Air system road side emergency parts

[acme66]

I was asked the other day what I carry in the way of spare parts. The answer is not much. Bunch of tools, grease, a gallon or two of oil, more tools, one wheel bearing and seal set, tools, jack, brake diaphragms, generic wire, tools, electrical splices and some other tools. All pretty standard stuff. One thing I do haul around (and have needed to use it) is some emergency break line stuff. Old brittle lines and vibration do not play well together. Bust a line and lock the spring brakes on the highway and life could get darn inconvenient. I put together a small "kit" of parts, standard stuff in many back woods operations, but things that might get overlooked.

24-36" of 3/8 plastic airline
24-36" of 1/2 plastic airline

(2) 3/8 compression fitting unions/splices ask for DOT
(2) 1/2 compression fitting unions/splices ask for DOT

2 each of 3/8 and 1/2 extra compression ferrules

Alternative splices:
24" of rubber 300psi transmission line 3/8
24" of rubber 300psi transmission line 1/2

Hose clamps, two for each end.

Whole list shouldn't cost you more than $30. Break a line and all you have to do is scrape back the paint of each end and attach the splice. Worst case you have to use both splices and a chunk of your spare hose. It might leak some (scraping/paint will do that) but it will get you to a safe spot to replace the entire offending line.

If this is a commonly posted idea then my apologies, I must have missed it. Drive safe.

Ken

**EDIT**

It was clear that not only did I have some stuff wrong but also that there are some issues with what is plumbing my truck that need to be addressed. I modified the list and the list is still correct but the video is wrong. I am taking the video down, fixing the truck and remaking it to make sure it has the correct information.

 

[juanprado]

Make sure to use DOT air brake fittings not plumbing fittings. They are stamped and the ferrules have an extra ridge in the middle.

 

[Bhpdbrad]

Thank you Ken (acme66) - I have learned a lot about so many different aspects of these trucks from your experiences. Always enjoy watching your videos.

Brad

 

[JDToumanian]

Good idea to carry that stuff, especially if you venture far from home or a NAPA, but aren't those fittings you got meant only for copper? Hardware store compression fittings for plastic require a little brass sleeve that goes inside the tube... DOT air fittings have this built into the fitting, and you push the tube over it. Have you used those fittings on plastic without the sleeve? I'm wondering if you could get them to seal... If they did seal, I wonder if the joint would be at risk for a pull-apart?

Jon

 

[juanprado]

correct, they need the the insert. that insert is part of the sealing and to keep tube from crushing. Notice how the fittings are also stamped.

Plumbing fittings will work in a bind but are not the right stuff.

 

[Jbulach]

They cost more, but push connect fittings are well worth it, in my opinion.No wrenches necessary, able to pull back off and reusable. Tees can be use in conjunction with a short piece of line as a cap as well.

 

[juanprado]

They cost more, but push connect fittings are well worth it, in my opinion.View attachment 673465No wrenches necessary, able to pull back off and reusable. Tees can be use in conjunction with a short piece of line as a cap as well.

I am not familiar with that brand. Are those push lock air brake/dot as there are also push lock for other tubing? Normally they have stampings to id for dot inspection.

 

[Jbulach]

I am not familiar with that brand. Are those push lock air brake/dot as there are also push lock for other tubing? Normally they have stampings to id for dot inspection.

A lot of different brands out there. Commonly called push lock, push to lock, push connect , or stab fittings. Yes, you want the DOT fittings as both are made, same rules apply.

Common non DOT fitting on the left, DOT fitting on the right.

 

[acme66]

I haven't had an issue with sealing but then I have only used them once or twice. The line I carry is thicker than the stuff on the truck, that might be why but then it has all held when I needed it. Worrying about DOT rating on the fitting you are splicing the broken ends of a crispy line back together is silly. Splice ->home ->replace. To be honest a hunk of rubber air line and some hose clamps would do the trick it just isn't as elegant. Now modifying your air system then I would support the need for full DOT spec. That said the push lock fittings look interesting.

Ken

EDIT: All the comments got me thinking so I went back and checked a bunch more. The tank drain lines and right center wheel do not have inserts, left center does. I am sure that is an omission from some time in the distant past.

New line checked out at 7500 thousandths, old stuff w/o inserts about 7000 [FONT=Verdana, Arial, Tahoma, Calibri, Geneva, sans-serif]thousandths. Thicker but mostly in appearance. [/FONT]

 

[acme66]

So it bothered me that I might have this wrong so I just went out and test fit my splices on the line I carry and pulled a few of the truck's air fittings apart to look inside. They fit perfectly, just like I remembered. Nothing on my truck has inserts either in the lines or built into the fittings themselves.*** I am not saying that the non-DOT spec fittings are better just that this was the standard back in the day. I still believe worrying about it for an emergency splice is silly.
Ken

***EDIT: got nervous from this discussion and checked more lines to be sure. My air tank drain lines (easiest ones to get to) do not have inserts, nor does the right hand center axle at the brake can, left hand and other fittings I checked all do. So clearly this was an omission from some time in the past. I will be ordering sleeves or replacing those fittings.

 

[JDToumanian]

....none of the fittings on the truck itself are what we would call a DOT fitting today.

Are you sure? I would have figured if the truck has plastic hoses in the air brake system they would be DOT. And I agree about an emergency fix... Do whatever you need to do to get yourself home.

So what is that hose you carry that is thicker than DOT hose? Unless I'm going far from home, I'm a minimalist as far as what I carry with me, but I do like the idea of some DOT hose and a few push fittings.... Though the hose on my HEMTT isn't brittle, yet.

Jon

 

[acme66]

No it is DOT hose it is just modern DOT hose, just your generic brake air lines. They are however thicker. I have one apart I will go and measure thickness, could be I am crazy.

The new stuff was was 7500 thousandths, the old line I pulled apart was about 7100 thousandths. I don't see that as an appreciable difference, could just be compression from the fittings. Also I wanted to check another so went to a different wheel, guess what... inserts. Yay now I get to check them all. Must have been a Friday when he put that chamber in. Makes me look foolish/dishonest and I hate that. Never trust the truck to be put together properly, eventually I will learn that.

Ken

 

[juanprado]

If you were ever to have a failure and inspected because the lines and/or fittings are not air brake DOT, You are opening up a can of worms.

tubing for air brakes will say DOT fmvss sae J844 or whatever the current spec is. All tubing used to be black and now there are different colors for function. I do not believe color is mandatory, just a convenience for mechanics and manufactures.

I sold parts for 20 years in another lifetime. Not trying to be a nay sayer but educator. Very common mis conception with these fittings. Another tidbit I learned from a weatherhead product class. Air brake tubing is not rated for fuel. Yes, It will work but tubing for fuel carries a different spec. and standards.

Diameter is not crucial as long as it is brake tubing and the insert and ferrules fit snugly on tubing. It is designed to slightly crush to seal and that is why it is strongly recommended that ferrules and inserts are not supposed to be reused. One time hardware.

 

[Csm Davis]

Does anyone have a list of line sizes on a normal 939 series truck?

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[TechnoWeenie]

I would also pre-make a bypass line for the air dryer....