[jrf0195]

Hello all. First time Bimmer owner with brake questions. Bought the car about 6 months ago. Everything has been fine with the braking up to this point. Last week the brake light came on so I decided to replace all pads and rotors this weekend. I am no stranger to this kind of work and everything went well as far as the installation goes. Put it all back together to take for a test drive and find that once the car is running and in drive I have to push all the way to the floor to brake. The pedal builds up pressure when I pump it a few times, but the next time I brake it goes back to the floor. Instinctively my first thoughts were lots of air in the lines. So I bring it back and begin bleeding the lines. I'm using a vacuum bleeder at the nipple, not the pressurized one at the MC. Bled all 4 sides in the suggested order (per other posts in the forum) take it out for a spin and the same thing. I have combed through the forum for similar things but they seem to generate more questions than answers for me, so I'll start with those.

1) Some of the other posts refer to air in the ABS and that it needs to be bled. However, all those posts seem to be for much older vehicles. I was very careful to make sure I didn't let the MC go dry, so how would air get into the ABS?

2) I have spent no less than 2 hours on the RR wheel alone with the vacuum hose running. I do not see any "large" bubbles coming from the nipple, but I do see what looks like fizzing bubbles that never seem to stop more than a second or two. Initial thought was perhaps it's normal since no seal, other than hermetic, is perfect so maybe I'm introducing air into the suction from the bleeder being open too far or the hose on the nipple. Adjusting the nipple to as closed as possible and still have flow doesn't make a difference. The hose is as tight a connection as it's going to get. Do I just need to keep at it until even that fizzing stops or is this normal? I also thought maybe there is a small leak in one, or multiple, lines creating this fizzing action as I siphon. But again brakes were working perfectly fine before the replacement.

3) a thread or two mentioned bleeding then driving and stomping on the brake a few times to activate the ABS, bring back and bleed again. I drove around enough to come to complete stops at least 8 times, but I never did the stomping. I've always been under the impression that ABS is active throughout the braking process, not just a quick and sudden braking action. Am I wrong about that and need to do another test drive using that process?

4) If I do need to bleed the ABS system, is there a good source for procedures on that? The threads I came across here were previous gen cars so I'm thinking they wouldn't really apply.

5) Will the brake pad warning light go out on it's one once the pressure is correct and the sensor detects the new pads?


Appreciate any feedback. Hell even good humor at this point. I could use a good laugh.



TIA

-JF

[Billfitz]

The pad warning light goes on when the sensor is worn out. It must be replaced, and then you must manually clear the warning light. Google for youtube videos that show how.

[jrf0195]

Originally Posted by Billfitz

The pad warning light goes on when the sensor is worn out. It must be replaced, and then you must manually clear the warning light. Google for youtube videos that show how.

Thanks. Luckily I went ahead and replaced the sensors while I was in there too. I'll look that up as soon as I get this bleeding issue resolved.

[Orion4]

Sounds like there is still some air in the lines. If you performed just a normal bleed, not letting the reseviour get empty or opened any of the lines, thereby let air into the system then you should have been good. As a FYI, here is a F30 based bleeding process by Brian Kies:

If by chance you did get air into the system, you will probably need to get ISTA to correctly bleed the lines. It has a specific procedure, that removes all the small air bubbles or have a shop do it.

[lpaulodt]

Another way to bleed the abs / esp is to trigger the esp. you will notice that after a few esp interventions the pedal is gonna get firmer.
Air in the brake line is always my excuse to my girlfriend when I’m in holigan mode sliding around 😈

[alohasurftoad]

[g340ix]

use a pressure bleeder, I tried using a handpump vacuum bleeders on another car years ago and never will again. It didn't work at all

[jrf0195]

Originally Posted by Orion4

Sounds like there is still some air in the lines. If you performed just a normal bleed, not letting the reseviour get empty or opened any of the lines, thereby let air into the system then you should have been good. As a FYI, here is a F30 based bleeding process by Brian Kies:

If by chance you did get air into the system, you will probably need to get ISTA to correctly bleed the lines. It has a specific procedure, that removes all the small air bubbles or have a shop do it.

Thanks. I had come across this video and it was my favorite one of them all. If it wasn't for this one I wouldn't have known about the two bleeder valves on the front calipers. I've never seen that before.

I didn't open any part of the system outside of the bleeder valves. So unless I have a leak I don't know how air would get in. I inspected all the lines and there are no signs of leaks or breaks, unless it's a pin sized hole I can't see, but the lines appear normal to me.

I am a little confused about the ISTA tool. Seems that there are 2 and then some people use INFA (?). If I read something right elsewhere correctly I need an ethernet cable for my car. Just haven't found where to plug that in. I'm not sure which tool I need or where to locate it. All the links I have found in the forum are either dead or seriously outdated (with no explanation on the tools and what I need them for). Googling it produced what felt like some sketchy sites to me.

[jrf0195]

Originally Posted by g340ix

use a pressure bleeder, I tried using a handpump vacuum bleeders on another car years ago and never will again. It didn't work at all

@g340ix


I came to this conclusion last night myself. I have literally spent hours and nearly 60 oz of fluid vacuuming a single caliper. I was going to post this morning that I think the pressure method may be the way to go, then I saw your reply confirming that. Shopping for one today in hopes I can get the job done today rather than wait for something to be shipped.

[jrf0195]

alohasurftoad Thanks. I have lots of question about the tool. Do you know of a good thread that lays it out which tool I need, the installation process, etc.?

[alohasurftoad]

Originally Posted by jrf0195

alohasurftoad Thanks. I have lots of question about the tool. Do you know of a good thread that lays it out which tool I need, the installation process, etc.?

what "tool" you are referring to?

[jrf0195]

Originally Posted by alohasurftoad

what "tool" you are referring to?

alohasurftoad

Sorry...ISTA or the equivalents. Seems like there are multiple applications and I haven't been able to figure which are used for what.

[alohasurftoad]

Originally Posted by jrf0195

alohasurftoad Sorry...ISTA or the equivalents. Seems like there are multiple applications and I haven't been able to figure which are used for what.

ISTA+ is a computer program(software) that talks to the DSC through an enet cable going to the OBD jack under dash. It commands vibrating valves where microbubbles are trapped. Not sure if this answers your question...

[g340ix]

Originally Posted by jrf0195

@g340ix


I came to this conclusion last night myself. I have literally spent hours and nearly 60 oz of fluid vacuuming a single caliper. I was going to post this morning that I think the pressure method may be the way to go, then I saw your reply confirming that. Shopping for one today in hopes I can get the job done today rather than wait for something to be shipped.

https://www.fcpeuro.com/products/eur...oducts-mot0109

[Ennoch]

Vacuum bleeders in my experience are not a good way to sort brakes. Pressure bleeders can work well although I still prefer to cycle the pedal when doing it to build pressure and then release it as this seems to work better to get stubborn bubbles out the lines if you're filling from scratch. I found the vacuum bleeders would pull air in from around the hose joint or the nipple threads and lead you to falsely believe that the system still has air in it. You can get around the threads with some PTFE tape but the hose on the nipple is always going to be an issue. One of the other things I've found when bleeding the F30 is that it's got one of the softest pedals of any car I've used. Most have a pretty firm contact point but with the BMW you can almost get it to the stop if you push hard. I'm not sure whether that's lines, booster or ABS block valving, and it feels fine in use (it could always be firmer of course), but it also gives you the impression there's still air in there somewhere even if there isn't.

[jrf0195]

So I agree with the previous comments about vacuum bleeding being inferior. However, that's the only option I had until my pressure bleeder arrives tomorrow. Not that this makes a whole lot of difference, but this isn't the hand pump vacuum. It's one I connect to my air compressor.

Today I decided to try the school method as well as the prime/gravity feed method. Same symptoms occur. With the car on or off the pedal goes down nearly to the floor. It will build up pressure if I pump them but then a few seconds later it does the same thing. My cable finally just came in so I can use the ISTA+ tool. So I am going to use that to try bleeding the ABS module, as suggested before.

I keep going over the lines looking for any signs of damage and leaking and just not finding anything. Then I wondered if maybe I didn't tighten down one of the other bleeder valves enough, but then realized with all the pumping I've done I should see signs of fluid around the other wheels or below them on the ground and I'm not seeing any signs of that either. I'm just dumbfounded at the moment.

[jrf0195]

Finally got my Motiv pressure bleeder in and without any trouble did all 4 wheels in an hour. I am sure there are plenty of people who will swear that they've never had any issues using a vacuum bleeder, but I will NEVER use one again.

On to my next, and more challenging project...valve cover gasket.