Thread tape on brake lines?

[Tcoat]

Originally Posted by justatroll

Sorry, I cant help myself.
You are telling him the right thing (dont use thread sealant on brake fittings)
But for the wrong reason (teflon tape cant seal threads).

In fact teflon tape does seal threads, it is used on almost all threaded pneumatic fittings because of the sealing characteristics.

The real reason one does not need thread sealant on brake fittings is that by the time the working fluid were to get to the threads it has already leaked past the seal.
The seal is the metal brake line smashing up against the fitting mating surface.
The threads ONLY purpose is to apply massive force to press the two mating surfaces together.

AN and flare fittings are also this class of fittings.

In fact, on rigid brake lines, if the fluid leaks past the primary seal (the crushed tip of the tube), it wont even try to leak out the threads, it will come up the middle of the fitting along the tube and out the top of the fitting.

Had this very debate with my son (the most technically challenged individual in the universe from his mothers side) just yesterday. He insisted on putting Teflon tape on the hose connections of his new washing machine. No amount of explanation that the treads just provide the force for the fitting to seal against the washer was acceptable to him. He taped the crap out of the threads and went and turned on the water as I stepped back about 3 paces. He got soaked as the Spray came out around the base of the fitting since the tape completely prevented the fitting from seating against the washer. He now understands the concept of fitting that are pressure sealed.

[Seth Hawkins]

Originally Posted by Ultramaroon

Nobody asked why you're considering this. Why are you considering this?

This is my first time doing anything with hydraulics, or brakes, and this type of fitting.

Basically, out of pure ignorance of how hydraulics work. But instinct told me to use it to seal the fitting.

[Ultramaroon]

Originally Posted by Seth Hawkins

This is my first time doing anything with hydraulics, or brakes, and this type of fitting.

Basically, out of pure ignorance of how hydraulics work. But instinct told me to use it to seal the fitting.

Sure. It's what I figured but wanted to verify before I changed directions on you.

More important than considering teflon tape is to acquire a flare nut wrench. Open ended wrenches are a ticket to misery and failure. If you google the term it will become immediately clear. Never mind teflon tape. Not applicable in this case. Good luck!

[Northwest86]

Originally Posted by justatroll

In fact teflon tape does seal threads, it is used on almost all threaded pneumatic fittings because of the sealing characteristics.

You'll find that those threads on the Pneumatic system are tapered most likely. It's sealing capabilities are so low that it's more luck if it seals something. It can aid in some small way but it's primary job is to lubricate and if something should need sealing, the correct material should be used. If you use it on a hydraulic system and a parallel thread I can guarantee that joint will leak/seep oil. And then that person would get slapped silly for putting thread tape on a hydraulic system because of how easily it can mess something up and stop production on an entire mine/smelting site. Hell anything can be a sealant. I've had to make custom Gland type seals out of a shoelace before to get something running while we were waiting on parts. Show laces are good for 10000Psi in the right applications.

If it's tapered, you lubricate. If its Parallel you use a gasket. Be that an O-ring or liquid gasket such as 567, Mastergasket etc. If its a tapered metal contact such as brake lines, JIC/AN fittings etc then you fit dry or if appropriate with a dab of oil to help prevent Galling.

[Northwest86]

And as mentioned Flare nut spanners are a must. Otherwise I'd be willing to bet money you'll have to resort to Vice Grips once the nut is rounded off. Thats one thing I definately agree on.