Several weeks ago 'itsthesize' and 'GreatBear' had a conversation in the 'Under the Bonnet' forum about hissing on the driver's side and 'GB' suggested a leaking power brake booster. I'm wondering if I'm having the same problem ..

I have had a similar noise the past several K miles although I would describe it as being like opening a steam valve, blowing off pressure on a pressure cooker, hissing in a way. It's definitely related to releasing the brake pedal. When it first started, it happened after I'd driven awhile .. twenty minutes across town with several stop lights.

I reported this at the first service which was around 9400K. They didn't hear it ... I'm so tired of that ... and suggested that the brake booster always makes a noise. But, couldn't explain why I hadn't heard the noise the first 8K miles.

Now it happens almost all the time. If it is a leaking booster, can't the service people test for that? Am I damaging anything by continuing to drive it this way? (I know that's probably a stupid question) Or worse, am I risking losing braking response altogether?

The car is cool and I love the way it handles, but I also value reliability and good service and we all know those two things are yet to be tested long term ...

Thanks for any advise y'all may have.

 

I have the same problem. How did you resolve this issue.

Thanks!

 

After several trip to MINI maintainence I finally got this problem resolved. At first they couldn't hear it and they said the noise was normal because of the vacuum assist booster. I got very frustrated and finally went on a test drive with one of the mechanic. It is difficult diagnosing an intermittent problem. But I had to be persistant. Finally they replaced the brake booster and I haven't heard the noise any more. I have put about 200 miles on the car since the repair, so I hope this finally resolves the problem. The service order states that they removed and replaced the brake booster, and then reassembled and bled the brakes. This seems to have done the trick. I hope this helps if anyone comes up with this problem in the future. Just for the record, my MC had 49,700 miles on it at the time of the repairs.

 

bump. any new information regarding this problem? my brake pedal has just started making this noise. how much for the parts if you're out of warranty and plan to do the work yourself? is this something a shop would be able to properly diagnose before i spend money on new parts?

 

yes! i have this exact problem after putting about 5,000 miles on my brand new brakes. without a warranty how much should i expect to dish out?

 

I have no idea what the cost would be, since my repair was done under warranty. I can add that I now have 75,000 miles on my car and the problem never reappeared.