Any advantages using brass ferrules and nuts instead of nylon Push to lock fittings for the pneumatic systems?
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
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
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
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 :o
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 . . . ::)
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.
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.
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.
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
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.
What is the correct type of copper tube for DOT air systems?
^ 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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Quote from: Darkspeed on September 23, 2015, 06:31:55 PM
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 ?
not between moving parts :o
my 4106 had all copper between tanks , tanks to valves , pedals to valves, etc..
Quote from: Darkspeed on September 23, 2015, 07:37:24 PM
not between moving parts :o
my 4106 had all copper between tanks , tanks to valves , pedals to valves, etc..
DOT rubber and nylon is an improvement.. imo
I asked this question of the shop foreman where I used to drive. "Absolutely do not use push ins. Their only advantage is saving time up front. They will actually waste time when you have to replace them with compression fittings. Do it right the first time." I liken it to using the push in connectors on 120 elec outlets. I always take the time to use the screw terminals.
They have made a lot improvements in the last 2 years on the push in fitting,I have some of the early one and the new ones no comparison
lol the older stuff is all now that uses the compression or flare fittings and they leak too !!!!!
Is it better to use copper tube in the impossible to access areas? It lasted 55 years on my 4106, I cant see the nylon tube lasting 55 years.
Quote from: Darkspeed on September 24, 2015, 08:39:32 AM
Is it better to use copper tube in the impossible to access areas? It lasted 55 years on my 4106, I cant see the nylon tube lasting 55 years.
Good luck getting as good a quality copper tubing as was used on your 4106. :P
I was very skeptical about the nylon tubing, but it has proven as reliable or more so than the copper.
Wouldn't the tubing used for brakes need to be labeled as DOT approved?
There are certain techniques needed with copper tubing to ensure long term success. (Same to be said for almost anything)
Since the standard has been nylon tubing for 30+ years, I'm using that. I prefer the ferrule fittings with a long nut, but will use push in if that is all that is available at the time - or if I'm too lazy to turn a wrench in a tight location. :o
Quote from: kyle4501 on September 24, 2015, 10:52:06 AM
Good luck getting as good a quality copper tubing as was used on your 4106. :P
I was very skeptical about the nylon tubing, but it has proven as reliable or more so than the copper.
Wouldn't the tubing used for brakes need to be labeled as DOT approved?
There are certain techniques needed with copper tubing to ensure long term success. (Same to be said for almost anything)
Since the standard has been nylon tubing for 30+ years, I'm using that. I prefer the ferrule fittings with a long nut, but will use push in if that is all that is available at the time - or if I'm too lazy to turn a wrench in a tight location. :o
I thought the long nuts were for copper tubing and the short nuts were for nylon?
There are different grades of the DOT tubing not all are equal fwiw,I have replaced it seems likes miles of the stuff where grinding,cutting and welding sparks have landed on it.No matter which nut you use without the stiffing insert it will give you problems,most of the DOT approved fitting has it built into the fitting
To add another wrinkle to this story, I've found that DOT nylon airbrake tubing, at least in 1/4" size, comes in two very different grades. One is plain black plastic, indistinguishable from non-DOT plastic tubing except for it having the DOT specs written on it; the other is a slightly thicker wall (I think, but I've not measured it to be sure), but it has a reinforcing mesh in the plastic. This latter tubing is stiffer, seems to fit in the Alkon AQ DOT push-in fittings more positively, and just seems better overall quality. It is however a lot more expensive! I use the better tubing for brake-related stuff, the cheaper DOT tubing for non-brake things that are connected to the bus's air system, and generic plastic non-DOT tubing for non-critical applications such as the turbo boost gauge.
So far, touch wood (but not manufactured stranded wood products . . .) none of my push-in fittings are leaking at all, but time will tell. I do however take meticulous care when cutting the tubing and making sure it's burr-free.
John
It is reinforced John and it works better with the push in fitting comes in pretty colors also ;D so you can color code
Flip over a 100T lowboy trailer that has seen 40 or 50 trips from Fairbanks to Prudhoe Bay. all gravel and rocks at only 30-35 mph max. mashing and bashing a few 100 rocks per mile......the road flying rocks will beat an under carriage to death.
then look at DOT rubber, copper, Aeroquip and nylon... I can assure you nylon is much more durable. ???
Both my 50 ton and 100 ton lowboys had S/S tubing from the glad hands back to the tank then rubber hose to the brake pods from the relays about 1 ft in length.I don't think I would want plastic tubing for the main supply lines on a lowboy
no... just feeding the cans ;D
i just illustrate the durability, the Aeroquip was the worst...
Quote from: Darkspeed on September 24, 2015, 10:55:35 AM
I thought the long nuts were for copper tubing and the short nuts were for nylon?
Right you are! Thanks for calling my attention to that.
Obviously the information I got from the parts guy was not accurate. It was there in the Parker catalog, plain as day.