How do I find a vacuum leak?

Answer 1

I would lather up the hose with soap bubbles. It will show you where the leak is.

Answer 2

Very low pressure air is used to test vacuum lines along with a manometer that will show if the slightest leak is present. Use a pump up bulb similar to that kind used on a blood pressure machine to pump up. Make a "U" tube manometer out of clear vinyl tubing, staple that to a piece of plywood and set up vertical, then fill with water and then run the test. the manometer will indicate even the slightest leak in just a minute or two. If holes are found, then soap test as below.

Soap test at very low pressure will make huge bubbles out of minute hose leaks. I used to test vacuum lines that ran several feet using hoses. What I found is that ordinary commercial vinyl braided hose is like a sieve. One needs to purchase a higher grade of vinyl hose known as "aircraft" quality. In that hose, still, I would find minute holes in the low pressure test prior to installing them on hospital equipment where they had to quarantee a low vacuum without leaks. .

Answer 3

If you're talking about on a car, I've used WD40. With the car running, take care not to spray on hot exhaust. Spray around intake gasket and vacuum hoses. Move slowly, and if you spray on a leak, the engine will speed up, as the propellant in the WD40 will act as a fuel.

Answer 4

Perhaps you could apply a little water at suspicious points and if the leak stops you have found it. Without knowing what is being used, it is difficult to come up with a solution.

Answer 5

Could you tell us what's leaking? It would help get an answer. If this question gets buried, repost it with more detail. I'd try to figure out what you could do if I knew more. If it's a car problem, try posting in automotive maintenance and repairs.