Brake Pedal Whooshing Noise

[Limegreen06]

I have just finished going through my braking system on my 04 Jeep tj x (no abs as far as I know). I replaced the drums brakes (wheel cylinders, springs shoes everything) front rotors, pads and calipers. I have adjusted my rear drums to what I think is correctly (slight drag but moves easily), replaced the brake booster check valve, grommet, vacuum hose and I have bled the entire system. I bled the master cylinder (had a helper push the pedal carefully and I opened the brake line closest to the firewall and removed all the air I could see then moved to the further line. we push the break pedal down, not to the floor held it I opened a line then closed it and they let up on the pedal multiple times). I then gravity bled the system starting at the furthest rear and worked my way to the front one wheel at a time. Then two man method bled the system starting at the furthest wheel. I didn't see any air in any of the lines. the pedal felt firm with the jeep off (I had the key turn to accessory to make sure the proportioning valve was on when two man bleeding). and when I turned the vehicle on it feels pretty good but the first third to half of the pedal is soft then it becomes hard but I hear a whooshing noise when I push the brake pedal. I can't tell if it's air in the lines/master or if I have a failing brake booster. I did run a test, I turned the jeep on and let it idle for a bit I then removed the vacuum hose from the check valve and covered it with my thumb. My helper then pushed the brake it was hard (as expected) and there was no noise. this indicated to me the brake booster may have a tear in its diaphragm. Before I buy a new brake booster I'd like to be relatively certain it needs to be replaced.

I appreciate any help and identifying the noise!

I have a link below to a video of the noise if that helps.


View: https://www.youtube.com/shorts/p9OmUzNQDko

 

[TheBoogieman]

There's an expert on the forum to get the correct answer.

 

[any4xx]

It’s not really unusual to hear that while moving the pedal. If you were hearing it while the pedal was depressed and not moving I’d say it’s time for a booster. I’m guessing the brakes FEEL fine? If so, drive and enjoy….

 

[Limegreen06]

It’s not really unusual to hear that while moving the pedal. If you were hearing it while the pedal was depressed and not moving I’d say it’s time for a booster. I’m guessing the brakes FEEL fine? If so, drive and enjoy….

Oh ok I didn’t know that was expected. From the research I have done so far I gathered my brake booster may have been on the way out.

One thing forgot to mention and I apologize for not putting in post originally but even after all the brake bleeding the first third to about have of the pedal throw is softish. I don’t know if that combined with noise leans more towards a bad brake booster or if I’m just not bled the system enough or did a bad job bleeding it.

 

[any4xx]

That sounds more like your master cylinder is bad or just needs to be properly bled.

 

[MikeE024]

I have just finished going through my braking system on my 04 Jeep tj x (no abs as far as I know). I replaced the drums brakes (wheel cylinders, springs shoes everything) front rotors, pads and calipers. I have adjusted my rear drums to what I think is correctly (slight drag but moves easily), replaced the brake booster check valve, grommet, vacuum hose and I have bled the entire system. I bled the master cylinder (had a helper push the pedal carefully and I opened the brake line closest to the firewall and removed all the air I could see then moved to the further line. we push the break pedal down, not to the floor held it I opened a line then closed it and they let up on the pedal multiple times). I then gravity bled the system starting at the furthest rear and worked my way to the front one wheel at a time. Then two man method bled the system starting at the furthest wheel. I didn't see any air in any of the lines. the pedal felt firm with the jeep off (I had the key turn to accessory to make sure the proportioning valve was on when two man bleeding). and when I turned the vehicle on it feels pretty good but the first third to half of the pedal is soft then it becomes hard but I hear a whooshing noise when I push the brake pedal. I can't tell if it's air in the lines/master or if I have a failing brake booster. I did run a test, I turned the jeep on and let it idle for a bit I then removed the vacuum hose from the check valve and covered it with my thumb. My helper then pushed the brake it was hard (as expected) and there was no noise. this indicated to me the brake booster may have a tear in its diaphragm. Before I buy a new brake booster I'd like to be relatively certain it needs to be replaced.

I appreciate any help and identifying the noise!

I have a link below to a video of the noise if that helps.


View: %5BURL%5D%5BURL%5Dhttps://www.youtube.com/shorts/p9OmUzNQDko[/URL][/URL]

When mine sounded like this is was the brake booster.