with a passion

problem with the rear brake job?

Another happy owner...passionate about his Audi.

Pierreb, curious to know why?

stay tuned. i don't know how much i broke it yet....

stay tuned. i don't know how much i broke it yet....

Please share.

i have some pics to grab off the camera, so i'll do that tomorrow.

Pierreb;
There is a post where someone had an A6 involved in a head on, perhaps if the car is totaled you might be able to get a used e brake at a cheap price.

hey it's not quite that bad, but thanks :)

I'll post an update soon with some pics.

let me recite my tale of woe:

during my last LOF (81,000miles...yikes!) quoted $580 from the dealer to replace rear worn pads, says the rotors are fine but the pads are really low (down to 2mm). needless to say i'm a little taken aback, as I figure the pads can't be more than $100, tops.

so off to audipartsdepot I go, looking for the actual price. meantime, I had purchased the bentley manual (on DVD) and perused the procedure. also had recent testimonials below to go by and figured this one was within my abilities...

so Saturday comes and my rear pad order arrives (thanks Carson!) :
http://img7.imageshack.us/img7/7677/dsc2302.jpg

take the wheel off, and proceed to the vag-com portion, which is essentially:

- Open PB controller under Chassis/53
- Basic setting
- type in '10' for the diag cycle and click 'done'.

at which point, you hear the parking brake doing its thing as it checks everything is ok. no error codes? good! onwards:

- Open PB controller again
- Basic setting
- type in '7' to 'open parking brake'.

noise/whirring some more and I notice the right side (passenger) quits while the left keeps going...uh oh. then a 'beep' on the DIS (dashboard) with a yellow 'P' and a circle with a line through it...uh oh x 2....

Fault logged: Basic Setting failed execution, or words to that effect. DTC 1087, iirc.

Succumbing to my stupidity and curiosity, I decide to forge ahead and at least try the next steps which involve:

1. removing the caliper

http://www.audiworld.com/tech/pics/wheel139-wrench_socket.jpg
(pic stolen from A4 brakes tech article. 13mm socket wrench, 15mm open wrench)

2. here is the right one removed

http://img11.imageshack.us/img11/1370/dsc2296.jpg

on the left is the brake line, on the right and attaching to the parking brake actuator (motor+gearing) is the electrical connection back to the car. I chose not to disconnect it during this work as it wasn't really bothering me.

3. close-up of the very worn pads

http://img10.imageshack.us/img10/2010/dsc2297r.jpg

4. old next to new

http://img4.imageshack.us/img4/316/dsc2298.jpg

5. and finally new on rotor

http://img4.imageshack.us/img4/9295/dsc2303.jpg

At this point I'm feeling pretty good about myself, and turn my attention to the piston I'm allegedly supposed to be able to push back by hand(those are the word for word instructions in bentley, btw).

One small problem.

The piston won't budge.

At all.

I remember reading ct-audi-A6-3.2's thread (http://forums.audiworld.com/showthread.php?p=23740537#post23740537), but I can't get the torx bolts to move. So I do the smart thing and put the old pads back on, remount the caliper and...

Try the other side.

I can hear you saying 'NOooooooooo!' right now, really I can.

Take the wheel off, take the caliper off, try to push the piston in...no joy.

This is the point where you should stop unless you have a) the means and ability to do a brake fluid change and b) the means and ability to rebuild a caliper.

(I of course, did not stop and dug my grave in further. Read on!)

Back to ct-audi's thread I go, cos I remember him saying he had to rebuild the piston and there's a 'trick' to manually retract the piston. I match the section in Bentley to what he was saying and proceeded to remove the actuator with a torx tip fitted to my socket wrench:

http://img13.imageshack.us/img13/970/dsc2304.jpg
(the socket at the center fits a Torx 40 tip)

actuator

http://img16.imageshack.us/img16/2110/dsc2305.jpg

Instructions say to turn the pressure nut via the center torx bolt clockwise until you hit the stop, then push the piston in by hand. I note with some despair that the pictures in bentley don't show the brake line connected...

and now for the facepalm moment:

during my fiddling I probably turned counter-clockwise and the piston came out even further!! Major uh oh, as now I couldn't even put the caliper back over the old pads, nevermind the new ones!

Long story short: had to be able to at least get the car towed, and that meant putting the caliper back on without the pads and saying a little prayer for my rotor. Unfortunately, I managed to pump the pedal just enough while putting the car in reverse/neutral to maneuver it out of the garage for the flatbed, that I popped the piston and the car bled accusingly in front of me.

car's now at the dealer where both calipers are getting rebuilt (something that most likely would have needed to be done had I brought it there to begin with), both rotors replaced (might as well at this point) and the now very necessary brake fluid swap.

Oh, for bonus points there's an outside chance the control module is fried due to my shenanigans too, not sure on that yet.

Hopefully I get her back tomorrow...

what flowers do you think I should get?

p.s. lest you think i could've used the traditional piston tools/c-clamp contraptions, the piston does not work with those. it doesn't even have the indents you'd find on an A4.

p.p.s. as it stands now, the very same PB system is in the Q7, Q5, D3 A8, the A5 and TT mk2 and possibly even the B8...we're slowly losing our ability to work on these cars mechanically :(

What a nightmare. I might just dish out the money for the rear brake change now after reading this. When technology goes wrong

probably wise since this will most likely only be done once for any C6' lifetime, judging by how many miles I got out of the stock brakes...

I just objected to spending the $ on top of the cost of the pads. had the car cooperated like it was supposed to, i would've saved $500.

Well at least you tried and gave us a good story!

wow, am I glad that I only got as far as pulling off the caliper, and seeing that the pads were still in great condition (with 65k miles) I said f'it, I'll do it another day!. Although I did buy new pads and rotors already....

So, it sounds like it was related to the retraction procedure with the vag-com? I couldn't get as far as you did retracting the parking brake in the first place, which was one of the reasons I decided not to go further.

When did you have to replace the fronts?

ouch -- although my brakes were replaced 10K ago... i was thinking of changing them out myself next time... hmmm maybe i'll think more about that one.

right, if the car won't retract the PB via vag-com, put everything back together and take it to the dealer...i did the fronts under warranty at just about 50k.

the irony is i thought the rears would be easier!

ouch -- although my brakes were replaced 10K ago... i was thinking of changing them out myself next time... hmmm maybe i'll think more about that one.

I honestly can't imagine the car ever needing rear brakes again, not before I trade it in anyway.

I think that I will let the dealer deal with my brakes, and probably everything else. I am all thumbs when it comes to technology.

great post of your experience. This would make me cautious to move too deep should I attempt to change ours. I am curious though if the motor is only a two wire motor or a stepper one. If it's a regular DC motor, I will try to reverse spin it assuming the VAG procedure is not straight forward.

Perhaps it would have spun but required some force? Our A6 came from Utah so not entirely a California no rust car like my 2 other Audis. Let's see if this one makes me swear a bit.

I think that I will let the dealer deal with my brakes, and probably everything else. I am all thumbs when it comes to technology.

The complication with the rear calipers + e-brake is probably why StopTech don't have replacements for the rear.

Thanks for sharing and sorry your "lesson" wasn't a good one. At least we can avoid your mistake.

great post of your experience. This would make me cautious to move too deep should I attempt to change ours. I am curious though if the motor is only a two wire motor or a stepper one. If it's a regular DC motor, I will try to reverse spin it assuming the VAG procedure is not straight forward.

Perhaps it would have spun but required some force? Our A6 came from Utah so not entirely a California no rust car like my 2 other Audis. Let's see if this one makes me swear a bit.

in theory it's supposed to retract the pressure nut inside the piston. i don't know if the brake fluid is supposed to evacuate or something in order for the piston to go back in, or some other behind the scenes process we mere mortals were deemed by audi to be too incompetent to comprehend.

either way, i'm really annoyed by it. not so much by my failure which might not have been preventable (yeah the counter-clockwise thing + tow were my fault), but by this restriction imposed upon us in the name of progress. yeah old e-brake systems are a pita with cables that go bad, etc...but at least they're well known/documented and easily remedied devils...

</rant>

and I was going to drive up to NH to have my brakes done;-)

sorry about all the xtra bucks they just got you for.

and I was going to drive up to NH to have my brakes done;-)

sorry about all the xtra bucks they just got you for.

haha, well if the vag-com procedure works, you're pretty safe to proceed....I just didn't trust the computer enough to back off.

To offset your loss, I'll get you a great deal on sunglasses. Hope that helps.

did you connect a battery charger to your car before running the basic settings?

http://wiki.ross-tech.com/index.php/Audi_A6_%284F%29_Parking_Brake#Caution.21

no, never did. it's not in the Bentley to do that either that I recall. in fact, the Bentley also tells you to run setting '10' before '7' to make sure you don't have any DTCs before proceeding, which the car passed with flying colors every time.

dealer says they were able to open the other piston fine with VAS, so maybe the charger is absolutely required. it could make sense since I suspect some kind of power issue, tho I never got a batt warning...

And here I just ordered the parts to do my '05. Guess I should have read this first. Oh well........

And here I just ordered the parts to do my '05. Guess I should have read this first. Oh well........

ha. try a battery charger, but if the computer shows an error, back away slowly...

That sounds like a plan.........."run Forrest, run".........

let me recite my tale of woe:


p.p.s. as it stands now, the very same PB system is in the Q7, Q5, D3 A8, the A5 and TT mk2 and possibly even the B8...we're slowly losing our ability to work on these cars mechanically :(

I agree with you 110%

I tried to fix issues on mine twice and still end up taking it to the dealer.