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School me on replacing hard brake lines

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    School me on replacing hard brake lines

    Hey E30 gurus, can you please tell me what I need to know when replacing my hard brake lines? I'm doing a rear subframe refresh, and some of those lines are pretty corroded.
    1. Who sells the lengths of brake pipe needed?
    2. What material should the lines be made of? Does it matter?
    3. What tools are required to do the job?
    4. What size threaded tips should I use?
    5. What brand is the best quality or most like OEM?
    6. Is it a good idea to just order the lines pre-cut and prepped for install based on the realoem part numbers?

    All my soft lines are new steel braided ones labeled with 'DOT', and I have that T-fitting on order.

    THANKS FOR THE HELP!
    Attached Files
    R135 /// 1990 Alpinweiß II 325is
    └┼┼┘ /// 1993 Black/Black Convertible (sold)
    ..24

    #2
    If you order factory lines, they will be the correct length, but will need to be bent.

    A bender like this will get the job done:

    https://www.amazon.com/Ion-Tool-3-in...2326722&sr=8-3

    Comment


      #3
      Get copper nickel lines, SUR&R among others sell kits with fitting, albeit at slightly higher than standalone bits.

      Comment


        #4
        I use copper nickel 3/16 brake line (parts store or online should have rolls for sale) and make my lines by hand. The length measurements are available on RealOEM, in the brake pipe section. You can also use your old lines as a template for bends once they're removed. For the fittings you'll be looking for an M10x1 bubble flare nut for 3/16 line, which are sold in packs at autoparts stores or you can get them online. The most critical thing if you're making your own lines from scratch is that you get the flares right. Our cars require metric ISO bubble flares... So you'll need a flare tool decently capable of making this type of flare. Sent from my moto g(6) using Tapatalk
        (OO=[][]=OO) For Life

        Comment


          #5
          Originally posted by 15Michaeljoseph View Post
          I use copper nickel 3/16 brake line (parts store or online should have rolls for sale) and make my lines by hand. The length measurements are available on RealOEM, in the brake pipe section. You can also use your old lines as a template for bends once they're removed. For the fittings you'll be looking for an M10x1 bubble flare nut for 3/16 line, which are sold in packs at autoparts stores or you can get them online. The most critical thing if you're making your own lines from scratch is that you get the flares right. Our cars require metric ISO bubble flares... So you'll need a flare tool decently capable of making this type of flare. Sent from my moto g(6) using Tapatalk
          Thanks! This is great info!
          R135 /// 1990 Alpinweiß II 325is
          └┼┼┘ /// 1993 Black/Black Convertible (sold)
          ..24

          Comment


            #6
            I found the correct rear trailing arm pipes in bendable cunifer at my local NAPA. Had to order them - a couple of days. Verify size and flare type. Laid them next to the original pipes and slowly worked them by hand with a can and a big socket until they matched.

            Comment


              #7
              I also found this guy has some great advice:

              https://ricksfreeautorepairadvice.co...e-line-splice/

              Keep in mind that if you are going to cut your own pipes and press flared ends, buy the most expensive flaring tool you can afford. Bubble flares are hard to make well with a $15 tool.
              R135 /// 1990 Alpinweiß II 325is
              └┼┼┘ /// 1993 Black/Black Convertible (sold)
              ..24

              Comment


                #8
                Originally posted by Aleman View Post
                I also found this guy has some great advice: https://ricksfreeautorepairadvice.co...e-line-splice/ Keep in mind that if you are going to cut your own pipes and press flared ends, buy the most expensive flaring tool you can afford. Bubble flares are hard to make well with a $15 tool.
                If you have the money, the Mastercool hydraulic flare tool is the one to get imo. I borrowed a friend's to make my hard lines after my cheap tool broke, and it just makes an absolutely perfect flare every time. 100% will be buying my own the next time I have to do any work with brake hard lines. Sent from my moto g(6) using Tapatalk
                (OO=[][]=OO) For Life

                Comment


                  #9
                  This but the mastercool kit is retarded money. Like $400+. Amazing tool and I own it, but Im a professional. I made hundreds and hundreds of bubble flares with a $40 kit before i got it. Dont waste good money on an expensive tool. waste a few dollars on extra NiCopp line and an hour of practice. NiCopp line flares like butter compared to steel.
                  "In God we trust. All others must bring data." -W. E. Deming

                  /// 1987 325is /// Project Thread
                  Past: 87 is, 88ix, 88 i, 87 ic, 89 ix, 17 others.

                  Comment


                    #10
                    Originally posted by Conrad311 View Post
                    This but the mastercool kit is retarded money. Like $400+. Amazing tool and I own it, but Im a professional. I made hundreds and hundreds of bubble flares with a $40 kit before i got it. Dont waste good money on an expensive tool. waste a few dollars on extra NiCopp line and an hour of practice. NiCopp line flares like butter compared to steel.
                    That's true - the copper lines are pretty soft and easy to flare. But, DAMN, the BMW OEM lines in the car are steel, and I struggled to make the flares even with a $240 tool from SUR&R. It's hydraulic, so it's easy on your hands. It makes perfect flares on the copper lines. The issue is that the steel piping just slides out of the grip unless you put some ape-like tightening torque on the tool's bolt that holds the pipe in place.

                    For my project to replace rusty brake lines, I had to cut off the pipe on the left side of the T-fitting in my pic above. That pipe goes all the way to the engine compartment, and I didn't want to redo the whole length. My bending skills suck, so I cut off the rusty end and connected the new copper to the OEM steel with a union fitting. The bitch part was making the bubble flare on the steel end. Cost me weeks of trying/breaking different tools to finally get it done.
                    R135 /// 1990 Alpinweiß II 325is
                    └┼┼┘ /// 1993 Black/Black Convertible (sold)
                    ..24

                    Comment


                      #11
                      Using a Cal Van tool to make bubble flares on stainless steel hard lines. The ones on the bottom are my failed attempts so far. The one on top is an OE BMW hardline brake line, that’s what they’re supposed to look like. I’m going to try a few more times.
                      Attached Files
                      1990 325is Brilliantrot/Natur

                      Comment


                        #12
                        Unless you are a pro, I would strongly advise against SS if you are tryin to flare yourself. Just had all my rear lines done in SS and would very likely go with Cunifer/Nicopp if I was doing it again. Cost is similar and so is the performance.

                        Out of three shops in my area, only one did a decent job with the SS bubbles. They didn't come out perfect but good enough. One of the shops gave it a try but couldn't do it so I wasted some time just going back and forth. If a hydraulic shop is having issues then its not a good sign. Also, it was a real PITA to do final adjustments when installing the lines in the car. SS tube is a really tough material to work with without proper tools. Lastly, if you are using SS lines, get SS fittings as well, obviously.
                        Last edited by fitswell; 02-16-2021, 11:03 AM.
                        ------------------------------------
                        01.5 S4 Avant - Sold
                        88 325iS - In pieces
                        91 e34 - Totaled by some dumbass
                        90 325i - Daily
                        06 e91 - Sold

                        feedback thread

                        Comment


                          #13
                          • Who sells the lengths of brake pipe needed?
                            Realoem has the catalog with lengths, You may find a local hardware store who has something close, Depends on how nice you want the end result. 1/8 extra sometimes is hard to hid and keep things tidy.
                          • What material should the lines be made of? Does it matter? Personal preference.
                            I've done this job with Genuine tubing, Aftermarket Tubing, Nicop, Cunifer, and stainless steel. I would recommend the 3/16 Cunifer for the ease of bending and less aggressive on bending and flaring tools with their M10x1.0 tube nuts http://www.fedhillusa.com/
                          • What tools are required to do the job?
                            This is a china knock off of the fedhill tool or re branded. The cheaper ones will work, But this one works nicely and wont kink up the lines. https://www.eastwood.com/professiona...oaAvQmEALw_wcB
                          • What size threaded tips should I use?
                            M10X1.0, Some masters have a M12x1.0. I go with the longer tube nuts on the Cunifer / Nicop because soft it is and how much it squishes.
                          • What brand is the best quality or most like OEM?
                            Genuine - Ends already done, Just have to bend and go, Tube nuts perfect depth. Will have to replace in another 15/100 years depending on environment and how often brake fluid is changed.
                          • Is it a good idea to just order the lines pre-cut and prepped for install based on the realoem part numbers?
                            Time VS Tools VS Budget
                          Other bits you may want
                          34 33 1 152 494 - Brake pressure regulator
                          34 34 1 163 565 - Clip
                          34 34 1 111 435 - Distribution piece
                          34 30 1 161 567 - Clip
                          34 34 1 163 565 - Clip


                          I do see the P/N right off hand for the M4 screw bracket that hold the lines to the chassis, They usually like to strip, Seize, or brake off..
                          Last edited by moatilliatta; 02-16-2021, 11:56 AM.

                          I was up above it, Now I'm down in it ~ Entropy - A Build thread.
                          @Zakspeed_US

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