Vacuum brakes is this normal?

Koshe

Member
Hi guys,

I just converted to a vacuum brake system and I'm wondering if its normal to hear a pressurized air escaping noise when I depress the pedal? :confused:

Edit: The air sound is very similar to that of an old bike tire pump. Like, psssshhhh.

You can only hear it during the travel of the pedal down.

Not on the travel up, or when it'st fully depressed like at a red light.

There is also no air noise while the car is in idle, or in park.
 
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If your car is super quiet you might hear something, but at a stop light steady pressure on the pedal should give no sound at all. If it hisses it's leaking under vac.
 
If your car is super quiet you might hear something, but at a stop light steady pressure on the pedal should give no sound at all. If it hisses it's leaking under vac.

Ok, so I drove the car some more today and realized I gave a terrible description of the noise.

The air sound is very similar to that of an old bike tire pump. Like, psssshhhh.

You can only hear it during the travel of the pedal down.

Not on the travel up, or when it'st fully depressed like at a red light.

Still think it's a booster leak?

Before you go for the rope, have a good look at your vac line to the booster and inspect the check valve

The vac line to the booster looks nice and tight. Sadly, I need to Google where the check valve is. :banghead: brb

Edit: Ok, so I connected the vac line from the booster straight to a vacuum block I got from GBodyParts a while back that has a port made for it. So, If I'm understanding what I'm reading. I don't think I have a check valve?

Edit 2: Nope, misunderstood it the first time. YouTube'd it this time. So it's the valve that goes from the booster to the vac line! Wow, I feel silly.

So that valve is not making any leak sounds when I hit the brakes. I kind of sounds like its riiiiight behind the pedal itself.

I'll get the rope ready... :dead:
 
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Then no it sounds like it's OK. As said before if your car is super quiet you can hear a little bit during travel.

Ok, cool. Thanks to the both of you. I'll monitor the sound just out of habit. If it changes, I'll just take the car in. Now that the wife and I had a baby, I just don't have the time to toy with the car like I used to.
 
It is normal as the booster is drawing air in at the area where the pedal push rod enters the booster. There is a filter in that opening (usually jute, maybe foam), that filters the air (duh) but also supplies noise suppression.

For a faster acting booster can remove filter material.

RemoveBeforeFlight
 
Ok, cool. Thanks to the both of you. I'll monitor the sound just out of habit. If it changes, I'll just take the car in. Now that the wife and I had a baby, I just don't have the time to toy with the car like I used to.

No, that's just normal. As you press the pedal it makes a little air rushing noise -- completely normal. You know you have a vacuum leak if you have a steady hissing or a very hard brake pedal.
 
It is normal as the booster is drawing air in at the area where the pedal push rod enters the booster. There is a filter in that opening (usually jute, maybe foam), that filters the air (duh) but also supplies noise suppression.

For a faster acting booster can remove filter material.

RemoveBeforeFlight
No, that's just normal. As you press the pedal it makes a little air rushing noise -- completely normal. You know you have a vacuum leak if you have a steady hissing or a very hard brake pedal.

What a relief, thanks a lot guys.
 
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