Brakes don't work until pedal is almost to the floor (After brake job)

[Spike00513]

Hi everybody, any help/input on the issue would be greatly appreciated

The car is tiptronic

Here's what happened. I changed pads and rotors on all for corners and upgraded to SS brake lines.
In order to push the rear caliper pistons in when replacing the pads, I used the specific brake tool required to turn the pistons while pushing them

I gravity bled the brakes from nearest to farthest using Pentosin DOT4 brake fluid. One mistake I may have made is that I didn't siphon out the fluid from the resesrvoir via the lower left flat-head screwdriver opened cap:



Instead, I used a syringe to pull out fluid from where the large screw-on cap goes. I siphoned out brake fluid until empty, then it would slowly fill, then siphon out again. I did this at least 10 times and got what looks like 2 or 3 times the volume of the reservoir out. Then I filled with fresh fluid, bled, used a liter of new fluid, and eventually, no bubbles were coming out. I also tapped on the lines near the calipers to free up any air bubbles clinging to the walls. I gravity bled the system, which took a while, but I made sure to keep the reservoir topped off

When everything was done, I lightly pumped the brake pedal a few times with the car off. No pressure build-up, nothing.

I turned the key to the on position but didn't turn the engine on. I lightly pumped the pedal and pressure built up - it got really stiff

I turned the car on(engine on) and the brake pedal goes almost to the floor before working. I applied the brakes and checked for leaks. I looked at the brake line fittings and on the floor/wheels for dripping brake fluid - nothing

I bedded the pads in, and still, the pedal has an abnormally high travel distance. Once I get to that engagement point, the car stops. There's no lack in braking power

I'm thinking that because I siphoned more fluid out of the reservoir than it can hold, it must have vacuumed the air introduced by replacing the brake lines into the system and into the ABS pump?

Any ideas on what I did wrong? How to fix it?

Thanks in advance

[sa_seahawker]

If it's a manual, you have to bleed the clutch, too.

[Spike00513]

I apologize, it's tiptronic. Updated.

[old guy]

Simply put, you still have air in the brake hydraulics. did you use a power bleeder or did you use the pump/hold/bleed/release method?

[b6_quattro]

I always bleed brakes starting farthest from the master cylinder and work my way closer. just keep bleeding them...

[Spike00513]

I gravity bled. Starting at the drivers side front, I put clear tubing over the nipple and led it into a catch bottle. I cracked the nipple and fluid slowly came out and it took about an hour to do the whole thing. I didn't touch the pedal. I kept topping off the reservoir so it wouldn't run dry during the gravity bleed.

I did this before two years ago but the difference is this time, I replaced the brake lines (which I didn't do during my gravity bleed two years ago)

[evo_ski]

Instead, I used a syringe to pull out fluid from where the large screw-on cap goes. I siphoned out brake fluid until empty, then it would slowly fill, then siphon out again. I did this at least 10 times and got what looks like 2 or 3 times the volume of the reservoir out.

Sounds like you introduced a ton of air into the system including into the abs module which is pretty difficult to bleed (or so I hear). You never want to let the fluid in the reservoir go empty, which it sounds like happened multiple times when you siphoned the fluid out. In short, I am not certain gravity bleeding will work for you to get it out now. You will likely need to use a pressure bleeder, or the old 2 man pump the brake pedal maneuver.

[Spike00513]

Does anybody know if it's possible to cycle the ABS pump by braking? I read on another Audi forum that it's possible to activate it that way - I'd ask the person who posted that more but their profile isn't active. In order to avoid a 2nd person I could just stick a piece of wood between the pedal and seat to pressurize right?

[evo_ski]

You have to have the person hit the pedal and then you close the bleeder before the pressure goes away. Unfortunately it isn't really possible without a second person. I believe the only way to cycle the abs pump other than by driving it and stomping on it to activate it is to cycle it with the vagcom software.

[jjvwg]

If you don't have vag-com you can just get the ABS to activate to get the air bubbles out of ABS module. All the vag-com activation is doing is activating it the same as if you were drivin minus the driving part. I would do a two man bleed operation if you can't get your hands on a power bleeder in a timely manner and then go out and drive. If the brakes won decent, put two wheels off into the dirt on the side of the road and hit the brakes to activate the ABS. Do the a few times to clear the air bubbles! This should get you all fixed up

[Seerlah]

Bentley tells you bleeding procedure (caliper sequence). I think the B5 (what I have) differs from the B6, so my procedure won't help. But mine was right rear, left rear, right front, left front. I had air in mine when I finished, and simply just bled till they were right. The rears need more bleeding than you may think. I gave up on the bubbles (was clear to me), and just stopped after a certain time (power bleeder). Worked fine after that.

[ADCS]

Power bleeder - Closest to further - FL, FR, RL, RR
Manual method - Farthest to closest - RR, RL, FL, FR
I doesn't really matter, just be consistent.

When I did my calipers/lines I bled the brakes 5-6 times doing the two person manual method with minimal success. At that point my wife got annoyed mashing the pedal so I picked up a power bleeder and did the bleed sequence 2 additional times and now all is well. I also did some driving to activate the ABS module after the manual bleeding and before the power bleeding.

If you do the manual method, put a block of wood under the brake pedal so that the pedal does not go all the way to the floor.

[Spike00513]

Also, if I pump the pedal a few times prior to braking, all is well. Without the pumping, it goes easily to the floor

[old guy]

My advice is to get a power bleeder and bleed the brakes again. I have used a power bleeder for many years and never had an issue with a soft pedal. Otherwise you risk introducing air into the system and it can be a real bitch to get it back out.

[wolfdog]

Power bleeder FTW. Worth the $40 or $50 I spent. Tried to build one myself using a bug sprayer and other stuff. Waste of money. Motive works well, saves time and makes it a 1-man operation. Where are you? Post in a regional forum and maybe someone can visit with one.

[Spike00513]

Where are you?

San Diego

[Spike00513]

My advice is to get a power bleeder and bleed the brakes again. I have used a power bleeder for many years and never had an issue with a soft pedal. Otherwise you risk introducing air into the system and it can be a real bitch to get it back out.

Before I order the motive power bleeder, do you think that the brake master cylinder could have problems? I drove it around today and tried to activate ABS by braking really hard (have done this before). This time, it didn't work. The pedal shuddered but the light on the dash didn't flash. I'll try in a few days when it rains.

When I first bled the system, after about .75 liters of new fluid, there were no more air bubbles coming out. I bled a little again today, and air came out from the rears. I did the 2-man brake bleed. I didn't push the pedal all the way down, but if I went too far it got to a certain point where the master cylinder would start screaming if I'd keep pressing. I'm thinking maybe the master cylinder is bad?

[diagnosticator]

Also, if I pump the pedal a few times prior to braking, all is well. Without the pumping, it goes easily to the floor

What you described above, is typical when there is air in the brake hydraulics.

[rollerton]

I don't know what it is specifically about some Bosch / Audi ABS systems, but you will get old and die before you get a firm pedal by manually/ gravity bleeding them. Power Bleeder usually does it. Usually.
And even then it can take a little repetition...

[seanf86]

I got a rock hard pedal on mine doing the pump and hold, get someone to pump and hold and crack the lines loose going into and leaving the abs module then bleed the whole system again, mine was slightly longer travel then before, after some stop and go driving the few remaining bubbles worked there way out in a week and the pedal was right where it was before.

[OMG_SHARK]

San Diego

If you need a second person on the pedal while you bleed it PM me. I can swing by your place and help you this afternoon if you want.

[sa_seahawker]

If you need a second person on the pedal while you bleed it PM me. I can swing by your place and help you this afternoon if you want.

The two man manual pedal bleed is generally regarded as a bad idea with these cars. If you force the pedal to the floor, you may run the risk of damaging the MC seals. While I'm sure you may be able to get away with it, the risk of damaging the MC when you could've dropped the $40 for a pressure bleed kit was too high for me. Also, vacuum bleed kits are garbage. Ask me how I know.

[ADCS]

BTW, what pads did you use? And did you bed them?
Even after getting all the air out of my lines the pedal felt like mush for the first 100kms after bedding them. That is typical for the pads I chose but now the pedal is very firm.

[Spike00513]

BTW, what pads did you use? And did you bed them?
Even after getting all the air out of my lines the pedal felt like mush for the first 100kms after bedding them. That is typical for the pads I chose but now the pedal is very firm.

Pagid 4B0-698-151-AF-M73. Yes I bedded them. My plan for this week when I get VCDS:

(Bleed sequence = FL,FR,RL,RR)

1. Check brake lines for proper operation by pumping brake pedal 10-15 times then cracking corresponding bleeder valve and checking for fluid gushing
2. Center the rotors by securing them to the hub with axle nuts in between rotor mounting surface and lug bolts
3. Bleed ABS via VCDS/Vag-Com
4. Place piece of wood or something between seat and pedal for constant pressure while making sure to keep the pedal within normal travel distance
5. Pressure bleed entire system? How does this work? I built my own pressure bleeder from a garden sprayer. With my finger over the outlet port, I can get it to hold 30PSI. Provided that I can get it onto the reservoir without leaks, I have to keep the pressure bleeder full of brake fluid? It came with a straw that connects to the outlet and goes to the bottom of the bleeder (similar to drinking through a straw from the bottom of a glass.) When the system is pressurized and I crack a bleeder valve, the fluid escaping will create a vacuum and suck the new fluid from the power bleeder in?)
6. Bleed master cylinder if possible
7. Make sure fluid is below MAX line in reservoir to allow for expansion when brakes are retracted
8. Bleed master cylinder if possible
9. Check brake pedal quality after 100 miles and maybe a few ABS activations in the wet

Total of 2 liters fluid required?

Please correct me if I'm wrong, I'm trying to determine what's best to use and in what order rather than throwing everything I've got at it (Pressure bleeder, CVS pharmacy syringe adapted to fit onto the bleed screws, manual brake pedal bleed, etc.)

I've bled a sportbike before (no ABS, ESP, or anything like that) and I did a well-known bike trick where you use zipties to keep pressure on the brake lever overnight. The next day, the brakes were rock-hard. Squeezing with medium pressure from one finger could send you flying over the handlebars. Has anyone done this?

[SlickFix]

I built my own pressure bleeder from a garden sprayer. With my finger over the outlet port, I can get it to hold 30PSI. Provided that I can get it onto the reservoir without leaks, I have to keep the pressure bleeder full of brake fluid?

How do you plan on getting the fluid into the reservoir and still maintain 15 PSI(30 PSI is too high, btw) without a cap that's custom made for our reservoirs? You seem to be avoiding purchasing a good power bleeder for some reason. If you don't have the funds, perhaps there's another AZ member close by that has one you may borrow?

2 liters of fluid should be enough, but it depends on how much air you have in the system.

[DiertyEuroSpec]

I can sell you my used motive power bleeder with associated hardware for like $30 bucks if you really don't want to pay full retail

[Spike00513]

I can sell you my used motive power bleeder with associated hardware for like $30 bucks if you really don't want to pay full retail

Thank you for the offer, I'd take it if I hadn't just built my own. I saw the retail price and shipping and decided to build one from an identical garden sprayer for 20$. It takes some tape and teflon around the reservoir threads to keep from leaking but it works

[Spike00513]

How do you plan on getting the fluid into the reservoir and still maintain 15 PSI(30 PSI is too high, btw) without a cap that's custom made for our reservoirs? You seem to be avoiding purchasing a good power bleeder for some reason. If you don't have the funds, perhaps there's another AZ member close by that has one you may borrow?

2 liters of fluid should be enough, but it depends on how much air you have in the system.

I picked up a B6 reservoir cap from a junkyard and it works. I should be doing the procedure sometime this week.

[Charles.waite]

Pagid 4B0-698-151-AF-M73. Yes I bedded them. My plan for this week when I get VCDS:

(Bleed sequence = FL,FR,RL,RR)

1. Check brake lines for proper operation by pumping brake pedal 10-15 times then cracking corresponding bleeder valve and checking for fluid gushing
2. Center the rotors by securing them to the hub with axle nuts in between rotor mounting surface and lug bolts
3. Bleed ABS via VCDS/Vag-Com
4. Place piece of wood or something between seat and pedal for constant pressure while making sure to keep the pedal within normal travel distance
5. Pressure bleed entire system? How does this work? I built my own pressure bleeder from a garden sprayer. With my finger over the outlet port, I can get it to hold 30PSI. Provided that I can get it onto the reservoir without leaks, I have to keep the pressure bleeder full of brake fluid? It came with a straw that connects to the outlet and goes to the bottom of the bleeder (similar to drinking through a straw from the bottom of a glass.) When the system is pressurized and I crack a bleeder valve, the fluid escaping will create a vacuum and suck the new fluid from the power bleeder in?)
6. Bleed master cylinder if possible
7. Make sure fluid is below MAX line in reservoir to allow for expansion when brakes are retracted
8. Bleed master cylinder if possible
9. Check brake pedal quality after 100 miles and maybe a few ABS activations in the wet

Total of 2 liters fluid required?

Please correct me if I'm wrong, I'm trying to determine what's best to use and in what order rather than throwing everything I've got at it (Pressure bleeder, CVS pharmacy syringe adapted to fit onto the bleed screws, manual brake pedal bleed, etc.)

I've bled a sportbike before (no ABS, ESP, or anything like that) and I did a well-known bike trick where you use zipties to keep pressure on the brake lever overnight. The next day, the brakes were rock-hard. Squeezing with medium pressure from one finger could send you flying over the handlebars. Has anyone done this?

None of those steps make sense if you have a power bleeder.

the steps with a power bleeder:
1) activate ABS system with VCDS
2) fill power bleeder
3) attach power bleeder
4) pressurize power bleeder to 15psi
5) corner by corner, bleed calipers using a drain hose that attaches firmly to the bleeder nipple (so no air is introduced by a loose hose) and you can verify the bubbles are gone with a flashlight shining through the clear hose
6) ???
7) profit


Its really that simple. I don't know what your steps above are trying to achieve. I would get 2L of brake fluid and push most if not all through the system. Bleeding the clutch isn't necessary unless you suspect air in the clutch system.

and DO NOT touch the brake pedal while bleeding with the power bleeder. You could damage something. Also make sure your car is on relatively level ground. That helps get the system bled properly.

[Spike00513]

I got a rock hard pedal on mine doing the pump and hold, get someone to pump and hold and crack the lines loose going into and leaving the abs module then bleed the whole system again, mine was slightly longer travel then before, after some stop and go driving the few remaining bubbles worked there way out in a week and the pedal was right where it was before.

Where did you bleed from? I know I have air in the master cylinder and ABS.




I'm having trouble rotating the picture. In this case, let the right side = top when facing the car from in front. Lines 5 and 6 on the ABS come from the MC. I'm assuming the rest are outlets to the brakes. If you cracked all 6 this means you sort of "bench bleed" the MC, and manually bleed the ABS? The valves in the ABS don't operate without cyling it with VCDS or hard braking activation, so I'm assuming that you can't get all of the air out with the manual method

[Spike00513]

Ok, so some people say I should do 2 bar. Some say 10 psi. Some say 15 psi. Which is better and why?

Here's what I found in the manual:

Brake Bleeding: Service and Repair
Bleeding, Vehicles With Electronic Stabilization Program (ESP)

Bleeding sequence for vehicles with Electronic Stabilization Program (ESP)

Unlike ESP 5.3, ESP 5.7 does not incorporate hydraulic pump -V156-. Therefore it is not necessary to bleed the system with the diagnostic tester.

Important:
A pressure of at least 2 bar is required for bleeding the ESP hydraulic unit. Therefore always check the pressure setting on the bleeding device.

Only use the brake pedal depressor when installing brake system components, and bleed the system afterward.

The brake pedal depressor is referring to V.A.G. 1869/2, which the manual instructions tell you to use when removing brake hoses or calipers to "depressurize the system", and to remove it after the calipers or hoses are reinstalled.

[Charles.waite]

Don't disconnect any of those lines. You'll just introduce more air into the system that way.

Seriously, you're over thinking this. Just activate the ABS through Vagcom and bleed the brakes using a power bleeder. You might go through a decent amount of fluid, but thats the best way to do it...

[SlickFix]

Don't disconnect any of those lines. You'll just introduce more air into the system that way.

Seriously, you're over thinking this. Just activate the ABS through Vagcom and bleed the brakes using a power bleeder. You might go through a decent amount of fluid, but thats the best way to do it...

+1.

Charles is right. You are way over-thinking this process. VCDS will activate the ABS for you, then it's just a simple process to bleed the brakes.

[Spike00513]

Update:

I used VCDS to engage the ABS brakes output test and did it about 5 times and made sure to bleed the brakes after each time. I got a lot of air out and after the ABS output tests, I pressure bled the system at 20 PSI in the order of closest to farthest from the MC. I used 2L brake fluid in total.

I took the car out for a drive and the brakes were the same. They didn't work until the pedal was almost to the floor. I read in the manual that after brake work it's necessary to do 1 ABS stop (by brake work I mean anything that gets air into the system)

After a bit of driving to warm the car and brakes up, I did 2 ABS stops and after that the pedal started to get better. The softness/sponginess is 75% gone and I'm hoping that after a few hundred miles and maybe some more ABS stops, I can bleed a little more and will have a perfect pedal. I'll keep an eye on the brake fluid level.

I rebuilt the rear calipers (torn dust boots at 90k) and put anti-sieze on the brake pad ears and anti-squeal on the back of the pads, so far no squealing and it seems like I'm getting normal MPG again

[diagnosticator]

I have never needed to activate the ABS on the B6, for the following reason as posted already:"Unlike ESP 5.3, ESP 5.7 does not incorporate hydraulic pump -V156-. Therefore it is not necessary to bleed the system with the diagnostic tester."

[Spike00513]

I have never needed to activate the ABS on the B6, for the following reason as posted already:"Unlike ESP 5.3, ESP 5.7 does not incorporate hydraulic pump -V156-. Therefore it is not necessary to bleed the system with the diagnostic tester."

The manual also mentions that to manually bleed the ABS without VCDS, 35psi is required. With 30psi applied to my brake fluid reservoir with a pressure bleeder, it starts to swell and looks like it will explode

[diagnosticator]

The manual also mentions that to manually bleed the ABS without VCDS, 35psi is required. With 30psi applied to my brake fluid reservoir with a pressure bleeder, it starts to swell and looks like it will explode

Yeah, that would be alarming alright. I use less pressure, 20 to 25 psig, and that has always been sufficient pressure to get the air out of the ABS valve block. When the system is pressurized, the air bubbles trapped in the hydraulics, get compressed to a lot smaller size compared to the unpressurized condition where the air bubbles in the system are a lot larger, and can block effective bleeding of air from the system. The Bosch ESP 5.7 is functionally different compared to the ESP 5.3. Consequently, pressure bleeding alone is effective since the there is no charge pump. Therefore, activating the ABS does not perform the bleeding assist that activation does for the ESP 5.3.