Getting a knocking/clunking under braking...

[Jim]

Occasionally when my I brake when my car is cold I hear a knocking/clunking noise from somewhere underneath the car. It only happens for the first couple of times I use the brakes when the car is cold and then it appears to stop. I recently had a rear brake pipe replaced by a garage for my MOT and it has only been happening since this has been done.

Anyone any idea what is it?

 

[K10Daz]

Could be a warped disk mate, can you feel the pedal try and push back up? is it severe braking or is it light braking? Id go for new disks and pads, plus with the colder winter setting in id get them sorted out anyway buddy

Daz

 

[paul_k10_Lx]

i know this is a stupid answer but look under neath and check they havent left a pipe clam on ive seen this in a garage before scared the hell out of me to think somone would do that

 

[Jim]

Could be a warped disk mate, can you feel the pedal try and push back up? is it severe braking or is it light braking? Id go for new disks and pads, plus with the colder winter setting in id get them sorted out anyway buddy

No I can't feel the pedal trying to push back and when it does happen, it can happen under any sort of braking, light or severe.

About the brake clam paul, what am I looking for? Also, wouldn't that cause it to knock every time I brake rather then just the first couple of times?

Thanks for the responses..

 

[paul_k10_Lx]

ahh yeah didnt see that one does it come from the front or rear?
might be that ur drums need adjusting up (rubbing when cold)

 

[SammoHung]

I think "clam" is meant to be "clamp" a tool for temporarily nipping closed the flexible hoses?

Here’s another thought...mine does this from time to time (rarely):
The front brakes have a semi circular metal stone guard that is very close to the rotating brake disk. This guard corrodes and can bend if a stone hits it. If it gets too close to the rotating disk it can rub. The rubbing noise goes on and off during braking and steering accelerating etc. could this be it?

Though I wouldn’t describe this a knocking, more of a loud scraping.

 

[Arnold]

I have a slight knocking but thats because the backbox keeps slipping off one of its mounts, and the exhaust pipe bangs against the rear axle under braking

Just a thought!