vibration under braking

[david pugsley]

hi I wonder if anyone else has had this problem I've recently had my brakes and brake discs changed not in audi but and over 50mph I have a slight vibration went back to garage and they changed them to brembostill have the problem so went to audi had an inspection to try and find out why audi came back with nothing wrong with suspension amongst other thing that might cause it so them changed them out again and I still have the same problem any ideas thanks dave 

[Steve Gred]

Is the vibration only when you brake?

[Magnet]

Can you feel any pulsing of the brake pedal when you brake relatively quietly David? 
Or, does the vibration occur immediately after you have braked? 
Kind regards,

Gareth. 

[david pugsley]

12 hours ago, Steve Gred said:

Is the vibration only when you brake?

yes only when braking 

[david pugsley]

2 hours ago, Magnet said:

Can you feel any pulsing of the brake pedal when you brake relatively quietly David? 
Or, does the vibration occur immediately after you have braked? 
Kind regards,

Gareth. 

yes very slight only when braking not at any time 

[jammy]

Did the Audi dealer inspect the brake pads & discs or just the suspension?

Sounds like the original garage have not fitted them correctly.

[david pugsley]

2 hours ago, jammy said:

Did the Audi dealer inspect the brake pads & discs or just the suspension?

Sounds like the original garage have not fitted them correctly.

they said they can't inspect the pads and discs as they don't no the tolerances of them but it's my 3 set of discs 

[jammy]

3 minutes ago, david pugsley said:

they said they can't inspect the pads and discs as they don't no the tolerances of them but it's my 3 set of discs 

I’m not sure what you mean by your reply, you need to expand your response more to get the best help.

Why Audi don’t know the tolerances of the pads and discs unless you mean it’s because they aren’t genuine parts?

Are you saying you are on your third set of discs? That is very unusual for such a new model, what year and mileage is your A6?

[Steve Gred]

1 hour ago, david pugsley said:

they said they can't inspect the pads and discs as they don't no the tolerances of them but it's my 3 set of discs 

I Went through 2 sets of discs in 2 years on my a6 c6 3.0tdi as the calipers were sticking and warping the disc from the heat , I replaced my calipers with porche machan 4 pot brembos and what a difference its made. I got hem from VBT , brand new £578 fir the pair with custom braided hoses. 

[Magnet]

Thanks Steve, 

From what we now understand from David, your ‘sticky caliper’ was going to be my suggestion. It wouldn’t surprise me if that maybe the cause, but we need more detailed information from David.

Sorry David, but you are only going to feel any pulsing from the brake pedal when you are actually braking - you obviously aren’t going to feel any pulsing at the pedal when you are not braking. 
Have you tried braking hardener than normal, to test if the vibration is worse immediately after that? 
Kind regards,

Gareth. 
p.s. Take the car on say a 10 mile run and use the brakes more/harder that normal. As soon as you are back home - touch your hand (carefully) on the centre of each wheel to see if any are warmer than the rest. 

[david pugsley]

11 hours ago, Magnet said:

Thanks Steve, 

From what we now understand from David, your ‘sticky caliper’ was going to be my suggestion. It wouldn’t surprise me if that maybe the cause, but we need more detailed information from David.

Sorry David, but you are only going to feel any pulsing from the brake pedal when you are actually braking - you obviously aren’t going to feel any pulsing at the pedal when you are not braking. 
Have you tried braking hardener than normal, to test if the vibration is worse immediately after that? 
Kind regards,

Gareth. 
p.s. Take the car on say a 10 mile run and use the brakes more/harder that normal. As soon as you are back home - touch your hand (carefully) on the centre of each wheel to see if any are warmer than the rest. 

OK great will try that thanks guys

[david pugsley]

16 hours ago, jammy said:

I’m not sure what you mean by your reply, you need to expand your response more to get the best help.

Why Audi don’t know the tolerances of the pads and discs unless you mean it’s because they aren’t genuine parts?

Are you saying you are on your third set of discs? That is very unusual for such a new model, what year and mileage is your A6?

yes sorry there not audi genuine parts padgid first set Brembo next 2 sets I do alot of miles I'm currently on 79000 miles but mostly motorway age of the car 2018 c8 model 

[Magnet]

Thanks David, but that extra information doesn’t lead us any further forward. 
Why continue to change 3 sets of (suspect) brake pads in the hope that the problem is due to defective pads? Apologies, but that doesn’t sound a very logical approach to me. 
Hasn’t anyone thought the more likely cause is ill fitting discs or sticking caliper/s? 
You are yet to fill in the information about the effect of more pronounced braking and possibly greater chance of vibration after that. 
Apologies, but I don’t think I cannot offer any further advice based on what we know/don’t know. 
Kind regards,

Gareth. 

[david pugsley]

16 minutes ago, Magnet said:

Thanks David, but that extra information doesn’t lead us any further forward. 
Why continue to change 3 sets of (suspect) brake pads in the hope that the problem is due to defective pads? Apologies, but that doesn’t sound a very logical approach to me. 
Hasn’t anyone thought the more likely cause is ill fitting discs or sticking caliper/s? 
You are yet to fill in the information about the effect of more pronounced braking and possibly greater chance of vibration after that. 
Apologies, but I don’t think I cannot offer any further advice based on what we know/don’t know. 
Kind regards,

Gareth. 

no I agree but it's just what the garage kept doing but your right I think i will have to go down the caliper sticking route tha ks anyway dave

[Magnet]

Hello David,

I think you are in grave danger of going down the same knee jerk reaction route which has been followed before. Sticking caliper ? Possible suggestion only, and certainly not a probable. 
No feed n

back yet on the questions I asked, but if it were mine, I would first be checking the fitting on the discs to ensure the mating surfaces of hub to disc are scrupulously clean and free from rust and that the discs are rotating true, within acceptable limits. 
Your call, but you can continue to throw parts at it in the hope it will go away. As yet, you haven’t convinced me ( although I might have missed something) that the problem is indeed due to some issue with the braking system. 
Kind regards,

Gareth. 

[jammy]

2 hours ago, Magnet said:

Hello David,

I think you are in grave danger of going down the same knee jerk reaction route which has been followed before. Sticking caliper ? Possible suggestion only, and certainly not a probable. 
No feed n

back yet on the questions I asked, but if it were mine, I would first be checking the fitting on the discs to ensure the mating surfaces of hub to disc are scrupulously clean and free from rust and that the discs are rotating true, within acceptable limits. 
Your call, but you can continue to throw parts at it in the hope it will go away. As yet, you haven’t convinced me ( although I might have missed something) that the problem is indeed due to some issue with the braking system. 
Kind regards,

Gareth. 

As Magnet has said, don’t throw good money after bad.

logically, if the problem wasn’t there before the brakes were changed, and Audi have checked the suspension, it points to an issue with the fitting by the original garage.

[david pugsley]

4 hours ago, jammy said:

As Magnet has said, don’t throw good money after bad.

logically, if the problem wasn’t there before the brakes were changed, and Audi have checked the suspension, it points to an issue with the fitting by the original garage.

OK great I'm going to first check that one of the calipers are not sticking then I will check if there fitted properly thanks anyway guys 

[Magnet]

OK David, but I’m not sure why you are not answering the question I asked and letting us know about the test I suggested. Anyway….

How are you going to test each caliper by the way? 

Kind regards,

Gareth. 

[david pugsley]

14 hours ago, Magnet said:

OK David, but I’m not sure why you are not answering the question I asked and letting us know about the test I suggested. Anyway….

How are you going to test each caliper by the way? 

Kind regards,

Gareth. 

Gareth sorry but I thought the test was drive 10 miles braking heavy then see if 1 caliper was hotter than the rest I can't get into the garage for them to check if there fitted properly for another week thanks dave 

[Magnet]

Yes David, so have you done that? An have you checked if the vibration is worse after moderate braking - or not? 
Kind regards,

Gareth. 

[david pugsley]

1 hour ago, Magnet said:

Yes David, so have you done that? An have you checked if the vibration is worse after moderate braking - or not? 
Kind regards,

Gareth. 

yes I've done the test and no o the calipers felt any different and as for the breaking its the same all the time but only can feel it when break 50 mph and above so tomorrow morning I'm going to take the wheels off and see if I can see anything ie if there seating properly thanks dave