Hello All,

Before I start my story, let me introduce myself. I am a proud owner of two fantastic Astons: V8V coupe (MY 2008) and DBS volante (MY 2011). The second one, after long months of hunting was bought last year. As I love the brand and the cars I have been trying to keep my cars in an excellent condition, so both of them are covered by the extended AM warranty. Since the V8V gives me a lot of fun, I started worrying about the DBS.

The DBS lost its confidence during braking:

1. Low speed braking (below 20Mph): I feel like the bakes pulse. The brakes repeatedly changes their braking force (like someone pushes the car repeatedly)

2. High speed: during braking I feel steering wheel vibration and shudder

I ask my local AM official dealer for help, however after two days in the workshop the problem still exists. In the meantime I did the following:

1. All alloy wheels have been examined and checked

2. I have changed all tires to new Pirelli and recently to new Michelin

3. All carbon ceramic rotors and pads have been checked and cleaned, it seems all are fine (as per AM specialist’ statement)

4. All wheels have been optimized by Hunter


I also did a brake force independent diagnostics, which confirms the braking force variations, however the force changes for all wheels, so there is no particular wheel suspected. It seems all wheels pulse the same way as per the diagnostics below.





As I read horrible stories on CCM brakes where at the end of the day new rotors cured all vibrations, I wonder if it could be my case. However, the brake diagnostics show that the braking pulses come from all wheels at the same time.
I have not noticed any ABS malfunction, so the question is if one faulty ccm rotor could have an impact on all four calipers to pulse (I cannot imagine I have all rotors faulty)?
BTW, my AM dealer confirmed the rotors and pads looks perfect, it seems they are well bedded-in.

I would appreciate any suggestion as I am completely lost here. The brake pulses suggest the surface on rotors or/and pads is not perfect, however I could not explain why all wheels have the identical pulses at the same time.

 

Worn steering and or suspension components? A shudder at either side of the the front would affect the other side and probably the rear simultaneously (at least I think it would).

Or an issue with the assist system? Not sure whether the assist is vacuum or other.

 

Thank you Mike. Hmm, it seems steering and suspension is fine. My AM dealer did steering alignment and checked the suspension before they granted new extended warranty. They did not report any issues. They also changed brake fluid during regular maintenance. I suspected an air in the brake pipes as I feel the brake pedal shudder as well. My dealer said air is not possible as they pumped a new fluid up.
I have never heard of the assist system. What does is do while slow speed braking?

 

To my shock recently I found out you cannot clean the ceramic brakes with any kind of agent and even tire shine over spray can destroy them! That should be hammered in by the Aston sales agents when buying these cars with carbon's (I have a V12S)... maybe that's the problem? Your 2008 V8 - good for you still have the extended warranty which I also do for piece of mind, however, cleaning agent on carbon brakes are not a warranty problem - just a carbon brake problem. You can extend an Aston warranty 12 years - what do you think you will do after the extensions run out? I'm actually thinking possibly getting an old Vantage as a daily driver and the V12S as the occasional car, like the DBS of yours.

 

I'd have to know more about how the force is monitored in the plot that you showed above. Are they using some kind of line pressure sensor at each caliper? Do you know where and how this measurement is taken? It might still be one brake rotor with a problem. In a hydraulic system where all the lines share a reservoir, a disruption in one leg of the line will effect them all and it might look like they are all experiencing the problem. This depends on what data is measured.

Your symptoms sure sound like a brake rotor or wheel issue.

 

Yes, I have never used any aggressive cleaners near my wheels. I use soap and water only applied on a wiper, so I do not assume my ccm rotors are chemically impacted. Regarding my V8V, I decided to sell it within next year. I just cannot use Aston without warranty. I will have a bigger question when my DBS turns 12 years. For sure I will not sell it.

 

[QUOTE=blue2000s;4712425]I'd have to know more about how the force is monitored in the plot that you showed above. Are they using some kind of line pressure sensor at each caliper? Do you know where and how this measurement is taken? It might still be one brake rotor with a problem. In a hydraulic system where all the lines share a reservoir, a disruption in one leg of the line will effect them all and it might look like they are all experiencing the problem. This depends on what data is measured.

They used a diagnostic tool called "Plate diagnostic line HEKA". There are 4 barking paths measuring constantly braking force on each wheel. You need to drive and brake thru the plates. More about the tool:

 

Cool product. I think you may still have a rotor issue.

 

That's the same thing [probably not same/exact/brand/etc] they've always had in the NJ Inspection stations to check brake performance. I think that's one of the few tests to survive, plug in diagnostics, and brakes, then up to get your sticker.

 

Hey there, having the same kind of issue with the brakes at high speed when slowing down I feel some kind of vibration.I just had the wheels balanced. My brake pads were replaced 4000 miles ago. I am not the original owner. I am very gentle on my brakes. I was thinking maybe I need to start stopping or stopping more aggressively to hopefully get the issue resolved. Not sure if that’s cure. Did you ever resolve the problem? Solution?

 

Sorry to read about your issue. After I have exhausted all options and ideas, I decided to replace rotors and pads at the front. Shockingly pocket painful exercise, however the vibrations were gone immediately. It appeared the surface of rotors had different friction due to aggressive wheel cleaners used, so the vibrations came from uneven brake force applied in different parts of the rotors. Since then the car brakes brilliantly and no one is allowed to clean my wheels. I do it personally once a year, when the wheels are off the car after each season. Do you how many pads sets were used with your existing rotors? Perhaps your rotors are worn and need replacement? AM recommends to change the CCM rotors after 3 pads sets.

 

I learned early on with the V12S - if you have Carbon brakes do not use any chemicals to clean your wheels - I wish the Aston Dealers and the owners manuals really pressed this critical issue to owners.

 

Thanks for the quick reply. The car only has 19,000 miles. The brake pads were replaced at 15,000. When the car was inspected everything looks fine. I’m pretty gentle on the brakes so I haven’t use them aggressively. I was thinking maybe if I start using them more aggressively back to back for some time things may smooth out. I have never owned a car with carbon ceramic brakes so I wasn’t sure if this was somewhat of a normal behavior for a short period of time. Casual local driving no issue whatsoever. It’s only at high speed ,say around 80mph slowing down.

 

Prefurbia is absolutely correct. Do not use any chemicals on Carbon Ceramic..
My 2012 V12 Vantage had 54000 miles on original pads and rotors....no issue except for the squeak....only 50% worn.
My 2019 DBS is just as good although it appears they have also resolved the squeak issues.
Owners manual says not to use chemicals...people should read it.
Thanks,
JH

 

I agree. I do not use any chemicals on my vehicle except soap. The issue was noticed after purchase. Do you think by being aggressive on the brake repeatedly on a drive from high speed will somehow smooth out the pads after a period of time?