Odd Brake Issue

[CapeX5]

Hello All,
05 4.4. Just had 2 rear brake lines that rusted out and I replaced them. Car was operating perfectly before rusted out lines. There was a delay in getting parts and the reservoir leaked all the fluid out. I filled, did a Motiv pressure bleed. Was getting minimal fluid out of rear caliper bleeders. Hooked up my Foxwell and found the brake bleed procedure. Did this numerous times on all wheels. Fronts had plenty of fluid coming out, rears had minimal, with some air. Still not getting brake pressure to the rears. Started disconnecting lines at the ABS module and front circuit was flowing fine, rear very slowly. Figured I messed up the master cylinder. Replaced it. Same situation with fluid flow/quantity to the rears. Took old master apart and realize that the rears won't bleed with pressure in the front brake circuit of the master. I decided to have someone put pressure on the brake pedal, bleed fronts, than with pedal still down, open the rear bleeders and get air and plenty of fluid out. Almost like all 4 need to be bled simultaneously. I have searched everywhere and plenty of posts on the rear brakes being a problem, but no solutions. Now, I can't access the ABS module on my Foxwell and the pedal is super hard. Took for a test drive and the brakes started to seize up and I had to release the pressure at the ABS module where the 4 lines come out of the top to each wheel to release the calipers. I do have INPA and tried to access the ABS/DSC module but could not find it.
I am so sick of this car and how complicated it is. I would appreciate any help or suggestions sorry for the length of this but thought all information was pertinent.

[80stech]

Try releasing the pressure at the master cylinder instead of at the ABS controller. It's possible that you have a bad master or that the pedal/rod is not allowing the piston all the way back.

[cn90]

- If the brake system worked BEFORE the repair, then the issues you have now are related to the repair job.

- I wrote a DIY for brake lines (in forum if you search for it), the key thing is to use a wood stick and partially depress the brake pedal to stop the fluid loss.

- Now you have air in system. I don't know much about Foxwell since I use INPA.
You can put everything back together and use Foxwell etc. to activate the ABS valves to bleed...

[andrewwynn]

The symptoms match a booster set too tight. A not that uncommon error when changing a MC. I've seen it 3 times in the past 2 years on XO. I don't know the procedure on e53 to adjust but found on YouTube for a buddy with his f150

[Moments]

My E53 burst a line while away from home and needed a repair. The change of the line was easy for the mechanic but the bleeding was a real problem after the fluid loss - which to my untrained eye looked pretty substantial. It took a few people and a lot of time and fluid to get the pedal back to where it had been. I would imagine that the a part of the problem here is air working its way back to the ABS unit and being very stubborn to clear.

[Effduration]

Originally Posted by cn90

- If the brake system worked BEFORE the repair, then the issues you have now are related to the repair job.

- I wrote a DIY for brake lines (in forum if you search for it), the key thing is to use a wood stick and partially depress the brake pedal to stop the fluid loss.

- Now you have air in system. I don't know much about Foxwell since I use INPA.
You can put everything back together and use Foxwell etc. to activate the ABS valves to bleed...

+1 on this....

I don't think there is a problem with your ABS module or master cylinder. The E53's are just difficult to bleed. I had a similar issue with mine when I replaced a portion of brake lines.

I would hook everything back up and bleed again.
Look up instructions on how to use INPA or foxwell to bleed the ABS pump.
then use BOTH the pressure bleed and the two-man method.

Hook up the pressure bleeder while a friend pumps the brake and you open/close the bleed screw.

As you noted, the front/back balancing valve will limit how much fluid comes out the back, so you have to open and close multiple times.

[CapeX5]

Thanks for all the replies, it is helpful. I have continued to bleed it and now I get the fronts that seem to be binding on when they get hot. To the point of setting off the "4X4 INACTIV" and the DSC code being thrown. The only way to get it to unlock the fronts is to release the front circuit at the MC. I am running out of helpers and ideas on what else to do. It is becoming a real issue due to it being my main mode of transportation. There is hardly and play in the pedal and it is hard as a rock.

[CapeX5]

I have INPA and tried to find the menu to do the bleeding there. I found a video for a 330 that explained how he did it. E53, chassis, abs/dsc module, Activate....nothing for brake bleeding. Any thoughts?

Originally Posted by cn90

- If the brake system worked BEFORE the repair, then the issues you have now are related to the repair job.

- I wrote a DIY for brake lines (in forum if you search for it), the key thing is to use a wood stick and partially depress the brake pedal to stop the fluid loss.

- Now you have air in system. I don't know much about Foxwell since I use INPA.
You can put everything back together and use Foxwell etc. to activate the ABS valves to bleed...

[CapeX5]

A follow up to close this thread out. I found very little definitive information on the common rear brake line bleeding issue. I finally got this resolved but it took HOURS!!! I did the following 3 things. Moved the coolant reservoir out of the way to access the top of the ABS pump. Used my Foxwell to activate the pump while loosening each 4 lines a little one at a time and bled whatever air was in there out. All the while I had my pressure bleeder connected to reservoir on master cylinder with 20lbs of pressure. Once I new the air was out of the master and ABS pump I moved to the rear lines. There was no way to be sure all air was out of the above procedure, but I must have done the procedure 5-6 times. At the RR wheel I hooked up a clear hose and bottle to monitor the air coming out of the line. Open the bleeder and you will see a very slow trickle of fluid coming out via gravity/pressure from the pressure bleeder. I activated the ABS pump via the Foxwell 3 times. Than I would do a slow pump on the brake pedal 6 times. All the while monitor the fluid in reservoir so you don't run out. I did the same on the LR wheel. This process was painful slow and I was really wondering whether I had another problem or ???. So many small bubbles kept coming out I never thought it would end. This literally took me probably 10 hours with different interations of bleeding everything. Feel free to reach out if you have any questions. I also replaced the master cylinder thinking that was the issue.....it wasn't! But I now know how to do that. Good luck.

[Magister88]

Originally Posted by CapeX5

A follow up to close this thread out. I found very little definitive information on the common rear brake line bleeding issue. I finally got this resolved but it took HOURS!!! I did the following 3 things. Moved the coolant reservoir out of the way to access the top of the ABS pump. Used my Foxwell to activate the pump while loosening each 4 lines a little one at a time and bled whatever air was in there out. All the while I had my pressure bleeder connected to reservoir on master cylinder with 20lbs of pressure. Once I new the air was out of the master and ABS pump I moved to the rear lines. There was no way to be sure all air was out of the above procedure, but I must have done the procedure 5-6 times. At the RR wheel I hooked up a clear hose and bottle to monitor the air coming out of the line. Open the bleeder and you will see a very slow trickle of fluid coming out via gravity/pressure from the pressure bleeder. I activated the ABS pump via the Foxwell 3 times. Than I would do a slow pump on the brake pedal 6 times. All the while monitor the fluid in reservoir so you don't run out. I did the same on the LR wheel. This process was painful slow and I was really wondering whether I had another problem or ???. So many small bubbles kept coming out I never thought it would end. This literally took me probably 10 hours with different interations of bleeding everything. Feel free to reach out if you have any questions. I also replaced the master cylinder thinking that was the issue.....it wasn't! But I now know how to do that. Good luck.

This is very different experience from mine, my rear right line rusted out at the union where it crosses to the right rear side. Lost all the brake fluid in the reservoir as I was driving the car. After replacing the lines, i added the brake fluid, and used the pressure bleeder as well. using a scan tool i cycled the ABS pump 3x for each wheel while there was pressure applied to reservoir (most air came out from RR). and had good flow. took about 1.5 hrs to bleed all 4. and the pedal feels great. I wonder why it happened to you this way . i do have 3.0i 2004 x5. Anyway good you got it done!