Front end rumble when braking

[Wacko74]

Hi all

Got back from holiday yesterday and I noticed driving back from the airport that when I applied the brakes there was a rumbling or juddering from the front end
It’s almost like driving over the rumble strips they paint on the road
Cars a ML W164
Any ideas guys

 

[Benz17]

At low or high speed. Could be warped brake disks.

 

[whitenemesis]

Car parked up for a significant time? Possible rust deposits on the discs, should clear quite quickly. Otherwise could be pad deposits on the disc which can be more tenacious. Try a few hard high speed stops (70mph to 10mph) and see if it helps.
In daily driving it's very unlikely to be warped discs, especially if it only appeared after parking up...

 

[Wacko74]

i first noticed it coming off a slip road so slowing from 70ish
I wondered about rusty disks even though it was on the multi-storey it’s been damp for a couple of weeks
Wasn’t brave enough for the heavy breaking test

 

[sgregory124]

i first noticed it coming off a slip road so slowing from 70ish
I wondered about rusty disks even though it was on the multi-storey it’s been damp for a couple of weeks
Wasn’t brave enough for the heavy breaking test

As has been said above, almost certainly a build up of deposits on your pads. I had exactly the same issue on my car for a few weeks after I picked it up, the heavy braking technique works but you have to reasonable number of stops to make it totally effective. I did 5 heavy 'slow downs' from 60-30mph and 5 80-0mph stops, enough to get the brake discs 'popping' (i.e audibly contracting on cool down). Between each, drive at a regular speed to give everything a chance to cool down.

It goes without saying, do it on a deserted road if you can and also, do not under any circumstances sit with your foot on the brake at a standstill after one of those stops for more than a few seconds, otherwise you'll have other problems.

The technique worked for me and the problem has never returned (same discs and pads up front since I did the above).