Frount Brake Noise Aud A6 T 2000

[BigRig]

Hello All

I am looking for some help. I have a Audi A6 T on a 2000 plate. I have just changed the front pads. And every think was fine for about 4 week’s. And I have now noticed an clunking noise from the brakes. It sounds like the pads are moving as I put the brakes on. I have fitted genuine Audi pads. Please could you let me know what you think.

Thanks

Pete

[doggy]

Pete,

Did you resolve this issue?
I have the same problem and wondered if you'd had any luck?

Cheers

[lonky]

Do you get a regular thump that is proportional to road speed.

You may also feel this through the pedal.

If so you have a warped disc.

Other possible faults that could give the noise would be
1. faulty ABS sensor, causing the ABS to trigger on that wheel.
2. Wheel bearing starting to go
3. Faulty CV joint - noise evident particularly going round either a left or right hand bend.

However warped disc is most lightly if you have just changed the pads. If you drove hard when bedding them in, the disc can be overheated and will warp.

C

[doggy]

I do get those sort of symptons, but i have swapped both discs and pads on either side at the front and the noise stays on one side. So don't think its the disc being warped

The cv joints have both been recently replaced, noise has started after this.

Is there an easy way of testing the wheel bearing?

Can i disable the abs to test that?

Thanks for your help

[Niall76]

Probably just the pad moving in the carrier. it's common.

[doggy]

can somone recommend a good replacement pad?

don't fancy buying from a dealer

[Niall76]

Try EBC?

[lonky]

To test ABS sensors,
easiest way is with a copy of VAG-com on a laptop and lead.

You can use the shareware version, and a lead from e-bay which will cost about £15

Go into the ABS module
1st read fault codes, if you have a problem with a sensor one may show, however not always as the ECU may not realise there is an issue.

2nd read the measured blocks, you can then see how fast the ECU think each wheel is turning in real time.

Drive in a straight line, if you do not get the same reading from each of the 4 sensors you will have the ABS cutting in when you try to brake.
Naturally round a bend the sensors will read a fractionally different speed as the outer wheels travel further and so faster than the inner wheels.

If in a straight line one sensor is reading slower this is normally because the air gap between the sensor and the inductive (slotted) ring is too large, causing pulses to be missed.


As for makes of brake pads, I would also recommend EBC, as they have a bedding in compound that helps keep the heat out of the disc.

Also new discs can buckle the first time they get hot, as this is when they temper. If in doublt then you need to put a dial guage on them and spin them by hand.

Wheel bearing noise is virtually impossible to check in the very early stages, though over time it will get so that it can be checked by manually rotating the wheel when it is jacked up in the air.

If you do try spinning it with the motor with wheel jacked up in the air, note the following.

1) if car comes of jack it will either damage transmision or drive through a wall.
2) if you spin wheel in any gear above 1st you increase the risk of blowing the differential up. - when you wheelspin the planitory gears spin round the crown at a speed way over the design speed and can explode. I have known people do 70 with one wheel in the air and then wonder why the diff went bang !
3) if wheel is not balanced it can jump the car off the jack !
4) if car is a quattro she would need both front and rear of car off the ground.

[wacky77]

When you replaced the pads did you sand back and recopperslip the sliders and caliper bracket where the pads have to slide to contact the disc?
It could simply be the pads/sliders sticking and clunking free due to a bit of rust/ dirt on these parts.

[Peter D]

Pete,

When you fitted the pads did you ensure the the direction arrow on the inner pad faced the direction of rotation. This may be the cause of the problem I will explain. The inner pad ir retained in the caliper piston by a sprung clip. This clip has a bias on it to ensre the pad rests on the bottom guide. so when brakes are applied the pad is alreadt on the guide. If you fir the pads on the wrong side then a gap appers and when you brake the pad clanks down onto the bottom guide. Regards Peter