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Old 01-02-2010, 03:58 PM   #1
Murphy IRE
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Join Date: Oct 2009
Location: South Denver Metro, CO
Posts: 385
leak test brake booster

I'm trying to locate vacuum leaks on my 71 K20 400 sbc. I beleive my brake booster may be leaking.

I removed the hose from the intake manifold and hooked up a hand pump . After a bunch of pumping I was only able to pull 15 inches.

I did a search of the threads and did not find an answer to my questions.

They are:

(1) how much vac should I be able to pull on the booster? Does 15 seem low?
(2) once I pull the vac, the booster holds it fine.

Am I missing a step to the leak test? Or does my current test indicate that it is working properly?

Thanks for the help.
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Old 01-02-2010, 09:07 PM   #2
dwcsr
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Location: Houston
Posts: 6,131
Re: leak test brake booster

If the booster holds I would think its ok, the hand pump may be the reason for only 15 .
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Old 01-02-2010, 10:17 PM   #3
68C15
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Re: leak test brake booster

I would put a gauge between the booster and the check valve. start the engine, let it run for a minute and shut it off. the vacuum should hold solid.
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