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-   -   parking brake weird problem! (http://www.bimmerfest.com/forums/showthread.php?t=656633)

mokh 11-06-2012 11:45 PM

parking brake weird problem!
 
hey all

i've been having this weird problem with my parking break. If any of you have taken apart the parking break unit in the boot, you should see a plastic gear that is spun by the motor that tightens and releases the parking break. Something went weird with that plastic gear and it got shattered.....anyways to make a long story short, i replaced it and now my parking break works, only when the ignition is on! The autopark feature works and if I engage the break when in neutral it stops the car, but when I turn off the car it disengages the break, engages Park on the transmission and holds the car on the Park gear. Its not really that much of a problem if I'm parked on a level road but when parked on an incline I've heard that it could damage the gears in the transmission. I reset the values in Inpa for the parking break and plaued around with the tension values but with no sucess. The car still disengages the parking break when I turn it off. What do you think would be the problem? I've had my parking break tuned by removing a lug nut in the rear wheels (left and right) and adjusting the gears manually (just like the instructions in TIS) but that also didnt have any effect. Does anyone have the correct values for the parking break in Inpa? could there be a loose connection somewhere?

thank you.

Sent from my GT-P6800 using Bimmer App

alpinaman24 11-08-2012 12:28 PM

did you use a scanner to re align the "tight" and "loose" position

ive replaced just the inner gear with the kit from odo gears .. but before i touched it i went into the emf module and put the module in "assembly" mode

bobbrum 11-08-2012 06:21 PM

My gears were destroyed this past Monday and will be getting my new gears from Odo Gears. I am interested in avoiding the same problem after making the fix.

mokh 11-09-2012 02:27 PM

Quote:

Originally Posted by alpinaman24 (Post 7184042)
did you use a scanner to re align the "tight" and "loose" position

ive replaced just the inner gear with the kit from odo gears .. but before i touched it i went into the emf module and put the module in "assembly" mode

THAT....i didnt do. i dont know how to re align the tight and loose positions since i dont know what values to input. i'm assuming u used inpa? also, i didnt put the module into assembly mode...i didnt know i had to :s

what can i do now?

rippjd 11-11-2012 02:37 PM

Quote:

Originally Posted by mokh (Post 7180655)
The autopark feature works and if I engage the break when in neutral it stops the car, but when I turn off the car it disengages the break, engages Park on the transmission and holds the car on the Park gear. Its not really that much of a problem if I'm parked on a level road but when parked on an incline I've heard that it could damage the gears in the transmission.

I have the same issue with my E65. I took the access cover off the parking brake module and my gears are in great shape. I did redistribute some of the grease as I was in there...
Actuating the parking brake with the engine off I see the cams rotate and put tension on the left and right cable until the motor is "bogged" down to the point of stopping.

I have not followed the procedure in TIS to adjust the parking brake adjustment screw (if I recall correctly tighten all the way, then back off 10 notches) and was hoping that was my issue... but perhaps not.

For those who don't know, actuating the parking brake with the engine running does not use the cable driven shoes. Instead it uses brake fluid to actuate your regular brake pads. Once you turn off the engine the system switches over to the electromechanical parking brake and you loose the brake fluid pressure thereby releasing the regular brake pads.

mokh 11-12-2012 05:43 AM

i did figure out that there has to be 2 mechanisms at work in there. i took apart the actuator unit today and had someone press and release the parking brake. the mechanism travelled up and down freely and everything was in good working order except the brakes were not functioning! even thought the icon on the dashboard lit up the car still rocked when rocked back and forth (i has the ignition in position 1...pressed Start without the brake pedal) I also read the error memory and it had an error in it...something in german that looked like vehicle roll or something. I'm gonna try re-adjusting the sprockets in the wheels and see what happens.

Sent from my GT-P6800 using Bimmer App

alpinaman24 11-12-2012 10:27 AM

i use autologic

i only use inpa and ncs for coding even tho i can code with the autologic its limited to a certain point

but i realign using autologix and that problem goes away

mokh 11-13-2012 02:45 PM

today i adjusted.the sprockets of.my.parking break by turing them all the way to tighten nd then releasing them a couple of notches...still no fix, i'm.getting stumped with this amd running out of ideas. i'm gonna try changing the break pads of the parking break. maybe that would fix it.

alpinaman: i did the autologic reset and alignment. still didnt work :s

stuartjohn24 11-13-2012 03:02 PM

Guys!!!!

Sounds like your cables are stuck/corroded, when the engine is on the car holds itself using the hydraulic brake pressure, when you switch the engine off it switches over to mechanical holding.

Check your park brake cables! I was having issues with mine, this is what I found when I removed mine! :yikes:

http://i886.photobucket.com/albums/a...0BA19F886B.jpg

The cable had corroded and become stuck to the outer cable sheath, this stops the parking brake from actually holding the wheel and in some cases causing stress to the gears like in your case.

http://i886.photobucket.com/albums/a...0C14CBAB99.jpg

This is the new and old cables compared, BMW changed the design, the cuase is the cable outer sheathing rubs on the subframe, this allows water to get inside, rust the outer steel shell causing it to expand and then rub on the inner plastic/PTFE coated inner core wearing it away and then causing that to rust too!

The cables only come as a pair, even though only one of mine was broken the other side was in a very similar condition.

http://i886.photobucket.com/albums/a...0BEA9A7BB6.jpg

Hope this helps, its worth checking! Im sure this puts stress on the park brake module itself if these are seized.

Stuart

alpinaman24 11-13-2012 03:10 PM

ahhhhhh very good john !

stuartjohn24 11-13-2012 03:17 PM

Quote:

Originally Posted by alpinaman24 (Post 7192911)
ahhhhhh very good john !

Well... its Stuart, but thanks! :D

alpinaman24 11-13-2012 03:54 PM

lol you got it Stuart

rippjd 11-16-2012 07:30 PM

2 Attachment(s)
For those who want to read the technical details on the parking brake, attached is the technical training literature.

Besides the cable being seized internally, I suppose it's also possible the mechanism between the top of the parking brake shoes is seized, as this is what the cable pulls on.

mokh 11-17-2012 12:44 AM

Quote:

Originally Posted by rippjd (Post 7199306)
For those who want to read the technical details on the parking brake, attached is the technical training literature.

Besides the cable being seized internally, I suppose it's also possible the mechanism between the top of the parking brake shoes is seized, as this is what the cable pulls on.

great literature! thanks for that :)

incidentally, my parking break works fine now! I have no idea how that happened though! all I got was an error message on the dashboard after tightening the sprockets on the rear wheels, I didnt know what to do so I just cleared the codes using INPA and now the system works just fine, after I let the car sleep overnight! Seems to me it just needed a 'reboot'!

Thank you for all your help and contributions. This community has once again saved me valuable $$ :P


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