Brake failure on new 2015 Q5 (534 miles on)!
 

Almost caused collision! Would appreciate your suggestions. The dealership said they found nothing wrong with the car :-( Here was what happened.

I approached a downhill intersection and my new Q5 failed to stop at the Stop sign. Prior to arriving at the intersection, I drove at a very low speed (5-10 mph) as I was in a residential area where I wasn't familiar with. I gradually stepped on the brake however the Q5 was still sliding. The brake was locked up/hardened as I applied more pressure and the anti-lock brake did not kick in (no pulsating motion). My car continued to skid down through the intersection and almost hit the car crossing. It failed to come to a complete stop so I had to steer it past the intersection after which I continued at a low speed and stepped on the brake a multiple times trying to regain control.

The hill wasn't too steep. The road was only slightly wet (the weather was very mild, in the 50F-60F.) The car had always been parked in underground garages at work and at home. I was shocked and extremely disappointed at how a new vehicle purchased just a bit over a month ago and driven only 534 miles could have caused such major failure.

Do you have any suggestions? Would you take the car back or if not, what choices do I have (I purchased it second week of Dec so this is about 6 weeks post sale). Thank you for your reply!

You say you skidded, so it sounds like a traction issue and not a brake issue.
Perhaps there was some issue with the road surface at that intersection or something coating your tires at the time?

What tires do you have?

Can you replicate the issue? I can imagine it must be terrible to feel that your brakes might let you down at any moment. The best thing to do is to take it straight to the dealer fora thorough check. Steve

Like JaXen mentioned, sounds like there was an issue with the road. Was it freshly paved with asphalt? Fresh asphalt with a bit of rain can make for a very slick surface. Something similar happened to me in my first A6 with quattro: I was making a low speed u-turn, newly-paved road, drizzling rain. The car went sideways and kept doing so until I throttled out a bit.

Brake failure is very serious and a fault in the system would show up in the diagnostics or physical inspection.

Sounds more like a slick surface + new tires.

Did it jerk at all? Read my scenario:

https://www.audiworld.com/forums/q5-...2862187/page2/

Did you pump the brakes? Depending on the condition you can get what's called ice pedal, sounds like that happened (if the pedal went rock hard). Pump the brakes and that will restore braking.

Quickly buy a $5M personal liability policy.....
 

I'm not joking here, a relative recently tapped a J-walker and the lawsuit against him can go that far, car insurance only covers medical, pain and suffering are on your own. It opened my eyes and you can get a $1M liability umbrella isurance policy for about $200-300, that's chump change compared what someone can take you for(car(s), house, savings, garnish future wages, etc).

How can you possibly drive that car with a warm fuzzy feeling without knowing what exactly happened. I would contact Audi headquarters, tell them what happened and ask them to have a "braking engineer" converse with you to determine exactly what happened. Tell them that someone could get killed, that will make them listen. Get a case number on this so you can throw this back into Audi's face if you have an accident. I would demand another car if Audi Corp. doesn't respond on the likely cause. You may need a lawyer at that point.

Now if the car is fine, as others stated you most likely slid due to new tires (Audi states in the manual they are slippery until worn in). and a slick road surface. Was the road surface mico-paved/sealed recently? We had a section of road around here that was micro-sealed and had a ton a of accidents when wet. The state said it met specs and couldn't find anything wrong, but the accidents continued, the state repaved with micro-seal and the accidents all went away.

Also if all four wheels are locked in braking, the ABS (pulsations) won't be there.

Good luck!

Sorry to hear this story, but lot's of things you state make no sense at all.
Going 5-10 mph, brakes were locked, skided through the intersection, warm temp, minor hill, & slightly wet.

With ABS you will not necessarily feel pulsation in the brake pedal. Did you release the brakes to steer? If so why? With ABS you steer while the brake are applied.

Take it out on a nice big open parkig lot. I call it Brake testing.
Start out at slow speed - 5 mph and apply the brakes. Keep brakes applied until it stops. you really should not travel more than about 5-10 feet at this slow spped.
Do this again at 10 mph.
Do this again at 5 & 10 mph and try steering with brakes applied. Keep them appled do not release the brake pedal. You should be able to easily steer the vehicle.
Repeat until you feel confident the brakes are working and you understand how ABS & steering work.

X2

Can the OP chime back in and answer a few of the questions posed by the various members. As we all drive Q5's we would like to know if this is a one off or if there is indeed a potential issue.

While I would tend to think that this was a road condition / traction issue, I don't want to discount the OP's experience and sweep this under the rug. Anything is possible these days.