Volkswagen Passat Forum banner

1 - 11 of 11 Posts

·
Registered
Joined
·
124 Posts
Discussion Starter #1
Maybe I am crazy? I started the car last night. It was 25 degF, and the wind was pretty whippy. I started the car, put it in reverse and was backing out of a parking space heading toward a big stone wall when I pressed on the pedal and it went to the floor!! I immediately pulled the emergency brake, pressed the brake pedal a few more times, no resistance what-so ever. I popped the hood, the break reservoir looked ok (you can't really see much since it is tucked under the cover for some unknown reason). I got back in the car, pedal is fine! I am thinking that perhaps I missed the pedal all together? There is a large space under it. Has anyone ever experienced this? I have a 2012 Passat SE sedan with a 2.5. And while I am asking....is there a service manual for the B7 series?
 

·
Registered
Joined
·
124 Posts
Discussion Starter #2
It seemed to happen backing out of the driveway this morning. You wouldn't think it is possible!! No pedal at all, then full pedal?? Then it is fine! I heard the pedal noise, pulled up on the hand brake, 2 seconds later it is fine....this is starting to worry me! No one has had anything like this happen?
 

·
Registered
Joined
·
351 Posts
A problem in the system is causing you to have to build pressure in the system to make the brakes work. Once you have pushed enough fluid into the system, the brakes work until the car is stopped for a while. It could be the seals in the master cylinder or some other part causing the pressure loss. Inspect the system (master cylinder, brake lines, calipers). If you are not seeing any brake fluid leaks or damage, I would start with a master cylinder replacement.
 

·
Registered
Joined
·
124 Posts
Discussion Starter #4
I am leaning toward the master cylinder myself, it just seems strange that there is no pumping it up (like air in the lines), its on the floor then it is not. I will call the dealership as it came with a warranty.
 

·
Registered
Joined
·
4,817 Posts
And while I am asking....is there a service manual for the B7 series?
No Bentley on anything later than a B5 Passat. You can use AllData to access manuals, but these are electronic, IIRC (you'll need the means to store electronic files -jump drive, etc.) which means you'll also be forever reading from a desk top or lap top (no book).
 

·
Registered
Joined
·
124 Posts
Discussion Starter #6 (Edited)
That is fine by me, I have wifi in the garage (much to my surprise!) Thank you so much for this info. I have been researching the "brakes to the floor" issue, seems it does occur (though I am still wondering how as it should be a sealed system, it should have 2 states off the floor or on the floor as long as it is not spongy.) Thios is not the first VW to have a MS issue, my 1980 Rabbit Deisel had one too. The dealership wanted to know which day of the week it was manufactured, it was 225 for a new MS, I ended up going through some brake cykinder kits until I found the correct size. Cost me $ 3.00!
 

·
Registered
Joined
·
4,817 Posts
Ultimately, the MC will need to be swapped out...that is if you can repeat this "pedal sinking" at a later time, preferably while the car is sitting in your yard. :nervous:

Try this: Press brake pedal with ~70-80% of Max force, then scale back to ~40% of Max force, then back to ~70-80% of Max force (all force applications are done without removing your foot from the brake pedal). What typically happens is the pedal drops slightly lower on the second application of ~70-80%, then lower still with each repeated hard/soft/hard force application. I've been able to repeat this sinking pedal "effect" on every MC that had an early failure. In each early failure case, you could brake the car by pumping the pedal...but who wants to be behind the wheel dealing with that!?!?
 

·
Moderate Moderator
Joined
·
16,485 Posts
Doesn't that model have the electric parking brake? Is it possible for that system to malfunction in such a way that it causes this symptom?
 

·
Registered
Joined
·
124 Posts
Discussion Starter #9 (Edited)
I will try that EM, The pedal does feel spongy, when the issue happened it did not pump up, just 2 or 3 times and then it didn't sink at all. Full pedal. I don't know if has an electric parking brake, it doesn't feel like it...or is that normal? I almost have my B5 wagon done, I was hoping that the studded snow tires would just bolt on. They are from ma Jetta.....different hole pattern. Who does that?? LOL
 

·
Registered
Joined
·
124 Posts
Discussion Starter #11
It has not repeated itself. I will do a bleed of the anti lock brake system with the VCDS when the weather warms up. I have been having too much fun driving my B5 around after all the work I did!!
 
1 - 11 of 11 Posts
Top