Brass ferrule or Push to lock for air lines

[John Z]

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.

[luvrbus]

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 !!!!!   

[Darkspeed]

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.

[kyle4501]

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. 

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. 

[Darkspeed]

Good luck getting as good a quality copper tubing as was used on your 4106. 

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. 

I thought the long nuts were for copper tubing and the short nuts were for nylon?

[luvrbus]

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

[Iceni John]

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

[luvrbus]

It is reinforced John and it works better with the push in fitting comes in pretty colors also  so you can color code 

[eagle19952]

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.

[luvrbus]

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 

[eagle19952]

no... just feeding the cans 

i just illustrate the durability, the Aeroquip was the worst...

[kyle4501]

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.