Brake pedal vacuum whistle

[ELOV]

Recently I hear what sounds like a vacuum whistle when I take my foot off the brake pedal. It seems to be coming from under the dash. Any thoughts on what it may be?

[howardc64]

Maybe the brake booster seal failure? a common problem on this car. Although I recall mine made sounds while braking. Replacement directions are here

http://www.volvoxc.com/resources/how-to/pdf/power-brake-booster-replacing.pdf

I fiddled around with the bellow and got mine to stop like 40k miles ago. Hasn't been back since. Maybe you will get lucky like me :) Read "Brake Booster Seal" in this link

http://www.freewebs.com/howardsvolvos/brakes.htm

[trw]

I fiddled around with the bellow and got mine to stop like 40k miles ago.

Howard, I assume you did this with booster still installed by somehow contorting your body to get under the dash. Did you completely remove the gray bellows (i.e. slide it off seal) and then reseat it? Re grease seal? Anything you found loose on the black seal at the booster?

[martinperry]

Mine was doing this until recentley
It was the seal on the bellows on the actuator rod, By upending myself into the footwell, I found that the pedal end had slipped forward from the seating groove. Slide the whole thing off, reseat correctley, and hey presto, no more hissing.
For reference, Im 6'4" and 220lb, so if I can get in the footwell, anyone can!!

[ELOV]

sounds like I will be turning pretzel this weekend - thanks guys.

[trw]

sounds like I will be turning pretzel this weekend - thanks guys.

Ditto [thumbup]

[howardc64]

Howard, I assume you did this with booster still installed by somehow contorting your body to get under the dash. Did you completely remove the gray bellows (i.e. slide it off seal) and then reseat it? Re grease seal? Anything you found loose on the black seal at the booster?

Yes, I did not remove the booster. Just slide the driver's seat all the way back and contorted my body down there and pull the bellow off from the booster side and reseated it back on... I didn't reapply any grease. Presto! noise gone in 40k miles so far.

Hope it works for you :)

[OCkids]

Hi, all,
I have got the same whistle from the brake pedal on 2001 XC70 at 125,000 mi today, and I am rather inexperienced as a car mechanic (just changed brake pads, cabin filter, glove box, etc.)
What is 'the bellow' that I am supposed to 'pull off from the booster side'? Is anything holding it? What would tell me that I have reseated it correctly?

[jda2000]

is a grey rubber bellow that hugs the long bolt from the booster that attaches to the brake pedal.

[trw]

It's a round gray rubber 'accordian-like' bellows that seals the linkage between the break pedal and the booster. You need to get under there with a flashlight to see it. What Howard means is to reseat it into a groove on the booster side (firewall side). You can either slide it off or just spin it around to reseat it. If it fails to seal properly and you still get the hissing noise or if the hissing noise is continuous you will need a new brake booster. Time for you to pretzel yourself.

[OCkids]

Thanks, TRW and JDA,
I got in there, reseated it over a soft black plastic on the booster side (is that considered the groove?). Squeaking was gone for 50 miles [thumbup], then it came back (with hot temperature from the engine?), but not as consistently as before.
Another thought: it sounds more like a non-lubed metal rubbing something than a whistle. Did anyone try to lube that area? What grease did you use? I saw Howard asking the same question back in 2009, but I could not find an answer.
Any ideas will be greatly appreciated.

[jiffert]

Looks like I have a similar issue with the booster seal. the black ring that the bellow attaches to has broken away from the booster. basic attempts to reinsert the ring/gasket are not successful. Any thoughts or simple suggestions?

[Astro14]

Thought: you need a new booster. Easy job for a DIY, see resources section...but the booster is expensive...

[Ocean Racer]

Looks like I have a similar issue with the booster seal. the black ring that the bellow attaches to has broken away from the booster. basic attempts to reinsert the ring/gasket are not successful. Any thoughts or simple suggestions?

Bugger, same here.
I have a loose black 1,5" ring hanging on the brake arm.

[reemhcs]

Maybe the brake booster seal failure? a common problem on this car. Although I recall mine made sounds while braking. Replacement directions are here

http://www.volvoxc.com/resources/how-to/pdf/power-brake-booster-replacing.pdf

I fiddled around with the bellow and got mine to stop like 40k miles ago. Hasn't been back since. Maybe you will get lucky like me :) Read "Brake Booster Seal" in this link

http://www.freewebs.com/howardsvolvos/brakes.htm

I just put up a video on Youtube showing the leak was at the firewall of my 2003 Volvo V70. Looks like it SHOULD be an easy fix. I just do not know how. Suggestions anyone?

https://www.youtube.com/watch?v=cBWpakOaVD0