Brake Judder

[CraigAdair@191]

Hi All... Had brake Judder on my car, so just naturally changed discs and pads all oem from Mercedes. All seemed ok, now 5 weeks later Judder is back. The car in question is A250 4 matic 39k on clock.... Only seems to happen under light braking. Now this is my 3 Merc and previous cars had no issues with brakes with such low miles. Any ideas. Have been reading online but no one seems to have a definite answer. Lol. Cheers

 

[Droverunner]

A common cause of brake judder a short period after new discs is disc runout due to failure to sufficiently clean the hub surface or possibly a wheel bearing issue, did you prove the new disc was running true with a dti or similar?

 

[brandwooddixon]

If the judder only happens under light breaking then this is indicative of either a disc that wasn't mounted quite flush to the hub (if the hub wasn't cleaned before mounting or even if a part label was left on the disc) or pad material build up in one location (typically caused by hard braking and keeping the brakes applied after coming to a stop).

Its usually good practice to try and bed in new brake discs and pads before performing any hard braking. You can speed this up by putting them through several heat-up cool down cycles through (e.g. braking from 30mph to 5mph half a dozen times, allow to cool then repeat at 40mph and finally 60 to 20mph).

I'd also recommend not leaving the foot brake applied when stationary after a fast stop and if you're not in the habit of braking firmly do that regularly (ever notice how the brakes always appear to work better after an MOT?)

 

[CraigAdair@191]

A common cause of brake judder a short period after new discs is disc runout due to failure to sufficiently clean the hub surface or possibly a wheel bearing issue, did you prove the new disc was running true with a dti or similar?

Nope. Same as any car I had. I use the same mechanic all the time. As before never had issues with any other car. Just this one. Old discs off new ones on.

 

[CraigAdair@191]

If the judder only happens under light breaking then this is indicative of either a disc that wasn't mounted quite flush to the hub (if the hub wasn't cleaned before mounting or even if a part label was left on the disc) or pad material build up in one location (typically caused by hard braking and keeping the brakes applied after coming to a stop).

Its usually good practice to try and bed in new brake discs and pads before performing any hard braking. You can speed this up by putting them through several heat-up cool down cycles through (e.g. braking from 30mph to 5mph half a dozen times, allow to cool then repeat at 40mph and finally 60 to 20mph).

I'd also recommend not leaving the foot brake applied when stationary after a fast stop and if you're not in the habit of braking firmly do that regularly (ever notice how the brakes always appear to work better after an MOT?

 

[CraigAdair@191]

I will try this. Never had issue before with brake Judder on any car. This is my 14th car. Lol. No foot on brake. I always use the hold function on my car at lights etc.

 

[Droverunner]

>>>

did you prove the new disc was running true with a dti or similar?

Nope.

Well this could be a cause of the problem. If the guy didn't prove the discs ran true then it risks this issue. Yes you/he may have got away with it in the past but this time it might not have worked out.

 

[Droverunner]

Ferodo explain it here...

You're in control of brake judder

Brake judder is a common problem that can have a number of causes. Find out the different types of judder, it's causes and solutions.

www.ferodo.co.uk

And Delphi here... note the best practice part way down...

How to prevent brake judder

Brake judder is not necessarily the most technically challenging issue, but it can be a source of headaches for technicians, especially since fitment issues are often at the root cause of it.

www.delphiautoparts.com

 

[EmilysDad]

I will try this. Never had issue before with brake Judder on any car. This is my 14th car. Lol. No foot on brake. I always use the hold function on my car at lights etc.

HOLD uses the normal brake pads to hold the car ... it's just the same keeping your foot on the brake pedal.

 

[CraigAdair@191]

HOLD uses the normal brake pads to hold the car ... it's just the same keeping your foot on the brake pedal.

Lol. Automatic. What else can you do. Lol

 

[EmilysDad]

Lol. Automatic. What else can you do. Lol

Emergency/ hand brake will either use shoes inside the disc/drum at the back or just the rear discs' pads.

Automatic ..... is there another kind?

 

[CraigAdair@191]

Ha ha.

 

[CraigAdair@191]

Emergency/ hand brake will either use shoes inside the disc/drum at the back or just the rear discs' pads.

Automatic ..... is there another kind?

Handbrake. What's that. Havnt had one in yrs

 

[joderest]

just to mention, years ago i had a brake judder on our w163, new discs and pads all round, judder under light braking, ok when really braking hard.
Long story short, one of the rear Callipers pistons was sticky (they are twin piston callipers) so under light braking the non sticking piston pushed the disc over until the other piston started moving, producing the judder. It also warped the new disc.
Fix was to remove and rebuild both rear callipers, new discs again.
Been fine ever since.

 

[CraigAdair@191]

just to mention, years ago i had a brake judder on our w163, new discs and pads all round, judder under light braking, ok when really braking hard.
Long story short, one of the rear Callipers pistons was sticky (they are twin piston callipers) so under light braking the non sticking piston pushed the disc over until the other piston started moving, producing the judder. It also warped the new disc.
Fix was to remove and rebuild both rear callipers, new discs again.
Been fine ever since.

Worth a look. I have 6mths platinum warranty left. So I am gonna ring Mercedes tomorrow. Get them to have a wee look, may as well use the warranty

 

[brandwooddixon]

I always use the parking brake when stationary in traffic or at junctions as it doesn't use the pads to hold the car in position. It should hold the car stationary when idling in drive.
Only on the steepest of roads do I use the foot brake, as well as the parking brake, if I detect that its not holding the car stationary.

 

[CraigAdair@191]

I've always drove using my foot on brake at lights etc since I've started driving 15 odd cars always drove the same. If I needed pads or discs I just had them fitted. never had bother before apart from this car. Just don't buy into this holding on brakes. Yes if your hammering them and they are roasting, but normal driving, just don't buy it. Well that's my thinking. It's going into Mercedes to see the craic.

 

[moosehead]

Had a similar problem with my W203 a few years OK. Mine has the larger Sport Pack twin piston calipers on the front. Turned out to be a sticky piston on the front N/S caliper which then caused the disc to wear unevenly after only a few thousand miles. As another member suggested, I suspect this applied an uneven force to the disc which then caused the wear / warping.

 

[CraigAdair@191]

Yeah. My A250 has the bigger calipers. Took it to Mercedes to see the craic. Their tech said my pads and discs are corroded as they are old. I stated they are only 3 months old and if so they are covered under warranty, no was the answer as the tech said this only happened as my car was parked up thus warranty void......fek that I said they told me his word over mine I informed them I have a tracker fitted and can prove other wise, his word over mine was the response. Then started asking who fitted them. Torque settings etc. I said thought I never drove it and that's the problem. Now I have a feeling they never checked anything else. I told them it's not the end of this. Nobody calls me a liar.... Put it this way. After a few days of me doing a few things. Calls emails and social media. I got a call from head man. Apologize for all. Now car has to go back for new pads discs and a full inspection. Pity it had to go this far.

 

[Botus]

Ford Capri 280's used to get this - it was nothing to do with the brakes

tyres
steering rack
suspension bushes