Bentley Allroad Brake Bleed Procedure? Seeing mixed threads

[jtozier]

Can someone post the proper brake bleeding procedure for a 2004 Audi Allroad 2.7t?

I am seeing a lot of mixed information. I am installing new brake lines, rotors, and pads. I have a motive pressure bleeder and 2 quarts of fluid.

One note, the fluid may have gotten below the reservoir tank as I was replacing one of the rear lines. I hurried and filled it and the new fluid turned a medium amber color as I could see it was able to mix with some old fluid. Hopefully it did not run dry, however I saw the rear hose stopped dripping fluid when this happened.

Now I have been seeing posts saying the pressure is anywhere from 8psi to 29psi. Plus the order is either front to back or back to front.

Any help would be appreciated. I have a vag-com cable showing up tomorrow so I could run the ABS pump if necessary. If you think I should when does that occur in the bleeding process?

Thanks

[4rings2turbos]

No problem if the reservoir went dry, you'll want to run the pump anyway to fully bleed. Start furthest from the reservoir to closest (RR, LR, RF, LF, ABS pump). Start with the pressure bleeder to get things close (8-12lbs is plenty) and then finish with two rounds of gravity bleeding. NOTHING gets a firm pedal like gravity bleeding.

Good luck!

[jtozier]

No problem if the reservoir went dry, you'll want to run the pump anyway to fully bleed. Start furthest from the reservoir to closest (RR, LR, RF, LF, ABS pump). Start with the pressure bleeder to get things close (8-12lbs is plenty) and then finish with two rounds of gravity bleeding. NOTHING gets a firm pedal like gravity bleeding.

Good luck!

Thanks! Now to turn ABS pump on I just need to have the key in the on position while using vag correct?

Also by gravity bleeding and during the pressure bleeding do I tap the peddle ever?

[Skianddestroy]

I just did this today on my '05 allroad. Bentley Manuel actually has the bleeding in reverse of normal.
" RF,LF,RR,LR."
I bled mine twice doing the traditional way first until I read the Bentley instructions. I'm pretty sure my reservoir got low when putting on the SS lines so I cycled the ABS pump several times with Vag-Com. Super easy, -abs module -basic settings -enter 002, then "do it". Be sure to have your LF bleed screw open so it can pump out the fluid. I did 20psi, I think the manual says 25psi or something.

[4rings2turbos]

Thanks! Now to turn ABS pump on I just need to have the key in the on position while using vag correct?

Also by gravity bleeding and during the pressure bleeding do I tap the peddle ever?

Yup, key on otherwise VCDS can't communicate with the controller. And you never need to touch the pedal thanks to the pressure bleeder :)

[glennda5id]

For vehicles with ESP, my instructions show 2 bar of pressure (29 psi) when bleeding the ABS pump using the following order.
LR
RF
RR
LF
Then leave LF bleeder open and bleed ABS hydraulic pump with vagcom.

[Jtozier9]

HAHA Here we go again! This is the info I saw in every other thread. Right there we have 3 different procedures.

I do have ESP. Isn't 29psi really high?

[glennda5id]

High compared to what? Braking systems can hit 1200 psi.

My source of data is alldatadiy.com which seems to source the data from ELSA.

There are different bleed orders if not pressure bleeding the system or if you don't have ESP. This may be the source of confusion with the bleed order. Alldata lists all three procedures and bleed orders depending on the factors I mentioned. When pressure bleeding though it clearly states 2 bar (~29psi) to bleed the hydraulic pump.

When I performed this work I bled at 29 psi. I also contacted Motive prior to doing this and they confirmed that there bleeder would not have issue at 29 psi.

[chris86vw]

I have a motive pressure bleeder

Then (mostly) ignore everything else. don't get a second person to pump the pedal, don't hook up vcds to activate the pump.

build your pressure with the motive, open valves, bleed brakes. You can gravity bleed a little at the end like 4 rings mentioned but I've never felt I had to do it on brakes, will do it on occasion, always do it on clutches though.

bled 100s of brakes, both at dealer and private shops or personally, never once used the abs procedure, it is not required. Heck call ross-tech they will likely tell you not to waste your time and they sell a lot of tools just to people who want to bleed brakes and do nothing else.

I do follow the order that 4rings mentioned though, it gets the bulk of the old fluid out faster so that if you happen to hit the pedal at all during the procedure there is less there to mix back in.

[glennda5id]

In order to bleed and refresh the fluid in the pump the system needs to be pressurized and the pump needs to be activated via vagcom. Not sure why you would skip that step unless you don't have vagcom.

[Jtozier9]

I had read some threads that reported people breaking seals at that pressure. So it made me feel like it was high. I agree that the ESP is probably why I had seen different write ups. In the end this just shows I need to get a Bentley asap.

It sounds like running the ABS pump is a simple final step.

[chris86vw]

In order to bleed and refresh the fluid in the pump the system needs to be pressurized and the pump needs to be activated via vagcom. Not sure why you would skip that step unless you don't have vagcom.

Day 1 working at a dealership new guy will ask where the 5234(or current version of bleeder) and whatever current version of the scan tool was at that time.

Day 1 shop foreman, master/ guild whatever person they ask will laugh at them and say waste of time..

Day 500 new guy will have never used the scan tool to bleed brakes and never had a problem

Not only do I have about 6 VCDS cables, I have had one since almost day 1 ross-tech existed and am currently chatting with their longest employee, and worked at VW/Audi dealers and several shops with factory scan tools. I have started to do the abs procedure maybe 1 or 2 times in the almost 20 years I've been repairing these cars on 100s of vehicles.


You can do it.. it is not in anyway required and the vast majority of cars never have it done with no problem.

so yeah I skip this and own many means to do it.

[4rings2turbos]

Some people, like myself are particular about changing as much old fluid to new fluid when they do a change, this will require the ABS pump. If you're not particular then feel free to skip it. Also, while the pressure at the lines may reach 1200psi the little plastic reservoir will not see high pressure.. no need to go higher than necessary.

[Skianddestroy]

I don't mean to hijack, but also don't want to start another similar thread.
I've bled my brakes and abs pump twice in reverse and normal order and still have a "soft" brake pedal. The pads I put on are ceramic, which I've never had. With the SS lines I just thought the pedal feel would be better. Maybe I need to bleed the system again...

[4xaudi]

Im going to jump in here also. Did a 17Z upgrade and B6S4 in the rear over the weekend. Have absolutely no pedal. Bled 3 time in both orders running a liter of fluid from each corner. Just cant get the pedal to firm back up. Used a Motive pressure bleeder at 25-30 psi. Also for some reason my Vag com wont recognize my abs module. Not a good weekend.

[4rings2turbos]

Both of you should try gravity bleeding.

[bpark1210]

When I switched in new rear rotors, pads, and SS lines I had a soft pedal as well. It took 5 total bleeds out the system to finally get a somewhat firm pedal back. I tried both the Bentley manual directions and the more traditional furthest to closest. To me it didn't make a difference until I fully bled through about 5 cycles. The good news is I was able to reuse the fluid after the first 2 flushes because all that was coming out after the first 2 flushes was clean brand new brake fluid. My VCDS couldn't get my ABS pump to run the bleed either.

[Jtozier9]

All went pretty well. Its a little soft but not too bad. I did two full bleeds and cycled the ABS pump twice. I may do two more in a week or so since I still have a quart of fluid in the pressure bleeder. I read that the fluid needs to be used within two weeks, is that true?

[G Men 08]

Good info in here. Thanks fellas.

[4rings2turbos]

I've never heard that the fluid needs to be used, that doesn't really make sense to me. It does make sense to bleed after a while but I recommend a gravity bleed. I gravity bleed when I do oil changes for the first few after I change lines or calipers. My pedal is ridiculously stiff.

[Jtozier9]

That's when you hang the drain bottle way up high with a long tube to the bleeder?

What's your procedure like and how long do you leave each nipple open for?

[4rings2turbos]

All you need is a little piece of clear hose to connect to the nipple then just open the bleeder and watch for bubbles coming out. Once the fluid runs clear with no air (a few seconds) then close the bleeder and move to the next caliper.

[Jtozier9]

How is that different than using the Genesis Cable Bleeder Bottle?

That's what I have and I am also adding pressure. Thanks for your help by the way.

[4rings2turbos]

It's not different going into a bottle, just saying that a small bit of hose is all that's needed for those that don't have a bottle.

And I'm not sure exactly why gravity bleeding is better at getting the last 10% of air out but it just is *shrug* could be something about the possibility of air being introduced by the pressure bleeder. As in it takes the vast majority of the air out but tiny micro bubbles get introduced?

[julex]

30psi can split old brake reservoir like it did on my car. 15psi should be still plenty... However there is nothing like alternative / old school pedal bleeding. Couple of notes on that. Get a length of tube that will reach from bleeder nipple to a jar, put some brake fluid into the jar so that the tube is submerged and go to tow with pedal bleeding. Open the bleeder and start pumping the brake pedal BUT ONLY 1/2 in, do not ever press it all the way in UNLESS you have a new master cylinder. If your master cylinder has some age to it, do not go more than 1/2 in as you're risking damaging piston seals on normally unused part of the bore.

When I bleed I used vacuum pump with reservoir instead of jar because the vacuum actually also retracts pistons in the calipers and helps to get rid of old fluid from there.

VAGCOM ESP pump bleeding (procedure is is not for ABS pump!!!) is a must if you got air in the system. This procedure only applies to interim audi models circa 1999-2000 with first version of ESP that has separate ESP pump installed undeneath the ABS unit. Air gets trapped in piping and the ESP pump itself and can cause issues. Newer models have better ability to get rid of air without any bleeding since the ABS pump is normally self-testing and circulating fluid around anyway so the air gets removed automatically in short order.

The fact is that after a good 2-3 rounds of complete bleeding of all corners you will still get a lot of bubbles out of system when doing the ESP pump bleeding via VAG-COM.

[Jtozier9]

I saw the ESP option in Vag-Com but you are saying it may not be applicable to a 2004 Allroad? I only ran the ABS pump.

[Audibot]

Pretty sure if you can't actuate the ABS pump, you need ~30 psi to open the valves and flow through. Also, tapping the calipers (especially after a 17Z/18Z upgrade) with a mallet while bleeding seems to help with getting the air out, in my experience. One additional thing to consider is, after all that bleeding and you can't get the pedal to be as firm as you'd like, is to adjust the rod that runs from the pedal to the brake booster so that you have less travel to engage it.

[julex]

I saw the ESP option in Vag-Com but you are saying it may not be applicable to a 2004 Allroad? I only ran the ABS pump.

I am fairly sure you don't have the ESP pump but it is easy to check. Look underneath ABS unit, if you have ESP pump then you'll black pump under ABS as well as couple of connectors and two extra hardlines coming into/out of it and then into ABS.

[chris86vw]

I read that the fluid needs to be used within two weeks, is that true?

Brake fluid is hydroscopic which means it absorbs water. Water is what lowers the boiling point of brake fluid and the main reason why you are supposed to flush it every 2 years or so.

An open container of brake fluid will start to absorb water as soon as it is opened. While I"ve heard 2 weeks or similarly close periods of time depending on the use of the car there is some give and take. If I bled mine on the first of the month and needed to do the GFs pos sentra at the end of the month I'd have no problem using it, the brakes never get near the point of boiling fluid. I certainly would not leave my pressure bleeder full and do my brakes again with it 6 months later.


A week later for a street car should be fine, doing some track days soon? maybe not.

[Jtozier9]

A week later for a street car should be fine, doing some track days soon? maybe not.

Haha no track days. Thanks everyone for the help. Solid thread.