SayeedA

My son's 2004 525i was having brake issue - would lockup front left brake and the car would not move. if you let is sit for a while (1-2 hours). Brake will loosen and you can drive again.

he said this was an intermittent problem not all the time

The other day I took for a test drive and the paddle was too soft was touching the floor

I decided to flush the system. I have done this many many times on my 2 other BMW and Land Rover and never had issues, but this time there was no fluid coming out of front left at all. I have a pressure pump I used and after many try no fluid. I had a suspicion that the master Cylinder is gone because it was too soft and paddle was on the floor. We decided to replace the master C and we were able to take each section out and air hosed clean. Brake felt really good after and worked well.

Test drive:

after driving 2 miles Front wheel started to lock up slowly and it finally completely locked up. we let it sit for a while then dove about 2 miles locked up again.
we released the front Nipple fluid shot out and brake released. But it only shot out from front left. Front right did not have that pressure, drove home and started to lock up again.

1. took out each front hose, shot fluid through and compressed Air hosed clean
2. Connected pressure air to sucked out fluid from the metal fuel line between ABS and caliper
3. connected pressure air to sucked out fluid from MC to ABS each line
4. sprayed Brake cleaner into the Caliper with both hose and nipple removed everything shot out clean


My inquiries/suspicion

1. ABS Module issue - but there is no ABS fault unless lock up. I have had ABS issue with my Land Rover but that does not lock anything just tells me ABS not working but regular brake works fine.
2. Is it possible that a pressure valve on the ABS to front left is stuck on one way to Caliper ?
2. Front left Caliper - but Once I release the fluid from the nipple the pressure goes way until start driving


Any suggestion and help will be appreciated. I am in Austin is anyone around has idea.

Thanks

turbineguy

Hi, I had this problem before on my dodge truck (except I didn't have the initial soft pedal problem). It was a collapsed brake line. It would allow brake fluid through under pedal pressure, but there was not enough pressure/suction to get the brake fluid back past the collapse section of brake line and back to the reservoir. Almost like a line lock.


Hope this helps/fixes you problem!

SayeedA

Someone told me the same. I am going to replace those 2 front rubber hose. let's see if the problem goes away.

Thanks

houbmw

I had a similar problem. They told me the brake fluid had water in it and caused my calipers to seize and rust. I had to replace the master cylinder, all 4 calipers and brake lines. My ABS sensors had to also be replaced. Not too sure on anymore details. I hope it works out.

turbineguy

houbmw,


Wow! I'd hate to say it, but I think you got soaked!! Your car would have to have had no brake maintenance ever over 150,000 miles, or the brake fluid reservoir cap left off, to get that bad. Why would you have to replace the ABS sensors because the calipers were seized? I bet that wasn't a cheap bill!

houbmw

$1500...needless to say I took my car elsewhere after and never returned. I suspect that they left the cap off because I had just had the pads and rotors replaced.