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Can't stop the weep!

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  • #16
    Originally posted by bsrosell View Post
    Hi, thought my brake line woes were past 2 years ago, finally got all my new Cunifer lines and DOT5 sealed up. Recently, since still just a chassis, removed MC to return to Jim Turner for adding the port to enable a reservoir for refill mounted on firewall. Ever since, can't get the lines to stop very tiny weep (overnight to show). Removed line and remade both ends, as well as I know how (and the rest of the system has been dry, most the 'first time'). Don't know what else to to do. Tightened as tight as possible (over three nights of trying to stop the weep). MC ports LOOK ok but really hard to see in there if somehow scored, don't know how, Always very careful no burrs, blew out components w/ brake cleaner before assembly, etc.. . If it WERE the MC ports now, is there anyway to replace (or have NAPA or ?) replace just those MC fittings? Or cost more than buying a whole new modified cylinder (again) from Jim?
    attached photos of my flare. one problem I noticed with this 3/8' Cunifer, is a bit thick, so I've had to gently file away the pinched area that swells; get it to where the nut freely turns and seats. And, worked on all my OTHER many fittings even before I started fine-tuning them a bit like that.

    I did DOT 5 so no cylinders would rust out (already had the Cunifer, overkill in that case I know). If I had it to do over again, would have stuck with DOT3 I think. But hate the thought of rebuilding ALL of the brand new wheel and M/C again to clean the DOT 5 out :-(.
    Anything look amiss with my flares? Or other tips? I'd never done flaring before, but have a good hydraulic set, practiced a LOT, and did the fuel lines after the brakes, so feel I'm "doing them right" at this point.

    Finally completely out of my 3/8" line, could maybe get one more flare out of existing. BUT, have made multiple and always end up with a slight weep one end or the other. Only this set of two lines, from pressure valves to cylinder!!! all others sealed. So frustrating!

    Thanks. Click image for larger version Name:	brake line flare.jpg Views:	0 Size:	19.5 KB ID:	1892063 Click image for larger version Name:	brake line fare side2.jpg Views:	0 Size:	8.0 KB ID:	1892065 Click image for larger version Name:	brake line fare side.jpg Views:	0 Size:	59.8 KB ID:	1892066 Click image for larger version Name:	brake fluid weep.jpg Views:	0 Size:	103.9 KB ID:	1892067 Click image for larger version Name:	MC.jpg Views:	0 Size:	89.6 KB ID:	1892068
    I may be mistaken, but does your flare have a bit too much material in the "port" area? It appears that your flaring tool is gripping too low on the tube. Here is a factory made flare.

    Click image for larger version  Name:	P4290855.JPG Views:	0 Size:	69.0 KB ID:	1892374

    I would imagine that the center of your flare is bottoming out on the male end of the fitting before the outer edges seat, giving a poor seal? Think of trying to fit a small diameter washer on a cone, it would sit high on the cone, using a larger diameter washer, allows it to sit lower on the cone. Maybe your small hole is limiting full contact with the male flare fitting. It's probably why you are rounding out the nuts, in effect trying to stretch the hole. I hope that makes sense. Other than that I am perplexed.
    Last edited by Topper2011; 04-29-2021, 04:58 PM.


    • #17
      Update: midweek I re-did my two lines to MC, per Doofus suggestion of "lay off the cone" a bit. At first i thought it did it, not weeping immediately! :-) Next day, still a dab (and I spray with brake cleaner in threads, NOT residual fluid). So, started experimenting and searching web on Flextool use and flaring in general (sites that show I last visited in 2019; dejavu). Confirmed tubing should be JUST LEVEL with the die (which I carefully do), and basically that i was doing everything correctly with the Mastercool tool.
      A problem I've always had with the 3/16" lines, and attributed to the Cunifer, is I always end up with a bit of a 'flange" on the back. No-one had THIS problem on YouTube.... And my 5/16" and 3/8" (for fuel lines) were perfect every time.
      Originally I got to where I was making nice flares except for this, and simply filed off the "excess". But, often got distorted flares too. I measured the Cunifer last night, and it is exactly 3/16".

      Has anyone had this problem?
      The die does not close all the way, (doesn't for other sizes either) but experimenting with REALLY cranking it down until die had NO gaps didn't help (worse if anything; YouTube vids also indicate "no need to tighten past snug")

      Below are photos showing the step-by-step "normal" process I used for the entire brake system (except I'd carefully file those outcroppings off).
      I've noticed my tubing cutter (for 3/16"; good one is not quite small enough) doesn't cut quite flat so will go buy a new one and try that.
      But doesn't seem THAT would have anything to do with that ridge under the flare..... For the life of me can't figure out what I'm doing wrong; or if I just have a bad MasterCool die.
      Click image for larger version  Name:	1.jpg Views:	0 Size:	60.7 KB ID:	1892800 Click image for larger version  Name:	3.jpg Views:	0 Size:	42.1 KB ID:	1892801 Click image for larger version  Name:	5.jpg Views:	0 Size:	59.1 KB ID:	1892802 Click image for larger version  Name:	2.jpg Views:	0 Size:	47.0 KB ID:	1892803 Click image for larger version  Name:	4.jpg Views:	0 Size:	57.2 KB ID:	1892804

      2nd question; assume I finally fix this at MC, and I have no weeping anywhere else in brake system. With all the "pumping" of pedal I've done for bleeding brakes originally 2 years ago, and now again repeatedly testing for leaks w/ the re-installed MC, is it "if it ain't broke, don't fix it", or are "all connections suspect and might START leaking someday when really USING the brake? Thinking of more pressure when really 'standing on the pedal" in a hard stop....

      Thanks for any feedback!
      Attached Files
      Last edited by bsrosell; 05-03-2021, 02:09 PM.


      • #18
        If these were AN type fittings I could probably offer better help but I will try to pass on what I have learned during my working career. If you are getting a good seal at the other flares it would indicate they are being properly made. I think the problem is with the master cylinder fittings flare. Would it be possible to use another known good master cylinder or change out those fittings? I have found that the tendency to over torque a connection to stop a leak is usually not the best solution. The nose of the fitting or the flare itself will distort and still not stop a leak. There should be a torque spec. range for these fittings. We would typically lube the back of the flare where the fitting nut rides to ensure that the line flare did not try to turn with fitting when tightening. I hope this helps. I used to spend a lot of time leak-checking test systems and know how frustrating it can get.