2012 Jetta TDI brake issue

Brand new 2012 jetta TDI (less than 1,000 miles). Standard, 6 speed.
A few weeks ago, I went to brake, and my pedal went all the way to the floor (no resistance) w/o slowing me down. I let the pedal out (after freaking out a little), and when i went to try again, the brakes kicked in. I was a block from home, so I continued to drive, pulled in to park, and it happened again. Left foot on the clutch, right foot went to brake and went all the way to the floor. Took it straight to the dealer. They checked it, drove it, checked it again. Couldn’t find anything.

I’ve driven about 500 miles since, with no incident. Then, it happened again. My brake pedal literally touched the floor, and didn’t even slow me down. I tried pumping. Nothing. Took the pedal all the way out, and then recompressed- worked fine. Drove it to the dealer, happened one more time on the way (had to pull the ebrake to stop).

They have had it 2 days and still can’t find anything wrong.

I’ve been driving VWs since I got my license. I’ve never even owned an automatic, so the whole “maybe you were pressing the clutch instead of the brake” comment is out of the question. What is going on?!

Report it to NHSTA at the very least. If they get enough complaints they will investigate. I believe you can also see other ones folks have placed in there.

Scary defect.

If you have to pull the brake pedal back up, that pretty much guarantees that it is in the master cylinder. I suspect that the booster is either involved as well or may me getting damaged by the master cylinder leaking brake fluid into it so it might be a good idea for the dealer to change it as well.

according to the dealer- there are no mechanical defects and no fluid is leaking. also no computer error codes registered.

“Report it to NHSTA at the very least. If they get enough complaints they will investigate. I believe you can also see other ones folks have placed in there.”

Yes, and I checked. The only 2012 Jetta complaint I saw was just one air bag complaint.

"Took it straight to the dealer. They checked it, drove it, checked it again. Couldn’t find anything."
I hope you have a copy of a Repair Order from this incident that shows specifically that you complained of NO BRAKES. It should even caution technicians who would be operating the vehicle.

Get documentation from this dealer visit, too, and every time you go. I hope you’re driving one of their vehicles free of charge.

If they can’t come up with anything, I’d want the car grounded until a meeting with the Volkswagen District Service/Parts Representative can be arranged, and I’d want a car to use while waiting and being inconvenienced.


The dealer is wrong and they have to fix it. There used to be a guy named Shelton Harrison who owned a few large dealerships in Tennessee. One of his service managers told a customer that there were no defects in the brakes of a car she had just purchased there. Her heirs successfully sued him out of business.

Most of this is pre internet, but if yo google him now, there are still a couple of articles relating to court documents where the ******** is still trying to wiggle out of debts related to this incident. You dealer might want to look into this before dismissing your problem.

Ok, so NHSTA sent my complaint to their investigation office. VW assigned a case manager to monitor the dealership’s doings with my car.

Oh yeah, the car is still under warranty- you bet I’m driving a loaner free of charge.
I don’t even want my car back until it’s fixed. I live in PA, its deer season, I need to be able to stop on a dime.
I’m just hoping last time they didn’t take me as seriously (24yo girl coming in complaing of some sort of phantom break issue; I got the impression they thought I was crasy, especially when they asked me if i may have just accidently pressed the clutch with my right foot).

I have all documentation, I’m trying to cover all my bases.

Keep you posted on whats going on.

Also check out the VW forums, see if anyone else has this problem. I’d start with vwvortex.

This car is unsafe to drive. They need to start replacing parts like the master cylinder now whether they think they’re defective or not. If they don’t, I’d contact the VW representative listed in your owner’s manual. I’d also consider telling them that you’ll be consulting with your lawyer on what to do if you crash after reporting this issue to them and not having it fixed. You should also start checking into the lemon law in your state.

The dealer called me today and said that they discovered it is the brake master cylinder. There were no details as to how, or why they decided that is the problem, but they are ordering the part and it will be installed next week.

My questions are …

Why didn’t the dealer consider the master cylinder the first time I went in? Within a few hours, the forums erupted in answers to this issue… master cylinder all around.

Does a bad master cylinder usually manifest itself much more seriously, instead of sporadically, and at random? I mean, the brakes didn’t work 4 times, in hundreds of miles, and thousands of braking applications.

Could the slave or booster cylinders also be involved in this issue?

Based on your complaint a master cylinder would be the main suspect. As to why they did or did not do this, that, or the other that’s a bit of a murky area.
One reason is that it would be extremely unusual for a master cylinder on a new VW to act like this.
Two is that any warranty repair must be verifiable. If the dealer throws a part at it and that part is not the problem then the dealer will have to eat the entire cost of both parts and labor.

Without master cylinder in hand and disassembling it I can’t say what is wrong here. You have done the right thing by filing a complaint with the NHTSA and getting corporate VW involved.
I’ve worked for several VW dealers and while the dealers (all car dealers actually) can be a bit shaky my experience with corporate VW is that they are brutally thorough and if there’s a problem they want it solved one way or the other.

From your description of the symptoms the master cylinder was the most logical answer. A new one should resolve the problem. Seems pretty straightforward, not sure why a dealer service dept would send a car back out on the road with brakes that don’t work. It seems you did the right things, contacting VW corp. and NHSTA got someone’s attention.

One need for troubleshooting is for the problem to manifest itself while you are working on it. Intermittent problems are very difficult to find. Brakes however are different that something like,“It didn’t start the first time I turned the key this morning”. Most problems are an inconvenience, brake issues are life threatening. I’m afraid your dealer was just in the wrong mode of thinking at the time.

Master cylinders usually show symptoms consistently, i.e. low pedal, mushy brakes or no brakes. It’s not that their could be an intermittent problem, but that is not a normal failure mode.

As for a slave cylinder being involved, we refer to them as calipers (disc brakes) or wheel cylinders (drum brakes), they are not likely to be the root cause of the problem unless you were loosing a lot of brake fluid. But if something was causing the calipers to retract while going down the road, then you could have the condition you experienced.

If this is the case, I would expect that you would feel a lot of vibration sometime before you put on the brakes. Since the car is new, there is not a lot of room for the calipers to retract. I would expect that something would be wrong in the rear wheels for something like this, possibly with the parking brake. I would also suspect that you left the parking brake partly on to cause this, but I think you would have figured this out by now if that was the case.

Now for the booster, I don’t think that would be the source of the problem, but if the master cylinder leaked any fluid into the booster, then I’d be concerned that the booster would eventually get damaged, but that would only be if you let this problem continue for some time. there is no reason to suspect that it has suffered any damage at this time.