into the engine bay and have someone shut off the car. You can poke around with it and its amax=zing how well a hose in your ear can help narroe a noise down to its source. I havve a vacuum pump that I use to create a vacuum in my vacuum lines so that I done have to use the car as a source. I create a good vacuum then shut it off and listen. Start up the pump again, shut it off and listen somewhere else. I helped alot
