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Can't stop the weep!

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  • doofus
    replied
    Barry, looks to me like M.C cone is seated slightly crooked by your pics. take a look as it might be my peepers but the pattern on the cone in the M/C is crooked. Luck Doofus

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  • Bellingham Studenut
    replied
    DOT 5 tends to seep easier and sometimes a connection needs to be backed off a hair and re-tighten, or is at a slight angle.
    I've done dozens of cars and always get them to seal without any seal washers.
    Your last picture of a flare looks good now, but may have damaged the master cone.
    Your clamp marks behind might not look good, but the smoothness and angle of front and back of cone are what's important for sealing. Those washers might take care of any master cyl cone damage and imperfections.
    I buy 25'-50' rolls of brake and fuel lines and Eastwood sells an excellent flaring tool for about $200 that works perfect (foolproof for me) every time.

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  • lark55
    replied
    Originally posted by bsrosell View Post
    Lark55, I think you are correct. I got my new flaring die for the Flexcool tool, got new coil of FedHill cunifer (used it all up trying to get this fixed!), made much nicer flares, but still weeping at both MC ports. I finally dried them off really good and got a good look inside the MC ports, and they don't look great. Definitely "max torque" (and 7 attempts or more?) distorted the holes at least, and looks like some scoring on the one. Talked to Jim Turner, ready to buy a new M/C, and he reminded me of the flare washers Brad suggested. (and Gord had good luck with on the Indy car! Congrats!).
    I found a set thru Zoro with only $5 shipping, so ~$10 total for 10-pack. On their way. Will let you know. Otherwise, new M/C time.
    Thanks Jim and Brad!
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    I certainly hope the new master cylinder works for you. The tube flares look better. We would typically assemble all of our AN test systems with nose seals (or flare washers if you prefer). The nose seals would protect both the tubing flare as well as the fitting flare as well as seal the connection. At times, if there was a ding or scratch on either sealing surface it would transfer to the tube or fitting flare.

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  • Topper2011
    replied
    The flare looks A LOT better!

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  • bsrosell
    replied
    Lark55, I think you are correct. I got my new flaring die for the Flexcool tool, got new coil of FedHill cunifer (used it all up trying to get this fixed!), made much nicer flares, but still weeping at both MC ports. I finally dried them off really good and got a good look inside the MC ports, and they don't look great. Definitely "max torque" (and 7 attempts or more?) distorted the holes at least, and looks like some scoring on the one. Talked to Jim Turner, ready to buy a new M/C, and he reminded me of the flare washers Brad suggested. (and Gord had good luck with on the Indy car! Congrats!).
    I found a set thru Zoro with only $5 shipping, so ~$10 total for 10-pack. On their way. Will let you know. Otherwise, new M/C time.
    Thanks Jim and Brad!
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  • lark55
    replied
    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.

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  • bsrosell
    replied
    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.
    BUT:
    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.
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    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!
    Barry
    Attached Files
    Last edited by bsrosell; 05-03-2021, 02:09 PM.

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  • Topper2011
    replied
    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.


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    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.

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  • garyash
    replied
    I called Tim at FedHill, the main supplier of the Cunifer tubing. He was surprised that we couldn't get the lines sealed. He suggested a couple of things.

    1. Look into the fitting to be sure the cone isn't damaged or scored.
    2. With the nut slid back, push the tube into the fitting and see how deep it goes and how much thread is exposed. Also look to see if the diameter of the flare is big enough to engage a good portion of the cone.
    3. If short nuts are being used, try screwing a bare short nut into the fitting to be sure it doesn't run out of thread before pressing the back of the flare. Long nuts may be required in some fittings.
    4. He wasn't too concerned about the possibility of over-forming the flare as the tubing is soft enough to deform if the nut is pressing correctly.
    5. Check the flare and cone in the fitting to see if there are marks from contact. Some marking is expected from the nut and the cone contacting the tube. But, there shouldn't be scratches or grooves that run from center to outside, just round and round marks.
    5. He did ask me where I bought the nuts. While I got some from FedHill, I got some others from the local chain parts store. Could be I bought less-than-perfect quality nuts.
    6. He thought that the copper gaskets shouldn't be needed, especially on 3/16" tube.

    I'll be checking these issues on my car. With as many leaks as I have, I must be doing something wrong.

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  • 345 DeSoto
    replied
    bezhawk - Nitrile being the Operative word...not "rubber".

    Nitrile rubber, also known as nitrile butadiene rubber, NBR, Buna-N, and acrylonitrile butadiene rubber, is a synthetic rubber derived from acrylonitrile (ACN) and butadiene.[1] Trade names include Perbunan, Nipol, Krynac and Europrene. This rubber is unusual in being resistant to oil, fuel, and other chemicals.

    NBR is used in the automotive and aeronautical industry to make fuel and oil handling hoses, seals, grommets, and self-sealing fuel tanks.[2] It is used in the nuclear industry to make protective gloves. NBR's stability at high temperatures from −40 to 108 °C (−40 to 226 °F) makes it an ideal material for aeronautical applications. Nitrile butadiene is also used to produce moulded goods, footwear, adhesives, sealants, sponges, expanded foams, and floor mats.

    The "O" rings ARE compressed between the fitting and the flare, but not so they are crushed and destroyed.... and they DO hold the brake pressure without leaking. I have been using them in all my fluid systems, for decades, and have never had any sort of failure....
    Last edited by 345 DeSoto; 04-29-2021, 12:04 PM.

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  • bsrosell
    replied
    Thanks guys. (ha! yes, I've been reaching for my 3/8" flare wrench so often started saying 3/8"lines vs 3/16" :-)
    I'm thinking Doofus is right; very subjective "how much too much" pressure, with my hydraulic pump flaring tool. Would make sense to back off and let it spread and seat itself. Will try that first.
    Re: the comments about 'tighten it some more", that was the answer for most of the OTHER fittings in the system, finally stopped weeping, but these I literally rounded nuts off and/or could not get ANY more torque on them. Maybe a slightly different flare on the M/C and the pressure valves in the Turner kit, since those have been the most problem to seal, and have done flaring the same (and multiple times) for both of those. Will let you all know how backing off on the 2nd flare works. Wish I'd known about those seals before I started the whole job 2 years ago, would have saved a LOT of frustration building the whole system from scratch and DOT5! :-) (hope my fuel lines fair better; have yet to put gas in the tank to try and fire it up yet!)

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  • bezhawk
    replied
    An "O" ring of rubber is asking for trouble. They can not possibly hold the pressures generated by braking systems. You are talking at least 1200 lbs/sq inch. If they didn't leak it's because you tightened them past the rubber, and the metal is actually doing the sealing.
    I only posted US Tools as an example. I have purchased the copper flare gaskets from Graingers as well as made them up from some sterling silver I had left over from my jewelry days.

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  • 345 DeSoto
    replied
    I haven't had a single problem with leaks, seeps, or weeps since I started installing the appropriate size nitrile "O" ring into the fittings before tightening down the flared end into it...period. Fuel lines, brake lines, transmission cooler lines, etc, etc...

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  • bensherb
    replied
    The only time I've had any flare I've made weep regardless of tube material was if I over tightend the flaring tool in the final step, (which it looks like you may have done) and crushed the flare or when I didn't tighten the fittings enough when using DOT5. I've used copper/nickel tubing many times and have never had an issue with it. Inverted flare fitting shouldn't require more than about 12 ft lbs torque, and banjo bolts around 22 ft lbs even with DOT 5 fluid. By the way, yes, Volvo has been using it since the '70s.

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  • garyash
    replied
    The Parker copper gaskets look like a good solution. However, USA Tool has a $50 minimum order, tough to reach with $0.80 parts. MSC Industrial Supply has the gaskets for $0.84 each but wants $12.95 for shipping. I bought 20. Some parts on Amazon, as well.

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