Rear Brake Lines Rusted Out - Anyone replace the hard lines with Stainless Steel?

[RonVF]

Originally Posted by Calipsoe

I just had to do this on my 2005 X5 and I replaced the rear lines with AGS NiCopp. Supposedly this copper alloy has been used for brake lines by other manufacturers for decades. (Audi, Porsche, etc.)

I used 2 - 25 foot rolls of NiCopp and ran each line as a continuous run. This should cost around $60 online (~$30 per roll). NiCopp Nickel/Copper Brake Line Tubing Coil, 3/16" x 25' - AGS Company AGS Company You'll have some tubing left over from each roll but a single 25 foot roll is not enough to do both lines.

I ended up using an HFT50 flaring tool after buying a cheap one and being disappointed with the quality of the flares. The HFT50 is not cheap ($140) but it is a quality tool. http://surrauto.com/documents/HFT50H...laringTool.pdf Practice! Practice! Practice! before making the flares on the car. Also note that the flare type you want is a DIN Mushroom flare. A bubble flare may work but it's not the correct flare type.

Most of the bending I did by hand but in the wheel wells where the connection is made to the rubber brake line I used this bending tool from Harbor Freight for $10. 1/8" to 1/4" Tube Bender
It gave nice consistent bends and is a good size for fitting in tight areas if needed. I also used it for making the bends going into the distribution box.

Once I got the NiCopp lines in place I bought 4 feet of 3/16 ID rubber hose and cut it in 2" or 4" sections and slit it along the length and used it as additional vibration protection bushings for spots where the lines may cross or they may come in contact with the body. These were tie wrapped in place.

FYI BMW sells the steel lines cut to length BUT that will cost you about $200 for all the lines. But the big problem is going to be joining the lines that run under the trunk over to the right rear. Getting a wrench in there will be too tight unless you connect them before installation. Using a continuous line avoided that headache as I just fed the line from the left side over to the right side.

Also be aware that BMW recommends using Low Viscosity DOT 4 brake fluid. I chose to use BMW fluid from ECS Tuning in 12oz bottles. It's cheaper to buy the 12oz bottles than a gallon and if you dont use them all they will stay sealed and be good for your next brake flush.

WARNING! My lines rusted out in the usual spot right behind the drivers side wheel well under the plastic cover. However I noticed significant corrosion on both lines hidden behind the left front wheel well splash guard and on the right rear line as it travels from left to right under the trunk and over the differential. Just checking under the long plastic cover is not enough!

Wow! Great write up! I have been searching the web for information just like this. Had the left rear line on my wife's 2006 X5 (198k)blow under the drivers door, last weekend. Cars in the garage up on jacks, panels are off and I purchased all new lines from the ABS back to the calipers from BMW for $400. Once I saw the lines were not pre bent I got a little concerned. Called the 2 local dealers here in Albany NY and one quoted me 12 hours labor at $135 per hour and the other quoted 9 hours at $127 an hour.. So now I'm in the middle of trying to do the repair myself.
I tried bending the new oem steel line off the ABS myself but that thing has so many complex bends I screwed it all up. As a precaution I did purchase 2 25foot rolls of the NiCopp along with fittings and a bubble flaring tool from Napa. Now reading your post Calipsoe, I see that the ends are mushroom and not bubble.. Not sure how that will work or where to purchase the one you referenced. Here is my question or questions. If I run the continuous 25 ft, did you start at the back and work forward or in the front and work back? Also you mentioned how you bent at the rear, near the rubber lines but how about all the other bends including the wheel well before the ABS? Did you ge the new line placed into all the line clips including the one that crosses over to the right rear?
Your Warning is exactly what I found to be true. I didn't want to repair just the broken line only to have it fail somewhere else. This is my wife's vehicle and she isn't very good at hearing or seeing the warnings, like low brake fluid.. Fortunately I was driving it last week when the line ruptured.
Thank you for telling us about those little plastic retainers also, I'm sure I would have been trying to figure out how to get the old ones back in..
Much appreciated!