Diagnosing a vac leak

[2000ssm6]

I'm leak testing a few saws today and find one that will hold pressure fine but can't when applying vacuum. I've read that crank seals are the most likey cause but how can I determine where a vac leak is vs pressure with soapy water.

Thanks

 

[paragonbuilder]

Spray it with oil. It should slow down or stop the leak. It's thicker.


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[Magic_Man]

I spray a little wd40 around the seal and watch for the vacuum to draw it in.

 

[lumberjackchef]

I had one the other day that did the same thing. I found that if I turned the crank or applied pressure downward it would the reveal the leak...

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[2000ssm6]

Thanks guys, used some earl around the crank seals and got it.