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Discussion Starter · #1 · (Edited)
After I ran my MC dry (see earlier threads by me), I could never get my pedal hard again.

Guessing that it was possible that my MC was busted, I had it towed to a shop (a shop I hadn't used before; my previous mechanic is gone, his next-door neighboor, a specialty VW shop, is in the middle of a move.) Well, they announced that I had toasted my MC, they replaced it, and I could pick it up. Well, I went to pick it up, after hours on Monday, and the pedal was still mush. (Significant deflection w/o boost, easily floored w/ boost; the brakes sorta work, but not with a very confident pedal) I told them to try again. They called yesterday and said they took the MC out and put it back in again, and all was fixed.

I went back last night to pick it up... #*()&#(*T^E*(&%!!!*%(&%#&%!!!!!!!!! The pedal is STILL mushy! It's as mushy as when I decided to have a tow truck take it to the shop. Just puttering around the parking lot, and I have to press the brake halfway to stop the *bleep!*-ing car!

This morning I'm just going to have my wife drive me there and camp out in their waiting room until I'm satisfied (or I give up and call for a tow to the dealer), who will take who knows how long to get to it this time of year.

A few questions:
Assuming the shop has VCDS (if they don't, I'm calling for another tow... a shop can't advertise themselves as a VW/Audi specialist and NOT have VCDS (or a factory tool, I suppose)) what's the deal with bleeding the ABS module? Ross-tech has PULLED the instructions (http://www.ross-tech.com/vag-com/cars/absbleeding.html) from their site (as in, they are in archive.org, but that page is no longer there.) And for old instructions, some say to run ABS/Basic Settings/Group 002, others to run some "ABS Bleeding" button, yet others say to do ABS/Output tests. Which (if any) is correct?

The '04 Bentley (which is the one I have) unequivocally says that the brakes should be bled with a pressure bleeder, and that nothing special is necessary to bleed ABS.

I believe the shop when they say they've flushed the brakes (I'm assuming with a pressure bleeder), and that's AFTER I ran 2 quarts through myself (doing a manual bleed) after running it dry. If the Bentley is correct and fiddling with a scan tool isn't necessary, what could be the problem? It has all the symptoms of air in the brakes, but I'm getting tired of trying to get my pedal back.

I'm getting really sick of not having a car.
 

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As far as you not knowing or getting accurate info on how to bleed the ABS, I get the same thing also. There are many conflicting "instructions" out there.
I went through this on my '04 GLX 2 years ago. I have read and heard that my car requires the ABS activation to bleed the brakes properly, but then I read the Bentley, it doesn't say squat about that, other than what you stated, which is, use a pressure bleeder.
I ended up just manually bleeding the brakes with the help of my wonderful wife. It seemed to take forever to get a hard pedal.
But I will say this, to this day the brakes on my '04 aren't as good as the brakes on my '98 GLS. My '98 has a much more responsive firmer feel than the '04.
I'm still suspect that their is a tiny air bubble somewhere in my brake system.
I know this post doesn't help you, but be assured you are not alone.
 

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I know that when I bleed brakes on a VAG car, I use a motive power bleeder and do all the corners 5 times minimum. anything less than that, and it seems like the brakes are always spongy. on my 99 Passat and 05 B6 A4 (1.8t), that's what it took; I'm guessing they stopped bleeding when they stopped seeing bubbles, instead of going whole hog and doing each corner 5 times. there's a bubble in there.
 

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I'll just add not to go crazy with the pressure when using the Motive pressure bleeder -- I have heard that you might crack the reservoir.
 

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I know that when I bleed brakes on a VAG car, I use a motive power bleeder and do all the corners 5 times minimum. anything less than that, and it seems like the brakes are always spongy.
I've never gone around the car more than once to fully change the fluid, and have always had excellent brakes. But then again, I've also never let the MC run out of brake fluid when doing it. One thing I have done though, when having the calipers unbolted for whatever reason, is to tilt them by hand so the bleeder is straight up, and purge some fluid out that way. Otherwise, is seems pretty likely that at least some air will be trapped in a/the caliper(s).
 

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The car is designed so that with the car sitting level, the bleeder is connected to the top of the cylinder and all air can be bled out.
With the bleeder pointing straight up, if there is air in the cylinder some would likely be trapped in the back of the cylinder.

Bleeding at each wheel should be done quickly, without pauses so that the flow is faster than the tendency for the bubbles to move back up the pipe.
 

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I'll just add not to go crazy with the pressure when using the Motive pressure bleeder -- I have heard that you might crack the reservoir.
I use 15 psi max on the motive. while Tomvw says to do it quickly, I've always noticed that there's always tiny bubbles that seem to coalesce over time, no matter how clean the flow may be after the first couple of times - hence my comment about 5 cycles or so.
 

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I use a check-valve in series with clear silicone hose, which eliminates the whole two person 'open bleeder-push brake-close bleeder-let up pedal' routine. I also prefer to start by removing the screen basket, then drawing out the old fluid in the reservoir. Wipe the insides of the reservoir, then fill with fresh brake fluid. Now just open each bleeder in the usual order, pumping the brake pedal until only new fluid is discharged.
 

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I've never had a problem with using my Motive Bleeder on any of my cars, the Passat has been using this tool for the last 2 BF flushes.

@ ylwagon, how do you remove that screen basket? I drain the resevoir by removing the slotted yellow cap off to the left side of the res, and then place clear tubing on the tap and then apply suction. Ask me how awful DOT 4 tastes! it lingers on your tongue for only about 24 hours :puke:
 

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That basket can be difficult the take out, especially the first time, being that it latches into the reservoir. I had to just carefully pry around the rim until it released. I'll admit that this is pretty unnecessary; it's just to see into the reservoir better afterwards.
 
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