Vacuum or boost bleed off noise when crawling in 1st gear

CJ-

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is it normal to hear a boost or vacuum bleed off sound as I’m moving the gt500 around the driveway? I’ll hear this swooshing sound while crawling forward in 1st gear and while reversing.
 

CJ-

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I’m almost certain the vacuum bleeding sound is coming from a clutch booster cause I hear the vacuum bleed/leak as I’m pressing or releasing the clutch pedal. And while I’m at a stop, I’ll have to pump the clutch pedal 3 times until I stop hearing the hiss of vacuum through the clutch pedal.
 

01yellerCobra

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AFAIK there is no vacuum hooked up to the clutch master cylinder. If it's really hissing from around the clutch pedal I'd start looking for fluid leaks.
 

redfirepearlgt

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^^^ The clutch pedal displaces fluid from the res. to the slave cylinder to disengage the clutch. In fact you can buy res. that will separate the clutch system from the braking system and there is no vacuum mods to be made. I agree with the good man from SD, that you may wish to look for potential leaks around the clutch pedal actuator if there is a problem at all. It just may be something you only recently noticed. Happens to me all the time. I drive most of the time with windows down, air off, and radio on. It's when I have radio off, AC on and windows up I start hearing things I thought were never there before. Sometimes it's just me, sometimes its due to recent mods, sometimes it;s actually an issue.
 

CJ-

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I’ll try to post a video so you can hear what I’m talking about. It’s sorta difficult to discribe but the hissing is loud and can be heard clearly through both windows.

Does the supercharger have some sort of vacuum controlled bov or pressure relief valve?
 

01yellerCobra

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Yes it does. It should be on the side of the blower. But the clutch won't affect that at all.

What clutch is in the car? I have a Mcleod twin disc and there's a hissing sound right when it's starting to catch. It's normal for these clutches.
 
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travelers

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Yes
Yes it does. It should be on the side of the blower. But the clutch won't affect that at all.

What clutch is in the car? I have a Mcleod twin disc and there's a hissing sound right when it's starting to catch. It's normal for these clutches.

You got that answer out before I could.
 

RocketcarX

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The brake booster would make this noise from the same basic area. Chances are you are on the brakes and the clutch at the same time so it would seem like a clutch noise when in reality the brake booster is leaking vacuum when you press the brake pedal. Its something to check anyhow.
 

travelers

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A way to test the vacuum system is put a vacuum gauge in the system and press on the brake peddle and see if you continue to loose vacuum. You will see some loss when you push on the peddle at first but should build back up as you hold the peddle at one position. If not you have a booster leak.
 

RocketcarX

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A way to test the vacuum system is put a vacuum gauge in the system and press on the brake peddle and see if you continue to loose vacuum. You will see some loss when you push on the peddle at first but should build back up as you hold the peddle at one position. If not you have a booster leak.
You could also just unhook the vacuum line to the booster, plug the line and move the car a few feet and see if the noise is gone.
 

CJ-

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Turns out, it’s my 2 piece Macleod clutch.


However, one more question before this thread is killed... on deceleration in 1st and 2nd gear between 2k-3k rpms, is it normal to sometimes hear a faint goose honk sound?

Sounds like Hooooonnnnnnnkkk lol
 

CJ-

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6719F136-060F-4F40-8D0F-75375F8033F7.jpeg EB724B9C-99B7-402C-B307-9F8519A3A701.png B3652D19-4062-42B5-8EF8-0762CE0AA37B.png It took me nearly a year to solve this mystery but here I am with an update.

The vacuum line that mounts to the rear of the supercharger, it leads down the behind the engine about 1 foot downward and connects to the lower section of the intake manifold... the Ford Parts website description is “Emissions Control - Crankcase” and the hose is given a generic name “Connector”.

well mine was rubbing up against the manifold, specifically a protrusion of aluminum on the manifold that has some sharp flashing. It cut through the vacuum hose.

I believe the hose is apart of the Oil Separator system.
 

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