Occasional Knocking Sound When Braking

[petec]

Sometimes, when braking, I hear a knock sound that seems to come from somewhere near the passenger door. Like something fairly heavy is moving.

For a while, thought that there was something loose in the trunk, but that's not the case.

Anybody have any ideas?

2006 911 Cabriolet

[Loren]

Check the swaybars to see if the mounts are loose. I have seen this happen several times.

[mattieinars]

Hi.

I experienced the same thing on my 996 after having my brake rotors re-surfaced. I replaced the pads and some of the vibration dampers, not ALL, and thats where I went wrong! The sound started after driving for 5 minutes or more and was mostly noticeable when braking lightly or moderately. The knocking sound never occurred under heavy braking so that's what gave me the idea that saving a little money on the vibration dampers was perhaps not a good idea.

To cut a long story short I removed the brakes again and replaced ALL dampers that were not firmly glued to the pads(removed all grease and dirt from the pads backing!). And now I'm not getting these knocking sounds any more :rolleyes:

Hope this helps.

Matti...