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Replacing copper air lines in an 809 series

Ajax MD

Ajax MD

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A couple of simple questions:

  • How difficult is it to replace the hard air lines on an M813? I know that there are new, modern materials approved for highway use. Are they easier to work with than the copper lines and fittings?
  • Is this something that should be a preventative task? How often do the hard lines fail? Is the mode of failure typically "catastrophic" or is it more of a slow leak that gives warning?
With these big trucks, I'm all about safety but I'm also about not tearing stuff up needlessly.
 
Mullaney

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Ajax MD said:
A couple of simple questions:

  • How difficult is it to replace the hard air lines on an M813? I know that there are new, modern materials approved for highway use. Are they easier to work with than the copper lines and fittings?
  • Is this something that should be a preventative task? How often do the hard lines fail? Is the mode of failure typically "catastrophic" or is it more of a slow leak that gives warning?
With these big trucks, I'm all about safety but I'm also about not tearing stuff up needlessly.
Click to expand...
.
Vibration is the killer for the copper lines. That problem is exacerbated if there are loose supports for those copper lines. Where somebody removed a support and the tubing flops around and that sets up a failure.

I am not an expert, but if you use your house for an example: The copper plumbing is well supported. It keeps the tubing from bouncing around when you turn the water off and on. The house doesn't move, but the pipes can if they aren't secured. Same with the truck. My house is 40 years old since it was gutted and replumbed. The copper pipes in that situation are perfectly good...

There are DOT Approved nylon lines for truck air systems. Those plastic lines need to be anchored to the frame the same way as the copper. EVERYONE HAS AN OPINION. Mine is that if you carefully inspect the copper and don't see rub marks on it, chances are it will last longer than you.
 
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BKubu

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I once lent an M35A2 to a friend who wanted to towbar another M35A2 out of a local base after his purchase. Being younger and dumb(er), I agreed to let him use my truck and towbar. The recovery was a success. Upon pulling into my yard after he dropped off his truck, he hit the brakes (I was standing nearby). I noticed a stream of brake fluid shoot out from underneath the truck. Upon inspection, one of the brake lines had failed. Fortunately, it failed after he got back. I replaced the rusted line with nickel copper brake line purchased at Napa. I also inspected the rest of the brake lines and found they looked OK (from what I could tell).

I sold the towbar.
 
US6x4

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I just replaced my air horn copper line with a new line from Napa that I formed up and the original M813 copper tube was almost twice the wall thickness as the new line. I imagine you can order different wall thicknesses but it looks like the original is much beefier than a typical replacement.
 
Mullaney

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US6x4 said:
I just replaced my air horn copper line with a new line from Napa that I formed up and the original M813 copper tube was almost twice the wall thickness as the new line. I imagine you can order different wall thicknesses but it looks like the original is much beefier than a typical replacement.
Click to expand...
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I did a quick search and apparently with (rigid) copper plumping pipe, there is a Schedule 40 and a Schedule 80.
All I know is that the different numbers relate to wall thickness. 80 is thicker. Outside dimensions are the same.

So I don't know enough to be really smart though.
I think we have one in our midst that can speak to copper pipe thickness.
Will PM him and hopefully get a "weigh in" on the question.
 
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G744

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One nice thing is the copper and Nylon can use (or reuse) the same fittings, as the OD is the same. The new fittings sold for use with plastic lines have a slightly different outside dimension, but either works.

One will have to buy new barrels for the job, as the old ones will be crimped on the used line.

I've swapped out some in hard to reach places, and just used the newer 'nuts' on the old brass. They thread right on.

Dennis
 
marchplumber

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Rolled copper "soft copper" comes in different wall thicknesses. M is the thinnest. L is standard. K is for water service and H.D. applications. Original piping was probably type L copper. Replacement sounds like M. The O.D. are the same for all...............wall thickness is vastly different.

Hope that helps a bit.
 
M37M35

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Mullaney said:
.
Vibration is the killer for the copper lines. That problem is exacerbated if there are loose supports for those copper lines. Where somebody removed a support and the tubing flops around and that sets up a failure.

I am not an expert, but if you use your house for an example: The copper plumbing is well supported. It keeps the tubing from bouncing around when you turn the water off and on. The house doesn't move, but the pipes can if they aren't secured. Same with the truck. My house is 40 years old since it was gutted and replumbed. The copper pipes in that situation are perfectly good...

There are DOT Approved nylon lines for truck air systems. Those plastic lines need to be anchored to the frame the same way as the copper. EVERYONE HAS AN OPINION. Mine is that if you carefully inspect the copper and don't see rub marks on it, chances are it will last longer than you.
Click to expand...
My thoughts too.
I'm sticking with copper on my deuce.
 
Big Tom

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Ajax MD said:
A couple of simple questions:

  • How difficult is it to replace the hard air lines on an M813? I know that there are new, modern materials approved for highway use. Are they easier to work with than the copper lines and fittings?
  • Is this something that should be a preventative task? How often do the hard lines fail? Is the mode of failure typically "catastrophic" or is it more of a slow leak that gives warning?
With these big trucks, I'm all about safety but I'm also about not tearing stuff up needlessly.
Click to expand...
Well my Cooper line just broke at the compressor outlet Friday on the way to graves mountian rally , was able to cut it clean and get it back together to get here , that line takes the biggest stress of all , don’t know if plastic line would take the heat there it gets hott. There is a splice by steering g box stoped at Lowe’s got 1/2” line and furrels replaced that section and when I get home going to do my other duece as a preventive measure

Big Tom
 
Jbulach

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They make a braided stainless line for the air compressor outlet. Believe it or not they are still some type of plastic on the inside. They handle the flex and vibration much better than coper.
Coper lines tend to brake at the flare or ferrule and no real good way of predicting or inspecting the connections that I know of.
 
MyothersanM1

MyothersanM1

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My M818 has been fully converted to dual circuit air brakes with s-cam rears and M939-series wedges on the front. Plumbing is mostly DOT push-to connect fittings and NT100 nylon air brake tubing. The existing fittings can be used with NT100 if you use the specific tube sleeves, nuts and inserts.
IMG_0334.JPGIMG_0341.JPGIMG_0347.JPG

I use SAE J1402A hose and fittings to the brake chambers.
DSC_0022.JPGPlumbing and Relay Valves (79).JPG

The air line from the air compressor to the air dryer is Teflon lined braided steel with AN fittings.
Plumbing and Relay Valves (68).JPGPlumbing and Relay Valves (69).JPG
 
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Autocar

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If you replace any fittings, make sure they are DOT fittings. They are different than standard brass fittings. The nuts are longer to support the tube for vibration and the nut threads are different so that you can't interchange with standard brass fittings. Most likely have to go to a heavy truck parts supply house to get them.
 
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