vacuum leak? maybe break booster?

[kelz702]

Hello All!
First off I'd like to say this form has helped me out tremendously over the years. The knowledge and know how is next to none.
I have a 72 c20 rebuilt 350, old th300. I've been trying to track down what I believe to be a vacuum leak. After doing some searching, I found out about break boosters causing vacuum leaks due to a torn diaphragm.
The truck idles prefect accept for when I'm stopped at a light for a few minutes. It then start to surge. As soon as I accelerate, the surge goes away. Only when I stop at a light again, it starts back up. It only happens when I have the breaks on for over a few mins. On short stops, there is no problem.
Today I took the vacuum hose going to the booster off while it was surging. I had it on my street with the ebrake on, chucks under the tires, and in drive. Once I plugged the hose the idle went up and the surge went away.
Does this sound like I need to replace my break booster due to a torn diaphragm?
Thanks,
Kelz
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