Technical sealing pipe thread on brake fittings

I have made a lot of brake lines in the past but have never had to deal with pipe thread fittings (through the frame fittings and proportioning valves). What do you guys use to seal those pipe thread joints?

Thanks!

 

I thought gasoline used a different set of threads..

 

No gasoline in brake lines.I never had to use anything to seal the fittings.

 

I use ptfe tape. Has worked with no issues for 30 years or so with no issues. Take care to keep the tape away from the internals to avoid any brake problems. Surplus tape on the outside can easily be removed so the joint looks neat. I do agree though that pipe thread in a braking system somehow doesn't seem right, but it is commonplace in aftermarket braking equipment.

Chris

 

Don't know what you're talking about, but comnfirming what to use on these pipe threads comes from having put together a lot of gas lines in the past -I never use Teflon tape on gas lines because if they get inside, they will clog a lot of things up. Are there similar concerns with brake line pipe thread fittings? Are there certain sealants to avoid (that break fluid will dissolve).

 

Pipe fittings on brake parts? Proper "thru the frame fittings" and proportioning valves should have flares internally and should not need sealing tape.

 

What is it with some peoples aversion to NPT fittings in a brake system? Every race car and hot rod I have built for the last 40 years has had some NPT fitting somewhere in the system. Can some one tell me exactly why it is not a good idea?

 

Pipe thread can use a lube, like never sieze, but no sealer is needed as the threads are tapered and will lock mechanically.

 

I don’t have any on mine.
Just good ole friction.
But it doesn’t take a lot for 5 or 6 psi.

 

Use the Teflon tape. Hard to get some of the poorly made pipe fittings to seal without it. Just for the naysayers, black pipe is used in hydraulics in all kinds of equipment and never fails.

 

no sealer...but if you have fitting that wants to seep a little, then add a little pipe thread sealer and try again. Sometimes there are enough defects in the thread that it will not seal perfectly

 

Maybe ....

 

I have had some problems in the last year or so, especially in NPT br*** fittings with leaks. Makes no difference if its the hardware store or Advance/Dorman. If they are produced in China and the threads aren't quite to spec or what. I've started using a drop of Pematex sealer on all NPT. I will not use tape! As far as thru frame fittings if you are talking Speedways they will leak like the USS Valdez. I thru mine away and ordered Russel's and problem solved.

 

Pipe threads need some sort of sealer. In a plumbing application, Teflon tape or pipe dope is required as the threads are metal to metal contact. Teflon tape is not recommended on any hydraulic system including a brake system. One small piece of Teflon that comes loose can cause havoc in a hydraulic system. What I use on pipe threads on automobiles is a product from Loc***e called 569 Thread Sealant or Loc***e 545 Pneumatic/Hydraulic Seal. Of course no sealant is used on flare fittings.

 

Lately the NPT brake fittings have been coming in the package with red dope on the threads.

 

More like a lock***e sealant, very hard to remove. A little sealant goes a long way, just a dab on the threads and smear around them. as far as the "tape" goes, people tend to use the too wide version (hardware store) and get sloppy with it. search out and get the 1/4" wide stuff. 1 1/2 wrap in the right rotation, set in the threads and install

 

Don’t use Teflon tape unless you can be certain it won’t slip on install and make it’s way into the system.

like has been said , lately I’ve been getting some ****py fittings and pressure sensors that simply won’t seal .

a dap of pipe dope or the lock***e anaerobic “ red jelly” works great.

just a drop , your not icing a cake !!

 

Pipe threads…Permatex #2. Any flare fitting….nothing. AN aluminum to aluminum…a slight dab of neversieze at the beginning of the threads.

 

The pipe seldom fails but tapered threads leak. That is why the industry got away from using them years ago. Straight thread, tapered (JIC) or 4-bolt flange fittings are best by far. You will see pipe threads on the low pressure side of some systems but the high pressure side should have socket weld fittings that adapt to straight thread or flanges where the sealing is done with o'rings, not tapered threads. And thread tape ****s. It works when installed but if you remove and replace the fitting you risk a chance of the tape falling into the system, as stated above. The system will breakdown liquid sealants but not tape. It ends up in areas that can cause a lot of grief. One other thing; the pipe used for those systems is not off the shelf at the plumbing store. It is pickled, oiled and plugged (POP) to clean it and keep it clean during storage. The high pressure side is usually SCD80, low pressure is SCD 40.
I would be fearful of using tape in an automotive brake system.

 

Well if you have ever installed a Ford inline brake light switch in your hot rod you have used an NPT fitting. Plus two adapter fittings to hook to flared fittings on the lines in and out of the T most of the time.
It isn't cheap but Loc***e 545 will get the job done in a very thin bead around the thread.

Tape = follow what dreracecar said in post 16. Leave the bottom thread or two bare when you put the tape on and don't put so many wraps of tape on that the female threads push it all back off.

 

Plenty of thru frame brake line fittings and others use npt. I use a permatex thread sealant.

 

I recently built a side lift arm for my log splitter for those big chunks. I added a valve and cylinder into the splitter system. All hydraulic cylinders and valves as far as I know use NPT threads. I used big box store NPT stuff. I used pipe dope (Permatex) on all NPT fittings. Started it up and had leaks everywhere. Took it all back apart, a real PITA, and used tape this time. Less leaks but not "no leaks." Partially dis***embled again and wrapped the fittings still leaking with MULTIPLE wraps. I even had to change out one persistent leaker, but finally got all the leaks stopped. At least half a day. I attribute all this mess to poorly made fittings. I know in a perfect world that NPT fitting are not supposed to leak without sealer, but I have never managed to achieve that plane of existence.

 

I use a very small amount pipe joint compound not so much to seal as to
lubricate the fittings. If the compound squirts out of the tightened fittings you have used too much.Tapered pipe threads should seal without Teflon tape or compound. Using compound is like chicken soup when your sick. Might not do anything but can’t hurt.

 

I started using Loc***e 545 and haven't had anymore sealing problems.
I recently used it to do a complete brake project and it worked out so well that I'll continue to use it.
I'll save the pipe dope for pipe fittings and use the 545 for brake fittings from now on.

 

NPTF dryseal threads are // supposed // to seal without tape, pipe dope etc.
They (NPTF) differ from NPT in the major and minor diameters or something
Then kind of By definition regular old NPT are expected to need something to really seal.

 

I will admit that the use of NPT fittings in brake systems makes me a little nervous since I've seen many pipe fittings crack or break at the threads due to the lack of material thickness at the bottom of the threads (minor diam.). Also, the source of and quality control of today's parts is always suspect. But they are a fact of life when using pressure brake light switches or residual check valves, etc. I have an old roll of thin, 1/4" wide Teflon tape that I use, applying it back from the end a thread or so and one and a half turns. It's been a long time since I was able to ***emble new fittings bare without a leak.

 

There is a Teflon tape made by lock***e that looks like dental floss.
I bought a roll once and have never seen it again ( in my van or at a store )

it fits in the grooves of the threads and is made for critical sealing of threads .

If you can find it try it.

I bet when the day comes and I need to empty out my work an I’ll find 23567898654322 rolls of Teflon and electrical tape !!! Can never seem to get more then 1 use out of the roll when I’m on the road and “ **** !” It’s gone into the abyss

 

The F stands for fuel. The roots and crests on the thread contact each other which eliminates the spiral path of the standard NPT threads. Hardware store fittings are most likely standard threads. Sometimes no leaks, sometimes leaks.

 

It's a hit or miss with pipe dope, seems to work with plumbing (low pressure) anything else it's too chunky. I use these and haven't has a problem with hydraulic, brakes or even high water pressure (3500 psi).

 

gotta love it....