A45 Font discs and pads

[Revo]

hi all can any one please help with some advice my A45 went to a MB dealership with a brake judder only at high speed and when braking, I thought from the back because no judder through the steering wheel they said front right replaced discs and pads the car had only done 9500 milesat 3 years old, 700mile later judder back they replaced second set. 1000 miles now later its back again they've now changed front tyres but made no difference I don't think they know what they are doing PLEASE HELP with any advice.

 

[tonysmb]

Have you had from new? When they replaced the discs/pads each time, did it cure the problem initially and did you bed the pads in? To be fair, many people don't but if you brake hard, using much of the braking capability, it's possible to get the discs very hot and if the driver then holds the brakes on whilst stationary, warp the disc(s) . Do you 'track' it?, any modifications to wheels, brakes, wheel-spacers, suspension etc that might affect things? Wheel nuts torqued properly?

It seems odd that you've had three (original plus two (or is it three) further sets) sets of discs/pads that have, after a short mileage, exhibited the same symptoms as that wound tend to rule out faulty parts, assuming that they're all genuine parts. What did the dealer think it was originally, warped discs?

 

[Revo]

Have you had from new? When they replaced the discs/pads each time, did it cure the problem initially and did you bed the pads in? To be fair, many people don't but if you brake hard, using much of the braking capability, it's possible to get the discs very hot and if the driver then holds the brakes on whilst stationary, warp the disc(s) . Do you 'track' it?, any modifications to wheels, brakes, wheel-spacers, suspension etc that might affect things? Wheel nuts torqued properly?

It seems odd that you've had three (original plus two (or is it three) further sets) sets of discs/pads that have, after a short mileage, exhibited the same symptoms as that wound tend to rule out faulty parts, assuming that they're all genuine parts. What did the dealer think it was originally, warped discs?

morning thanks for your reply
car had done 2750miles year old when I got it a very slight judder through the body of car at this point just though 4 wheel drive trying to do something when braking. it got worse just before warranty up at 3 years old 9500 miles and so put in the dealership to have checked out there verdict was not covered by warranty front right disc warp, 700miles later came back second set( just to say I live in Norfolk with not many fast roads that allow 70mph braking so not something I can check every day)
Never tracked absolutely standard I never had wheels off slight damage to front rim the dealership just don't know what's wrong can the hub that the disc sit on be warped which in time make the disc warp I think its marginally worse when suspension in AMG sport mode???

 

[st13phil]

I don't think they know what they are doing

Sounds like a fair analysis of the situation.

As @tonysmb says, the fact that the problem has existed across three sets of discs and pads would tend to rule that out as a cause, but the curious thing is that each time they’ve been changed the problem goes away for a few hundred miles before reoccurring.

My only suggestion would be to engage directly with MB Customer Service at Milton-Keynes and ask them to support the dealer in achieving a proper resolution.

 

[tonysmb]

It could he any number of things, unfortunately. It sounds as if it, or a driveline vibration, might have been present to a degree since you bought it, is that correct? The fact that new discs/pads seems to cure it for a while, though, is odd.

Damaged front wheel? - how bad? That could point to an out-of-true wheel, but doesn't explain why it's okay initially, likewise if one or more tyres had flat spots, or internal structural damage.
It's almost impossible to suggest the cause of the problem, without somebody driving it or physically checking it, ie suspension damage when the wheel was damaged, faulty brake-assistance/stability system being partially activated, faulty/loose driveshaft/diff., cracked spring etc..

Did the dealer carry out a Star diagnostics check, possibly not for a perceived brake disc problem. It won't highlight mechanical faults as such but might show up electronic faults, ie brake/stability systems.

Did the dealer drive it in order to replicate the problem, or just replace the discs each time?

Any unusual tyre tread wear patterns?

As already suggested, MB customer service worth a try but a potential difficulty is that as you haven't owned the car from new you can't be sure of its history prior to purchase and if it's found to be a non-warranty issue, it could rack up time at dealer rates. A good indie is an option if MB customer services aren't forthcoming but the downside is warranty/goodwill. Catch 22.

Has a run-out check been done on the discs, and also done as soon as the new discs were fitted? I'm not sure how the hub could be out of true and I'd be surprised if 3 sets of discs have been fitted without the mating surfaces being clean/clear.

I presume that the A45 has electronically controlled dampers, if it's worse in Sport mode, faulty damper?

Sorry, no answers but the 'temporary' cure is puzzling and could point to something suspension/driveshaft-wise being slightly out of true which gradually affects the disc once it's put to use, but that's pure speculation, and doesn't seem to make sense.

Please keep us updated.

 

[Revo]

It could he any number of things, unfortunately. It sounds as if it, or a driveline vibration, might have been present to a degree since you bought it, is that correct? The fact that new discs/pads seems to cure it for a while, though, is odd.

Damaged front wheel? - how bad? That could point to an out-of-true wheel, but doesn't explain why it's okay initially, likewise if one or more tyres had flat spots, or internal structural damage.
It's almost impossible to suggest the cause of the problem, without somebody driving it or physically checking it, ie suspension damage when the wheel was damaged, faulty brake-assistance/stability system being partially activated, faulty/loose driveshaft/diff., cracked spring etc..

Did the dealer carry out a Star diagnostics check, possibly not for a perceived brake disc problem. It won't highlight mechanical faults as such but might show up electronic faults, ie brake/stability systems.

Did the dealer drive it in order to replicate the problem, or just replace the discs each time?

Any unusual tyre tread wear patterns?

As already suggested, MB customer service worth a try but a potential difficulty is that as you haven't owned the car from new you can't be sure of its history prior to purchase and if it's found to be a non-warranty issue, it could rack up time at dealer rates. A good indie is an option if MB customer services aren't forthcoming but the downside is warranty/goodwill. Catch 22.

Has a run-out check been done on the discs, and also done as soon as the new discs were fitted? I'm not sure how the hub could be out of true and I'd be surprised if 3 sets of discs have been fitted without the mating surfaces being clean/clear.

I presume that the A45 has electronically controlled dampers, if it's worse in Sport mode, faulty damper?

Sorry, no answers but the 'temporary' cure is puzzling and could point to something suspension/driveshaft-wise being slightly out of true which gradually affects the disc once it's put to use, but that's pure speculation, and doesn't seem to make sense.

Please keep us updated.

Really appreciate your time and possible courses will keep you in formed

 

[merc estate]

Check discs with manufacturer, they may have been recalled faulty and the shop has not changed them, i had that with Jaguar discs.

 

[Muckypaps]

Achieving 70mph is possible on most roads with an A45, it's how hard you stamp on the brakes that will cook the discs, especially new and not bedded in.