Air pressure sound in brakes

[TheRedBull]

Noticed more an air pressure sound in my brakes. Although, the rotors and the calipers were replaced at home with my older nephew who's more advanced XJ guy. And the brake fluid is good. My only concern is that when bled the brakes, just may have not done enough times. Seemed fine when we test drove everything upon completion.
I will post a YouTube video like I recorded of the air sounding brake pressure.
Not sure where to go from here on the brakes. [they ride fine tho]
** Can't post pictures cuz I'm meeting the quota of max file size [or even less!] and it still wont let me upload! [its jpg] Uploader is kinda crapy! - sorry.

http://www.youtube.com/watch?v=YUSRQPhjMOs&fmt=18

[cantab27]

sorry mate i have no idea , but just wanted to say that is a great way to post ya question:thumbsup::thumbsup: some one will be along to sort it out for ya .....:happy0180:

[pingpong]

MIGHT be the brake booster going bad. Have you checked all your vacumm lines, especially the one going to the brake booster?

[default83]

sounds like the booster to me as well.

[Mudderoy]

I didn't want to post this last night and give you false hope that you had an answer...

Everyone should take a lesson on how this question was asked. With so many of us having cell phones with cameras, and video/audio capturing capabilities this helps us ALL not only better understand the problem but allows us to learn the sites and sounds of it.

Great idea! :patriot:

[4.3LXJ]

This is the sound of vacuum in the brake booster. It is just getting worn. The diaphragm is probably still good or you would get the sound at full pedal. I would just watch it and replace it if the situation gets worse.

[TheRedBull]

Thank you every last one of you. As issue is not assured yet, majority rules 'brake booster' going bad ?! ..I will try to learn more about what that is exactly and see how much to replace it.

[4.3LXJ]

It is that big black round thingy between the brake master cylinder and the firewall.

[xj4life2]

You should also make sure the check valve on the booster is good prior to replaceing the booster a bad valve can cause that same thing, but more than likely Steve is right and the booster is bad. But I always try the simple things first. Also props on the post !! that makes it so much easier to figure out issues. Nice job

[TheRedBull]

Thank you! will do some checking. gracias!

[pingpong]

If you go to replace it... do the brake booster upgrade.. I cant what yr or model to use, but with a few mods you can get a dual diaphram one.. and have way more braking power

[afbond03]

Thanks for posting this up. I have been having this issue to and with your video seems we have the same problem, good to know what the fix probably is.