Brake Bleeding Problem
 

Hi,

I am really hoping someone can chime in with helpful information as I am about to go crazy out in my garage...

Over the weekend I replaced the pads on my X5 (2005 4.4). After that, all was going well, but I also wanted to change the fluid, so I opened the pass rear bleeder to drain while I was doing other projects. Well, of course I FORGOT and left it open allowing the reservoir to empty.

OK...so I figured I was in for a hassle now in terms of bleeding but I had no idea the frustration I had just unleashed upon myself. I have now been at this for hours trying to get brakes again.

Starting at the passenger's rear, I have worked my way around in sequence (pass rear, driver rear, pass front, driver front) a total of three times now.

As a first step, I opened the pass rear bleeder and let it drain forever, then followed with the others as listed. After all of this, I have nearly no pedal at all. At times I will get a mushy pedal, but after starting the car it will go to nearly nothing.

Aha! I thought...I must have air trapped in the ABS unit, I will cycle the unit using DIS and opening the bleeders! ...and still nothing.

I really don't know what could be going on at this point, I have run an entire 12 oz bottle of fluid through this blasted thing, and there has been no signs of air at the bleeders and no improvement in the pedal.

As it sits now, the thing is undrivable; it barely has enough braking force to keep itself from rolling away at idle!

FWIW I have done this job (and line replacement, master cylinders, etc, etc) I don't know how many times in the past (other vehicles) and I have never had an issue like this! Anyone have any further suggestions as to what could be going on? It is driving me nuts here - thanks!

ABS pump is probably empty also. You are not going to bleed the system unless you have the correct software and knowledge on how to bleed the ABS pump.

Good Luck.

I tried to do that, but I don't have a pressure bleeder - maybe that is the problem. Using DIS and just opening the bleeders and relying on gravity may not cut it...? I wasn't really clear on whether it was required or not. The instructions refer to using a pressure bleeder to flush the fluid; but once that is done I wasn't sure. Could be for the sake of time, could be it is necessary I suppose.

Actually I see many tales of woe here on the forums, and I find myself a bit irrationally hostile that something every toothless hillbilly has done since the dawn of the auto has turned into a fiasco that many professionals cannot sort out properly (including some BMW technicians it would seem.)

I am going to try the two man 'pump & hold' method again, but this time with the engine running, and I am going to try and find a pressure bleeder. Not overly optimistic on finding that last one locally, but you never know...most seem to operate on vacuum at the bleeder rather than pressure at the reservoir; and I am not sure it is quite as good. Or, if I can find a spare reservoir cap, that would be great too. Now, if only I didn't have to work tomorrow I might be able to get this sorted out! :)

You are joking right? You are relying on gravity to pull the fluid through the system?

Sounds like it is going to be a hassle to fix.

You can't use gravity. You may have been able to do it with two people, but that wouldn't necessarily have flushed what was in the ABS controller. Once you got air in the ABS controller you were hooped.

Not a toothless hillbilly here, but I have worked on vehicles since the mid seventies, and have done brake jobs on vehicles from the twenties (a truck with mechanical linkages to the rear drum brakes) to current models. But I don't flush the fluid in my own BMW brakes. I don't need the hassle, and the dealer has trained personnel and the appropriate tooling to do it quickly and easily.

Try this poor mans version of reverse flush:

Fill a jar with new brake fluid.
Attach hose (shorter the better) from bleeder and submerge in the jar.
Remove cap from brake reservoir.
Pump pedal to force fluid out into the jar - and then suck fresh fluid in on the release.
Keep eye on reservoir level and repeat until no more bubbles appear.
Repeat each corner.
Then follow up with traditional pump/crack/bleed for any remaining trapped air bubbles.
GL!!!

If no work then tow to dealer.

I have chased crap brakes on my E36 for years and have tried everything to get air out of the system. You may have to bench bleed the master if it was run dry. The BMW procedure as per DIS is to pressure bleed the system, disconnect the pressure, run the bleed routine while pumping the pedal for each corner. Pressure bleed again, then no pressure bleeding once again. If you have the software it should walk you through it. I think this works to get small bubbles out. To try and evacuate an entire system or length of air, you may have your work cut out for you.

When I bleed (the track car), I switch fluid fluid colours so I can see it come out. If you are certain the fluid is flushed, then the air is in the master, ABS unit or the pump circuit. You may find that cracking the fittings at various points throughout will help bleed the air out in those sections. Always keep the pressure bleeder on and full when your doing this to avoid making it worse.

I haven't got into these brakes yet, so my experiences are only from years of messing with my E36 brakes, so take it with a grain of salt.

I'm not sure what others have suggested yet but basically sounds like you have air in the lines and the best way to fix it is with two people.

You need to do this with the car "off" and the abs disconnected by removing the abs relay and fuse.
Have your friend, girlfriend, wife, kidnapped neighbor whatever apply the brake inside while one caliber at a time open the bleeder to allow the air out until you have a clear stream of fluid bleeding out. (you'll now because you'll hear air and start to see foamy fluid then clear fluid)

Air is compressible this is the problem, brake fluid is not although it does start to boil at certain points sometimes moisture can get in the lines too which is why it's very important to bleed off air which has moisture in it.

The Bentley repair manual says that air can get trapped in the system (I think to the ABS module). Apparently, BMW's bleeder tool vibrates the system to loosen up this air, allowing it to escape. With out the vibration, the air won't move. So if any air gets into the system, the repair manual recommends you have BMW bleed the system. If no air gets in the system, you should be ok.

Since air has entered your system, I would say that you should just take it to a BMW shop, presuming you can get it there. If it's undriveable, maybe you can get them to come to you? Otherwise, towing is probably your only option.

I had this previously.

This is from my build thread on Xdrivers:

Unfortunately after quite some time of trying to bleed the brakes we had to give up as there was air trapped in the system which needed the pressure system and diagnostics laptop to be able to open the valves (unsure which but basically closes off the rear bias so you can not bleed them/use them. Fronts can still be bled as per normal). So in came our very own Jason from BWChiptune to sort it:

http://i2.photobucket.com/albums/y15.../BBKBleed1.jpg

http://i2.photobucket.com/albums/y15.../BBKBleed2.jpg

http://i2.photobucket.com/albums/y15.../BBKBleed3.jpg

http://i2.photobucket.com/albums/y15.../BBKBleed4.jpg

http://i2.photobucket.com/albums/y15.../BBKBleed5.jpg

Thanks RajB - I actually stumbled across this information in your original thread and it was helpful. I had another go at it last night (day 3) but this time with pressurizing the reservoir - that seems to be key.

After doing so a lot of air came out of the system, particularly at the pass/rear bleeder. It is better now; which is to say I have resistance/fairly firm pedal with the key off; but with the engine running it is still going pretty much to to floor. So while terrible, it is an improvement over day 2.

I am going to repeat the process again this evening hopefully, and maybe it will improve again after making another. It is interesting that I don't think I have seen any air from the fronts, it does seem as though it is the rears that are the issue.

What is the device on the floor? Seems awful robust for a mere catch can...?

---

Aha, got it:

http://www.liquid-levers.com/shop/pr...79ee83f1f1f157

___

Thanks!

Oh yes, also - Do you remember why it states "A second person is necessary for this procedure?"

I am not sure what their role is. If the reservoir is pressurized, and the bleeder is opened, and the bleeding cycle started with the computer; it seems like a one man job?

Here's what my Bentley manual has to say about brake bleeding. Seems as if your "helper" is required for some brake pedal duties.

I am researching this subject as well. I know mine hasn't been changed in the 3 years I've owned my X. Who knows when and if it was done before.


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On this topic. I guess a vacuum type bleeder is not the way to go? They want pressure. I wonder if it makes a big difference? Reason being - I
picked-up a vacuum-bleeder from harborfreight the other day...


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I recommend using a pressure pump, Il maybe add a brake bleeding/fluid replacement to my list of DIYs for those who want to do it but dont have the specialty tools.

Glad the info is helpful.

Yes it is a pressure system Jason is using and if using this sort of system then it is a one man job.

The reason, the fronts are fine is that the valves close to the rear when the fluid has drained out of the system so allowing the fronts to remain intact. Jason said you have to use the software (autologic etc) to open the valves back up to allow the fluid to fully pass through and allow the proper bleed of the system and fill the pipes back up and remove the air.

Just using the pressure system on it's own will not allow the system to still be bled.

We were at it for a couple of hours with loads of air coming out but still never got anywhere until Jason hooked up the Autologic to cycle the valves open.

Garrett.fell; thanks for that information also. Right off the "holding the pedal to the floor" seems to answer my question and provide another step to try as I have not been doing that.

I have been allowing the pedal to return to its upright position, so it seems this is not the correct procedure.

Hold on. Watch this. Do not hold brake pedal to floor.

3min mark, explains why.

https://www.youtube.com/watch?v=04DZuyzAQDQ

I missed my next update, so I'll give a combined Day 4/5 :)

Day 4 I was able to properly pressurize the reservoir. I performed a full bleed, at each point I pressurized the reservoir, opened the bleeder. Allows the attached hose to fully fill, submerged in a container of brake fluid. Pumped the brakes 5 times. Ran the DIS bleed procedure. Pumped the brake 5 times. Started the engine, pumped the brake 5 times. Ran the DIS bleed procedure. Closed the bleeder. Sounds ridiculous; but I got a TON of air out of the system, mainly at the passenger rear.

So, after this raindance, I had a fairly firm pedal with the engine off, but it was still soft with the engine running.

The next day after work, I basically repeated the exact same process. Afterwards, I had a pedal that was rock solid with engine off, and usable with the engine running. I still didn't think it was quite as good as before, but at least I could drive it and bed the pads in.

Today I drove it to work, and they feel great. Not sure why it is any different than last night, maybe the fluid was a bit aerated; but they are fantastic now.

I sometimes like to check it after driving a few days to ensure no additional air worked its way back out of the system, so I'll probably do that this time too - but for the time being I am just happy to lay it to rest - What a fiasco!

You can be darned sure I'll watch fluid levels like a hawk the next service; that is for sure!

But yeah, pressure bleeding running the "Bleed Procedure" routine were key. It was difficult enough and took enough time even with them, I don't think it ever would have been possible without them. I suppose this is pretty typical of any modern AWD vehicle, but it was a frustrating bit O' learning for sure. Thanks again to everyone who helped!

I missed my next update, so I'll give a combined Day 4/5 :)

Day 4 I was able to properly pressurize the reservoir. I performed a full bleed, at each point I pressurized the reservoir, opened the bleeder. Allowed the attached hose to fully fill, submerged in a container of brake fluid. Pumped the brakes 5 times. Ran the DIS bleed procedure. Pumped the brake 5 times. Started the engine, pumped the brake 5 times. Ran the DIS bleed procedure. Closed the bleeder. Sounds ridiculous; but I got a TON of air out of the system, mainly at the passenger rear.

So, after this raindance, I had a fairly firm pedal with the engine off, but it was still soft with the engine running.

The next day after work, I basically repeated the exact same process. Afterwards, I had a pedal that was rock solid with engine off, and usable with the engine running. I still didn't think it was quite as good as before, but at least I could drive it and bed the pads in.

Today I drove it to work, and they feel great. Not sure why it is any different than last night, maybe the fluid was a bit aerated; but they are fantastic now.

I sometimes like to check it after driving a few days to ensure no additional air worked its way back out of the system, so I'll probably do that this time too - but for the time being I am just happy to lay it to rest - What a fiasco!

You can be darned sure I'll watch fluid levels like a hawk the next service; that is for sure!

But yeah, pressure bleeding running the "Bleed Procedure" routine were key. It was difficult enough and took enough time even with them, I don't think it ever would have been possible without them. I suppose this is pretty typical of any modern AWD vehicle, but it was a frustrating bit O' learning for sure. Thanks again to everyone who helped!

What kind of setup did you use
to pressurize the reservoir?


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any modern ABS vehicle, AWD doesn't impact it.

Glad you got it sorted.

Nice, crazy for sure, but something we expect these days with modern cars and DIY.

Garrett, if I had it to do over again, I would have bought one of the pressure bleeding systems. But I actually modified a cap from another BMW (2002 M Coupe) and threaded a NPT fitting into it. I set the compressor regulator just under 30 PSI and attached it. It worked, but I had to move fast to keep it from depleting the reservoir again.

http://www.thelawrencebarn.com/josh/reservoir.JPGhttp://www.thelawrencebarn.com/josh/reservoir2.JPG

Cool. I was thinking of making something similar. You're suggesting it really pushes the fluid out quickly? Maybe when I make mine I'll put something in-line to cut the air-volume down a bunch (like a little block in the middle with a little hole drilled in it. Much like a cylinder leak-down testing tool).


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Ughh... and I was thinking that flushing my brakes myself would be a safe DIY for someone like me. Now I am not so sure.

It really SHOULD be easy - just don't be stupid like me and let it go empty!

The whole brake job & bleeding was a cakewalk and over quickly. It was the aftermath of my carelessness that caused all the headaches. Honestly, even just gravity bleeding would have worked; it is just that it takes SO LONG that it is easy to get distracted/forget to check up on it.

Power flushing is super-fast, the fluid flows from the bleeder in a stream. Using this rigged setup the entire reservoir would have been depleted in just a couple minutes if not watched carefully. If you do it, make sure you use a regulator, not a valve. A regulator limits total pressure, a valve would limit the volume of air but still allow high pressure to build up eventually.

DIS says to use 2 bar pressure (~30 psi), exceeding that can damage components I would imagine.

Just buy a Motive pressure bleeder and you'll be fine bleeding brakes as long as you keep fluid in the pressure bleeder.

Also, Ashaman, try activating ABS in some deserted parking lot (wet or sand/gravel help). That'll shake things up good in the ABS module. I like to do this from time to time to keep the system 'fresh' and it is fun.

Good luck!

Brakes
 

Did a complete pad and rotor swap. When pushing in the caliper piston, I opened the bleed screws to let the fluid out that way. Did a pressure bleed and ran clean fluid through - no pedal pumping, reservoir never ran dry, no line was ever cracked. Pedal is mushy with engine off, but gets to a firm spot (standing on it with both feet and all I can leverage). With engine on and some level of consistent force on the pedal, it sinks slowly to the floor. I have seen all the posts and it looks like a thorough bleed with the software is in order, but I am at a loss to actually explain what has happened.

Any insight from the experts? This is messed.

Thanks.

Go in a parking lot and slam the brakes to activate ABS once or twice. That should run fluid through the module good. Then bleed again if needed

If you never let the fluid level drop; it doesn't seem like there should have been an issue as there wouldn't be an opportunity to introduce air into the system.

Opening the bleeders to allow the caliper to retract is always a good idea - shouldn't have caused an issue either. :dunno:

Other than cycling the ABS unit I am not sure what else to try.

Only thing I can think is there are two sections in the reservoir. Maybe I was watching the level, but the rear section I didn't see and it ran dry. I had a pressure bleeder with lots of fluid connected and it never ran empty. One bleed already with the software and no luck. Pedal still sinks with engine on, mush, but doesn't sink with engine off.

Uh oh...that is exactly what I did. I hate to say it, but I think you are in the same situation. Bleed cycle pump bleed cycle pump, repeat many, many times :(

Hi Ashaman - to clarify, did you let half the reservoir go empty as I suspect I may have? Or just the symptoms are the same? Approximately how many cycles were required to fix?

I still can't see how it went empty, because the fluid I was flushing out was a different colour than the new stuff. I ran a lot through and it all came out clean. Unless I introduced a large air pocket right at the end of it.

No good explanation for how it's operating on vs off though. No one I talk to can explain why it is like it is.

Thanks.

Yes, I let it go empty accidentally. It sounds similar. The pedal was really weird feeling; sometimes almost "fluttery", but when it built resistance it would creep down to the floor. If I had not known the history, I would have suspected a bad master cylinder.

I had to cycle it LIKE FREAKIN' CRAZY. Seriously, I just kept running a circle doing one wheel at a time. About the time I thought I wasn't getting anywhere a huge stream of bubble came out of the passenger's right, and it was all improvement from there. I drove it around for a day or two, then did another go around just for the heck of it, brakes are amazing now.

I really used all methods included in this thread; pumping/releasing with the engine on and with it off. Pressing the pedal to the floor, opening a bleeder with the tube submerged in fluid, releasing; Pumping with it open and submerged. Couldn't really tell you which if any of those helped, but the the cycling under pressure seemed to really be the key. Lots and LOTS of cycling under pressure. Well, that and a truckload of persistence; beyond what I thought was reasonable :)

After reading this thread I wanted to make sure I avoided introducing air into the system (I flushed my brakes last weekend)

I did one caliper at a time and disconnected the pressure bleeder and filled the reservoir back-up between each! :)


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I did a gravity bleed on mine. No issues. I did keep the fluid topped the brim throughout though.

The right rear took forever since that is the one I used to drain the res.

Garrett I think that's the ticket. I think the pressure bleeder I'm using is part the culprit (Motiv). When I get it back, I'll try using it to pressurize only, not pressurize AND fill. So what I'll do is fill reservoir full, then pressurize, then bleed a corner, release pressure, fill, add pressure, bleed - and repeat until that corner is good. I won't rely on the bleeder to maintain the level as I suspect it introduces bubbles when you fill it with fluid and/or pressurize it.

My own experience says you are correct. Use just the tank for pressure only, filling up the reservoir each time and you will be fine. I have used this procedure on approx five BMW models now and all end up perfect.
The right rear (passenger rear) has the longest run from the reservoir so take your time, bleed it completely as the fluid has to run through the master, ABS system, down the entire tube lines to the caliper. The dirt, scale, and dis colored fluid will make you think you taped into a used oil drum some where, but don't worry it will clear out after awhile. Just keep the pressure to approx 20 psi, reservoir filled and you will be ok.
I use the foot pedal method at the end to confirm all is functional and to release any "locked" air bubbles in the system. It requires a helper who can follow simple instructions.:confused:

Plan on every two years and you should be ok unless you introduce water or race the X.
Good luck and keep the wheels right side up

It's recommended that the res be pumped out/turkey bastered. If the res fluid is old/wet you dont want to push it thru the system.

The entire purpose of brake system flushing is keeping moisture exposure to a minimum.

I do that. I clear out as much as I can and fill with new fluid. I agree - why push through stuff you know isn't fresh. Just makes it all go a lot longer :)

Is that not the same two year old fluid that is presently in the entire system? I figured it was fine being in there for two years and would be fine being dripped out of the right rear caliper. It dripped about half of quart of clear fluid so I could be sure.

All the brake fliud should be flushed out. By removing all the liquid in the Reservoir first, than fill with new fluid, you will speed up your job as you do not have to "push" all of that fliud through the system before refilling the master reservoir with new clean fluid (no mositure) or discoloration.

Using a pressure bleeder pump makes the job easy as you get to flow a lot more liquid at one time than the older "foot on the brakes - pump it" method. Besides you avoid the chance of tearing up the master cylinder pump seals by pushing too far down the bore into the ruff and possible scaled area where the rubber mater cyl pump seals will get damaged.

Flush every two years and you will avoid a LOT of brake issues especially mosture damage to calipers and lines. :thumbup:

I'm sorry, but the Motiv isn't the problem.

I've bled gallons of brake fluid over my 2 decades of track experience (HPDEs and a decade of racing where I bled before the race weekends and during the race weekends...). I've used a Motiv brake bleed for most of that time on a variety of cars (BMW) and trucks (Ford, Chevy). I've never had a problem with brakes being soft that was caused by the Motiv.

If you are introducing air into the system with the Motiv, you are doing something terribly wrong or I've been the luckiest person on the planet. My sample size in performing this operation is statistically significant. No small sample sizes here...

BTW: when you change brake pads, don't push the piston into the cylinder on the brake caliper without first opening up the bleeder. You don't want to push the crap that settles out in your caliper back up into the brake system.

BTW2: Use a small metal object to 'tap' the caliper as your are bleeding the brakes (I use the handle of a small ratchet wrench). That'll help release any stubborn air bubbles that are sticking to the caliper due to surface tension.

BTW3: Glad the brake problems of the folks in the thread have been solved!

Jury still out for me on the Motiv. But your experience is similar to the tons of others who post videos and swear by it. Now, the one i have may be very old, but it hold pressure. When I pump it up, I can hear it bubbling through the fluid. Last time I did my brother-in-law's car and we shone a light in the reservoir after removing the bleeder, it was full of micro bubbles. And his brakes went to crap. But I'll keep trying to find a way through with the pressure bleeding technique. I'm going to the shop tomorrow to try a pressure and vacuum bleed at the same time. I'll post results. I too find it hard to believe that many use the bleeder without issues.

For BTW: This is what I do - open the bleed screw, not letting the crud back up.
For BTW2: I use a dead blow hammer. Easier on the ears, same result.
For BTW3: I wish I was in this camp now. I'm not, but I most definitely will be :)

Cheers.

The res fluid will usually have more moisture then the ABS module/line fluid, due to the res cap allowing more moisture absorption from the atmosphere.

The indy shop tried pressure, pedal and vacuum bleeding without success. I've suggested the following:
- bench bleed master
- use GT1 to block off the ABS channels and see if issue(s) lie in master/abs circuits or in one of the channels somewhere after the abs
- bleed with vehicle running
- crack fittings at master and abs while bleeding under pressure

Any other ideas? What kills me is it had a good pedal, I tossed on new pads rotors, backed out pistons with bleed screws open not forcing up fluid and then pressure bled fresh fluid through the system (no pedal presses, just pressure and let it run through until clean). Pedal is mushy but stops when off and mushy but goes slowly to floor with medium, consistent pressure when vehicle on. It does still stop, because I had it out to bed in pads/rotors. I'm baffled as is the shop - and these guys have done nothing but BMWs for the last 25yrs.

The shop is also going to swap in a master they have and see if that does anything. Could have just freed up some gunk when I pressure bled it and messed up the seals. I'll keep everyone posted. If I ever get it working, I'll report findings and never touch the bloody brakes again :)

This is absolutely nuts. I can't believe the amount of issues a simple brake bleed seems to cause people.

I need to bleed my brakes desperately, but this seems to make me nervous. I need to get my laptop back to working order and fire up the GT1. I think the fail you guys experienced is by not doing this correctly from the start.

It isn't just reserved to us X53ers either. I've done some searching and it plagues more people than you can imagine. Now, I'm not an idiot, but I really can't see what I did wrong and a shop who has been doing this for 25yrs can't seem to fix it or explain it either. It's nuts, I agree. It should be as easy as this video below, but alas the Germans and their complex ABS/DSC/whatever-else systems tend to complicate things a bit. I laughed when I watched this video. Can you imagine doing the X5 master like this and it working?
Fixing A Sinking Brake Pedal


But check out some of these various threads for some head scratching. All over the map.

Porsche issues
Sinking brake pedal - Rennlist Discussion Forums

More pedal sinking - pads this time?
Changed the brake pads - now the pedal sinks in

More bmw mysteries
e39 sinking brake pedal

See post #18 and #20. Bloody hell
http://www.xoutpost.com/bmw-sav-foru...s-floor-2.html

See post #2 and the pdf it references - these brake systems are so simple - unreal
Brake Pressure Sensor (DSC/ABS/BRAKE Trifecta) - Bimmerfest - BMW Forums

Well I did a gravity bleed on my 330xi, 545i manual, and the 3.0 e53 x5 and had zero issues. Even my beater Passat 1.8 wagon got a gravity bleed.

Until I understand why people using bleeders are having these problemsr this is how I will do my brakes. It does take longer but you get a feel for how fast it is dripping on and you can check in on it every ten or fifteen minutes to keep the res topped off. I don't let it get much lower than the max line while doing this.

If you have an air compressor, then make your own cap (Volvo ATE Cap).

And as mentioned above, never allow the reservoir to go empty during bleeding.

I wrote the detailed procedure for my E39 (1998 528i) below:


DIY: 1-man Hydraulic Bleeding Kit for those with Air Compressor!
DIY: 1-man Hydraulic Bleeding Kit for those with Air Compressor! - Bimmerfest - BMW Forums

Should say HACK mechanic for 43 yrs!

If a mechanic pulled my master cyl without first covering the surrounding area with plastic/shop towels I would give him a boot to the shorts!

Brake fluid strips paint off metal.

Doing a DIY vid for noobs needs proper info, like information about torque wrench use (for noobs who think "if I can still turn it, it not tight enough").

Given the condition of the interior (torn seat, exposed foam) I kinda doubt it if the exterior is in any better shape.

Mechanic for 43 years because people are too cheap to bring it in to a ASE mechanic.

There's NEVER an excuse to give a customers vehicle back in worse condition (paint stripped sheet metal, too cheap to use a 10c plastic sheet).

I wonder how many new DIYers stripped master cyl studs/cracked castings from over-torquing.

Hack DIYING is easy, totally desregards the details, that's where the devil is.

I laughed at that video - it was classic.

An update for those following:
The indy shop swapped in another master and re-bled. Same issues remain. He has a BMW tech from the dealer over to assess as it had the whole shop scratching their heads. The tech said the shop has done everything the dealer would have done and then some. Apparently there is a line that they feel could have air trapped. Older or newer models (I can't recall which he said) had a bleed section or fitting in that line (I looked at several X5 versions on realoem and couldn't find one that had one, but those diagrams aren't always exactly what you see under the hood). Next week , he's going to insert a fitting to bleed and have a go at it again.

The saga continues. I'll keep updating as I know. Good thing I have a back-up set of wheels……

Cheers.

Well, get your popcorn out.

A quick recap - I did new pads (OE) and rotors (ECS cross drilled/slotted), pumped clean fluid through with a pressure bleeder. Pedal was mushy, and with vehicle on and pressure on pedal, would sink to the floor. I had to take the car in to get them to do some PITA bushings and the coolant tank that exploded, so I had the indy shop look at the brakes too.

These guys have done BMWs for the past 25 years or so. They did everything - pressure, vacuum, pedal, replaced master, software and every combination of the latter. Pedal still sunk very slowly. This was a "fit it in when you have time" kind of arrangement, so it took 4 weeks to go through all this (plus the bushings, suspension and other stuff).

It really had the guys baffled. They brought in guys from the dealer and no other insight. Here's the head scratcher - they proceeded to do the "vehicle on, pedal test" with any X5 that graced the shop over the 4 weeks. They found the same thing with 5 others. When I picked mine up, I tested the pedal on a 4.8 that just pulled in and another 4.4 - same bloody thing. I can't explain the voodoo magic, but they feel ok (not as solid as before I did all this), so we'll see how they bed in and test out over the next few weeks.

So, to prove this whole mess wrong, go out, fire yours up, apply moderate to firm pressure on the pedal and see if she slowly starts to drift down. It is farther than normal braking, so I don't notice an issue when driving, just when parked and doing this. I'd be interested to see how many experience the same. I did read this on another thread somewhere, and couldn't believe it, but I sat in two others and the mechanic did the same. Head scratcher for sure.

Cheers.

Wow, my ass crack is sweating.

6 pages and no fix?

I made the mistake of thinking replacing the brake booster (which requires removal and drainage of the mcyl etc) would be straightforward. There is no way to get away from this job without introducing at least some air into the circuit. I thought with the right software (I have both INPA and ISTA) this would be trivial. Boy was I wrong.

After spending a week trying to bleed with 2-man pedal method and getting nowhere (pedal goes RIGHT to floor, virtually no resistance) I sprang for a Schwaben pressure bleeder. Almost right away I got a ton of air (kinda like frothy brake fluid) out of the front right and front left lines, and pedal feel improved considerably. Some air came out of the rears but not much.

Its fairly hard with the car off, but as soon as I start the car (and the vacuum assist kicks in) the pedal sinks almost to the floor. For the first 80% of the travel of the brake pedal, I have NO BRAKES. Then at 85% or so, car starts to slow, and if I press it to 90-95% of travel the brakes will lock. So the brakes work, just not for the first 80-85% of pedal travel!

I am fortunate to have a gravel driveway so I pulled some serious hard brake skids, went back and bled it. Not much (if any) air comes out; pedal is like mush.

Pulling my hair out - where to from here??? I see a couple of you have been to the dealer who couldn't figure this out either!!

You got air between the abs pump and the brake system. Under normal condition, the ABS pump is not a factor in braking, it is only when one of the wheel sensors signal the ABS computer that it is not in synch with the other wheel sensors, that is when the ABS computer instruct the ABS pump to start pulsing the wheel that is not in synch with the other wheel (Normally a wheel is out of synch when it locks up). That is why to use the ABS system you need to stand on the brake so that the system can work.

You will need to get a scanner that that can auto bleed the ABS module.

Here a video on using an auto bleed scanner. Note that when he auto bleed the module he has his foot to the floor on the brake pedal. Are you guy doing this with INPA?

https://www.youtube.com/watch?v=fUqmBqYIEAE

Right but if I use the ISTA-D software service functions to run the bleeding routine won't the system cycle the ABS/DSC pumps for me to let me bleed these components as well?

Here's what it looks like in the software:

When you auto bleed are you putting the brake pedal to the floor?

No because the on-screen instructions say not to do that - it says:

1. Connect & pressurize bleeding equipment (which I presume is a pressure bleeder to the reservoir)
2. Open bleed screw
3. Run the "bleeding routine"
4. Actuate the brake pedal to limit 5 times - clear fluid should escape from the bleeder
5. Close the bleed screw

I follow those instructions to a T - no improvement after nearly 3 bleed cycles and over 2 liters of fluid bled through.

This is how I used INPA to bleed the ABS module.

Open INPA.
Select E53
Select Chassis
Select appropriate DSC
Select Activate (F6)
Have second person put pressure on brake pedal
Select either F2 or F3 (ABS FL RL or FR RR) depending on which one you are bleeding
When you hear the ABS buzz, open the bleed valve. It will then make a second noise where is activates the valves at which point the pedal will start going down in pulses and the fluid will start coming out the caliper.

upallnight, when I hit "F6" to activate - my INPA doesn't seem to have those bleed methods.

However here is what the ISTA bleed screen looks like

for the bleeder container do you have a tube/hose that is attached to the caliper bleed nipple and the other end of the tube/hose is below the fluid in the container? If the tube/hose is above the brake fluid that you are collecting in the container when you release the brake pedal after pushing to the floor it will suck back air into the system.

It does, and my bleeding catch bottle has a 1-way check valve in it as well.

I am going to bleed 500 ML of (~15 oz) fluid through each caliper tonight... if that doesn't fix it then I'm not sure.

I never pedal bleed anymore. Uses too much fluid and it is not unusual to have to do it several times to get a solid pedal. When I did pedal bleed I closed the bleeding valve before the pedal got to the floor. Pumped brake pedal up and did the same process over and over. Not unusual to see clear fluid for several cycles and then see more air bubbles.

Since brakes are rather important I think it is imperative to purchase a good quality pressure bleeder and follow the process in the ECS video posted. I have used a vacuum bleeder that was very effective also. I never use the same color fluid when bleeding. Shouldn't have any problems getting the brakes bled in all but the unusual circumstances.

Hmm, unfortunately not making much progress here. I believe the situation has been made worse - of the 2 ports on the master cylinder, the one closest to the front of the vehicle is fine but the one that comes into the side of it has a slight leak. Looks like I just didn't tighten it enough... my fault for not checking this.

I bet there is a shit ton of air inside the system now. I tightened down the brake pipe (Had to really go to town on it to get it to stop leaking). Hopefully this hasn't introduced too much more air into the system (since the reservoir has been pressurized to >15 PSI for the duration of this exercise

Can someone outline the EXACT steps that they are using when bleeding.

Here's what I've been doing:

1. Fill fluid + attach pressure bleeder to reservoir cap
2. Pump up the pressure bleeder to at least 15 PSI
3. Attach length of clear hose to the bleeder nipple valve & crack it open until I see fluid flow
4. Run the "bleeding routine" in ISTA/D (screenshot above)
5. After the bleeding routine completes, press brake pedal as far down as it'll go 5 times
6. Repeat steps 4 & 5 until roughly 2-300 mL (10 oz) of fluid emerges from the caliper

The sequence of bleeding is like so:

• Rear Right
• Rear Left
• Front Right
• Front Left

Does that look right?

If yes, how many times should I expect to repeat on each corner before I notice an improvement?

YES! :thumbup:
The sequence of bleeding is like so:
Rear Right
Rear Left
Front Right
Front Left[/I][/B]

Question: Is your vehicle right hand drive and is the master on the left or right? In the US the master is on the left (Driver's side)

Normally it takes 5X to get a great flow and all the air out. I personally do the power bleeding sequence then go back and do a manual bleed AFTER wards, using 80-90% pedal travel as some of the master cyl pistons will cross a water pock section of the bore and tear the piston cup edges. Once that happens you will never get a normal pressure stroke out of the master, forcing a master cyl replacement procedure.

Note: Smack each caliper with a SOFT faced hammer between bleeds as crap gets trapped in their as well. Due to the extra small brake lines and connectors, it takes a while to get clean flow all the way to the right rear as you are flushing the entire system line to that point.

Once the ABS system has air it will take more than a few approaches to clear out. Multiple people have posted that they actually had to drive and activate ABS involvement twice then go back and bleed again to clear all the air from the system.

Good luck.

Going though this nightmare now..
Had to replace a rotted out line to the passenger rear..
Have bleed the rear brakes multiple times..
Fresh new fluid coming out..
Pedal is like a marshmallow..

Guess I will have to locate and try a pressure bleeder next..

The dealership will do a brake system flush for ~$149. At least that's what I was quoted for the 4.8is. I'm sure an indy would be even less expensive. I did my last bleed myself when I removed the rear calipers but had no problems with the bleed. If I was to have the problems as some of you describe... the dealer would be a real option for me... and I hate to give the dealer money if I can avoid it.

Just a thought though, I know it doesn't help with the frustrations. :dunno::(

Master cylinder is on the front right of the car.

The ABS/DSC block is on the front left of the car (under the power steering reservoir).

Does this change the bleeding order?

Gotcha, but I'm not trying to save money here (I wouldn't have bought a 4.8L V8 in a country where fuel prices are pushing $1.53 AUD per LITRE). I want to be self sufficient here - I've tackled several more difficult jobs and this simple one has me by the balls!

The ABS needs recycling to open the valve using the proper software as the rears have most likely bled out. That's the issue I had many years ago when I fitted my BBK.

Understood. I didn't notice you were in Oz. Keep soldiering on and I wish you luck. :thumbup:

Hmmm, I hope that is not the case, I guess that means a trip to the dealer, trying to avoid that.

I don't believe the Master Cylinder ever went dry, so trying to wrap my head around how I'd have gotten air into the ABS pump..

Going to go through and bleed everything again tonight and see what happens.
Worst that can happen is I'm out another bottle of fluid I guess...

Ok if it didn’t run dry then should be ok but just does sound like it when you have fluid going through no issues when bleeding but no pedal.

A good Indy could do it for cheaper I’d have thought if you do have to go that route.

Why don’t you guys jusr invest in a $20 Chinese diagnosis cable. It even comes with INPA. You just need a laptop to load it on.

Any suggestions/links on cables and software that have worked well for members?

Bleeding order is to start from the wheel that is furthest from the master cylinder and then the next furthest, etc.

It would appear my problem is not to do with bleeding at all but rather a leak from the rear port on the master cylinder.

Does this look like it's "in" all the way to you guys? I am reluctant to keep tightening it. I don't have a torque wrench that can go on a fitting like this.

BMW TIS says this fitting "Brake lines to hydraulic control unit" should be 17 nM
https://www.newtis.info/tisv2/a/en/e...-lines/5eAqjtl

I don't really think I can tighten this thing anymore...

Hard to say if the connection is tight or not. Meeting torque specs is the determination though if it is cross treaded torque specs will not be accurate. Did you remove this line or were the symptoms prior to the brake work similar to what you have now? Be sure to use a brake/fuel line wrench.

I don’t believe it’s cross threaded. I used my fingers to do it until it was almost all the way in then used my 12mm open-ended spanner. I did remove this line, it’s not possible to extract the brake booster (which was the point of the exercise originally) with this line (and the master cylinder) in place.

I bleed another container of fluid through it this weekend. Took it to a local parking lot. Pedal still like a marshmallow, but if you pressed deep down, it would stop the car..

Did a bunch of panic stopps, getting the ABS pump going. But it just seemed like the rear brakes were not engaging at all..

Well, broke down and took it to the dealer this morning. Explained that I though there was air trapped in the ABS Pump and needed them to have the computer run the bleed sequence to get it out..

Hour and half later they brought it around. $143 dollars sir..

Drove it, somewhat, but not alot better than it was..
Went back in, asked if they test drove it..
Service advisor drove it, said felt fine to him..
Asked if they had cycled the ABS pump, he had no idea of course..
Took it to the shop foreman..

Another hour and half later, Advisor tells me they ran the 'bleed program' from the computer and asks me to test drive it..

Light years better. I'm still a little unhappy with the pedal feel overall, but at least all the brakes are working, and it is safe to drive again.

Hoping my experience is like "Ashaman", in that I've got a solid pedal engine off, but soft engine on

Thanks everyone for your feedback..

P.S. - Would be nice if you didn't have to tell the dealership that there is a procedure to run on the computer to get the air out of the ABS pump..

From the picture that you posted it looks as though it is cross-threaded. I changed the spark plug on my second Lotus and I threaded it in by hand, but when I tried to tighten up the plug with a wrench I felt that something was not right. Yup, you guess it I cross threaded the spark plug hole. Lucky for me I had a spare head that I install to fix the problem that I created.

ABS BLEEDING ISSUE
 

It appears in my research that the ABS can have air bubbles which are difficult to evacuate, been through three bleeding procedures and cannot get full braking, worse yet, brakes lock up when hot at precisely same point in daily drive. Pressure bleed, but very little air came out at calipers. Unlocked the proportion valve which was preventing rear brake bleed as the brake line ruptured and had them replaced. So this is where my problem started, got stuck taking it to a independent who supposedly knew BMW's, yes he came back and said I need master cylinder when he could not bleed rears, and he had no diagnostic system evidently. So got screwed, took it home on front brakes only, replaced master cylinder and no difference, which led me to researching issue myself, bought the bleeder diagnostics, got to bleed rears, but using vacuum bleeder was not working, bought pressure bleeder, got more air out, but still same issue of soft peddle and only 50% braking and still locking up. I read that jacking up rear is solution for stuck air bubbles in master cylinder, so I am stumped, will try to bleed again. Any suggestions?

Thanks,

Great info, thanks.

There's a specific order on bleeding and you must activate the ABS while doing it or else you basically are just pushing bubbles back and forth in the block.

Believe it's RR, LR, RF, LF but I don't have it in front of me to verify. Sorry

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I learned this the hard way after replacing a rusted out line to the back. It never dawned on me, as I read through all the threads and reviewed ISTA/D on procedures until I broke down and took it to the dealer. It may be self evident but I didn't think of it in trying to do this single handed. I asked the dealer and they have 2 people bleeding the brakes. IIRC, one pumping the brakes while the ABS is engaged via ISTA and one cracking the bleeder screw open.


I bought a pressure bleeder thinking that I would be able to do this by myself AND while activating ABS. No such luck. I had the steps right, starting at the right rear wheel, but it is a 2 man job.

If there's any DIY I just can't stand doing it's brake bleeding - so f#$@g bloody tedious but must be done right, or else .... So, for $120 done at my local dealership, I call it money-well-spent for such an onerous task.

Agreed, but sadly I just had mine done but they only used a pressure bleeder and no software to activate ABS module they said. Ugh.

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What, at a BMW dealership? Surprising. Any way, next time make sure they know that you know the procedure;). Have a little friendly chat with the shop foreman.

I actually had to take mine back a second time as there was a disconnect between what the person in service heard me say I needed done and what he told the shop needed to be done.


Somewhere somebody 'thought' they heard me say I wanted my brake fluid flushed. Not bled... That word never came out of my mouth.

You are correct as to bleeding process, always bleed brakes from furtherest caliper than next closest etc.

Brake line length then, correct?

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Yes, longest to shortest brake line which is as was posted.

Thanks. The reason I wasn't sure was because of the ABS block and whether it was a difference because of it.[emoji106]

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Well, this Indy mech (shop owner) is a veteran from BMW who left them and started his very own (very successful) shop and has lots of ex BMW mechs now too. I just brought back by and the owner, who I've dealt with for 15 years now, felt the pedal and right away said it was buggered and wanted to fix right then and there. I LOVE their service and they always treat me and my Bimmers very well. I talked with him about the ABS and GT1/INPA software and he said you should never have to use it for a simple bleed or when you change your calipers quickly, as I did. He fully knows of the software but said it was no way warranted for this bleed. BUT now that he felt the bad pedal, I'm not sure of his plans for it today.
Find out soon :)

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I have never had to bed the ABS. I use a pressure bleeder which makes it painless.
When possible I like to change color fluid so I can easily tell when only new fluid is coming out.

I only had to do this when I replaced the brake lines from front to back. Outside of that I have never had to either.


Who here still has Ate Super Blue left? I only have one unopened can.

Doesn't flashing the brake fluid require exercising the ABS? Aren't we supposed to renew the fluid every 2 or so years due to the hygroscopic properties of the fluid and also given the fact that the brake fluid in the ABS system mixes with the rest of the brake fluid flow circuit when the ABS is engaged during panic stops?

A full flush should require you to need to bleed the ABS, in that case. Yes.

Oh a side note, my mech managed to get my soft brake pedal perfect again. I didn't find out how sadly. I will next time I go in.
Just glad to have it done safely.

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