C3 Brake Judder after New Discs / Pads - twice!

[noumenon]

Hi folks,

We have a 2008 Citroen C3 1.4 16v. When we bought it, it had a brake judder, the dealer fitted new discs and pads which seemed to cure it. A week later, the judder was back and so the dealer replaced one front disc. Again this seemed to cure it. But now it's back!

Interestingly the first time it happened, you could feel it through the pedal. The second time you could only hear it (but could feel it in the passenger footwell). This time, it's only just developed, so can only be heard. It is consistent with speed (faster knock at speed) and is not related to gear (clutch in/out makes no difference).

Two independent mechanics have had a look at the suspension parts etc. and can't find anything. At this point, I'm out of ideas (though naturally it'll be going back to the dealer again). Any thoughts on what we should look at or try?

Many thanks. =)

[drdino]

Do they clean the hubs before they fit the new discs?

[noumenon]

Yes they claim so. Although if there was a misalignment, wouldn't it show up as immediate judder, rather than develop over time?

[megamaniac]

I did a Saxo years ago and in the end I discovered the hub flanges were no longer true. Apparently it had sat with no driveshaftts in for 6 weeks waiting for a gearbox repair.

[noumenon]

Thanks. The two things that are strange is that :
(a) it's taken time to develop both times the discs/pads were replaced
(b) we've just discovered that it's almost not noticeable on a cold/wet day and very noticeable on a hot day once some heat is in the brakes.

[Dave Brand]

What pads did they use? I'd expect a Citroen dealer to fit OE pads, but they may have used cheap aftermarket products to save a few quid.

[noumenon]

Undoubtedly cheap pads. I haven't pulled them apart so no idea what they are.

Today it seems to come and go, but it seems to be at a particular strength of braking (if that makes sense). So break lightly, no noise, brake moderately, noise, brake hard, no noise. Could that be pads?

[Dave Brand]

It does sound pad-related; if you can see the calipers through a gap in the wheels you may be able to read the manufacturer's name on the back of the pads.

[noumenon]

Alas the alloys are multispoke so I can't see a thing through them. The judder/noise has now completely gone. Today I have a metal to metal noise, but this could just be the pads. I guess wait and see what happens...!