Should you use PTFE Tape when installing New Brake Pipes?
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OB, the answer is No. The seal must be between the captive nut on the tube which holds the flare on one side of the join; and the threaded part on the other side of the join. It is the squeezing of the flare between the two threaded parts, not the "watertightness" of the threads, that make the join leak and pressure proof.
Greg
Greg
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Cheers! I do exactly the same, as removing OEM Brake Pipes can be a bit of a nightmare, as they often end up unusable or damaged in some way
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Yup. Tape or sealers only on tapered "pipe" threads. Flared or ferruoe types rely on metal to metal "squeeze".
Caveat, the seats must be "clean" and free of burrs and scratches.
And, use a "flare" wrench, not an open end that messes up the shoulders of the nut.
Some like the ones on my Jaguar's PS must be really tight to avoid seepage.
Carl
Caveat, the seats must be "clean" and free of burrs and scratches.
And, use a "flare" wrench, not an open end that messes up the shoulders of the nut.
Some like the ones on my Jaguar's PS must be really tight to avoid seepage.
Carl
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orangeblossom (01-19-2018)
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#8
As others said, the threads are NOT meant to seal. This is evidenced by not being pipe threaded. The flare at the end, male or female, is compressed against the other fitting, the end is whats doing the sealing and the threads are what is being used to force the two together.
I promise you that a good properly flared fitting will seal on its own, but a shitty flare with tape on the threads will absolutely leak.
Another tip to point out, make sure the ends are in-line with each other when tightening. It is sometimes possible to tighten down hydraulic lines offset, the lines will usually center themselves, but its possible to wedge to pieces together offset, allowing a leak.
EXCEPTION: Some fittings use a washer to seal, the ends typically are square, not male or female flare, because there is no reason to be flared.
I promise you that a good properly flared fitting will seal on its own, but a shitty flare with tape on the threads will absolutely leak.
Another tip to point out, make sure the ends are in-line with each other when tightening. It is sometimes possible to tighten down hydraulic lines offset, the lines will usually center themselves, but its possible to wedge to pieces together offset, allowing a leak.
EXCEPTION: Some fittings use a washer to seal, the ends typically are square, not male or female flare, because there is no reason to be flared.
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#10
JIC and most other flare fittings should NOT be tightened to much it scores the mating surfaces, torque specs are 30in/lb. I used copper JIC washers when calibrating pressure gauges and nip them up, these would hold 10,000psi all day.
We used these mainly because we were changing fittings often and these prevent scoring of the surfaces.
https://www.ebay.com/itm/Seco-7C32-S...-/121099907565
We used these mainly because we were changing fittings often and these prevent scoring of the surfaces.
https://www.ebay.com/itm/Seco-7C32-S...-/121099907565
Last edited by warrjon; 01-19-2018 at 02:22 PM.
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