Brass ferrule or Push to lock for air lines

[Darkspeed]

Any advantages using brass ferrules and nuts instead of nylon Push to lock fittings for the pneumatic systems?

[Melbo]

I have used both with success.  Just a matter of preference.  You will hear varying opinions.

Always fun to hear what will work and what won't

HTH

Melbo

[luvrbus]

All I use now is the push in just for convenience for me they do leak over time though,they are touchy the line end has to be perfectly square when installing or they leak   

[Iceni John]

I still wonder if even the DOT push-in fittings with their reinforcing tube are as secure in a high-vibration environment as traditional compression fittings.   Maybe for exposed air lines to brake chambers and valves I would still use good ol' compression fittings, but for everywhere and everything else I'm more than happy with push-in fittings, whether for air or for water.   I use the Alkon AQ DOT push-in fittings.   I also make sure the tube cannot move at all relative to the fitting, securing it within a few inches and then every two feet.

Not only cutting the ends absolutely perpendicular is critical, but making sure there are no external burrs to catch on the O-ring is also vital.   I always pull the tube so the release shoulder slightly extends out the body, then it seals 100%  -  if the release shoulder is pushed in flush with the body it can sometimes slightly leak.

John

[kyle4501]

We use push in fittings at work only because of the time savings. Leaking air isn't an issue since our screw compressor can keep up.

However, if you look at the design of the push in fitting, it uses an o-ring to seal the connection. However, that o-ring is in tension, and o-rings seal better when compressed. When the o-ring breaks, the leak may be enthusiastic 

This is why I prefer to use the DOT brass ferrule fittings - especially if it is in a location that I really don't want to visit ever again. 

But, there will always be places where a push in fitting seems to be the chosen compromise . . .   

[Jim Eh.]

I hate push connect fittings. The problem is that after as little as two temp cycles (summer/winter) they can start to leak. Just as the plastic air line that comes off a reel has a coil memory, so too does that o ring cause some memory indentation in the plastic air line. Did I mention I hate PTC fittings?
Not only do they leak after time, once in the elements for any extended length of time the damn lock collar seizes up and you have to pitch the whole fitting anyway. Now, if you have luck as good as mine, the air line is about 1/4" too short. Add a union and a new end fitting, plus a small amount of air line. BTW, did you know I really hate these PTC fittings?
But you could always use them...again, and again, and again. A little more effort using the compression style fittings but once it is in place, it's done. Just my ol' school way of life.

[Darkspeed]

Ok glad to hear it, I always have used parker brass but I did not know if there was any advantage to the push to locks.

[Jon]

We have feedback from a lot of conversion owners and the issue of push in fittings compared to compression fittings is crystal clear.

First we are talking solely about DOT fittings, not something you can pick up at a big box store.

Push in fittings have become the greatest source of leaks as they age. Apparently the O ring or the sealing ring ages and over time small leaks appear. One fitting leaking a bubble or two a minute is no big deal, but when a coach has hundreds of push in fittings the problems associated with stopping leaks is substantial. When the aged push in fittings start leaking owners are going to the expense of replacing all of them with compression fittings which last forever.

[luvrbus]

It's a catch 22 I like the brass fitting on copper the problem I see most people use DOT plastic and in time the plastic breaks at the fitting or the mice chews holes in the plastic DOT tubing with both type fitting 

[gus]

I've never had a DOT push fitting leak or come loose.

They must be clean when connected and for easier disconnecting. Sometimes dirt inside the release disc will keep it from moving toward the connection.

[Darkspeed]

What is the correct type of copper tube for DOT air systems?

[Scott & Heather]

^ I'm interested in this too. Btw, this thread is starting to sound like the PEX push connect v.s. Crimp connector threads lol


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[eagle19952]

What is the correct type of copper tube for DOT air systems?

i would not use copper... if you have a frame mounted R-12, feeding a suspension mounted brake can... i have never seen a piece of copper do hat job....
what are you trying to accomplish with copper tube ?

[Darkspeed]

not between moving parts 

my 4106 had all copper between tanks , tanks to valves , pedals to valves, etc..

[eagle19952]

not between moving parts 

my 4106 had all copper between tanks , tanks to valves , pedals to valves, etc..

DOT rubber and nylon is an improvement.. imo