Synflex air line broke at middle pumpkin m1088- not surprised

[Reworked LMTV]

It would appear that the air lines on my M1088 have seen better days. I moved the one on the center pumpkin, and it broke off. Everywhere I look, something rubber or plastic needs help. Southern sun UV eats rubber and plastic. Not unexpected, but will be added to an already long laundry list of tasks. I have a couple of questions.

Is it worth it to go back to Synflex or will any DOT line do? Anybody replace their lines? Wonder how much of each size to order? An special tools to make the lines?

 

[SausageGuy]

It would seem to me a little cheaper to stay with existing style tubing to not have to replace all the fittings but DOT pushloc would save install time. I only have replaced what I had to so far. But everything rubber is failing on mine as well. The diaprahm in a brake check valve under driver crumbled to powder like a broken sweet tart when i pulled it out.

 

[Floridianson]

The reason we should always replace a line with the correct line is not so much the DOT inspector but the lawyers. If the line was meant to have DOT stamped and DOT stamp on the fitting then that is what should be used. If I remember the fittings were thicker walled and have to stand up to a 300 lb. pull and not break off.
Now last time I talked to a DOT inspector while they were doing and inspection they never looked at the line for the stamp or the fitting.
We even talked about the never-seize on the wheel studs. He said he new nothing about it or even looked for it. Once again that going to fall to the lawyers to prove that we did not follow the manufactures simple directions. If the work was being done at a shop and the manufacture call for just a couple of drops of oil on the stud and torque to lets say 500 foot pounds. Now if we followed the simple instructions and did it right seems like it would be hard for the lawyer to prove the shop was at fault and maybe the parts manufacture fault.

 

[155mm]

what size is that hose?

 

[Reworked LMTV]

what size is that hose?

1/4" nylon

 

[Floridianson]

Mine was off too when I got the truck and just had to hook it back up to in gage the axle interlock. Some aux. lines on my 915 do not have the DOT stamped on the line. My air ride seat is one of them. The axle interlock maybe is one of those non critical lines that if it failed it would not affect the brakes. If thinking about it the axle interlock can only come in if we put the transmission in Mode. So if it was leaking we just shut off Mode and not use it till fixed. If you can just find the correct size nylon single layer I think you will be fine.

 

[Awesomeness]

The axle interlock maybe is one of those non critical lines that if it failed it would not affect the brakes.

Perhaps, but what's the cost difference to replace it with the better line? Personally, for the extra few bucks, it's worth it.

 

[Floridianson]

Perhaps, but what's the cost difference to replace it with the better line? Personally, for the extra few bucks, it's worth it.

Yep did not mean cheap water hose from home depot. Synflex come in my forms single and double layer as for the air brake system. I get my Synflex air lines from NAPA or the local truck parts place. I should have said correct truck Synflex line to be clear. Here is some of my Aux. Synflex air lines that are correct but do not have to carry the numbers and DOT letters that is required on the air brake system. The two are for my fifth wheel slide and axle interlock. The other Aux. line feeds air pressure into my air filter housing. They are correct Synflex for truck but carry no numbers or DOT letters. Now the air lines in the one pic on the fire wall that carry some part of the air brake system they must carry the letters and numbers every so many X inches.

 

[simp5782]

I switched all my nylon lines on my 5 ton out to cotton jacket hydraulic type lines. Ordered the bulk hose and all fittings to switch out of Ebay. I used the reusable type fittings for the hydraulic line. 200k miles later they are fine

The nylon lines turn to crisp crap cause the morons spray them and everything under the sun with paint.

 

[Floridianson]

Wes with all you have done and do, plus what you will do I here by bestow upon you "Certified Master Mechanic"

 

[Awesomeness]

The nylon lines turn to crisp crap cause the morons spray them and everything under the sun with paint.

So the paint is what is hardening the lines?

 

[simp5782]

I am the laziest shade tree you will ever meet James. Just ask Jeff Davis.

Nylon tubing is burst tested at 75 degrees. A Hard working air system in stop and go traffic or lots of downhill braking will have hot temps in the system. Much why the compressor discharge tubes are copper for a good length. Out of the compressor you can see 200 degree temps.

Nylon tubing flexes alot. that is why it's used. Cover it with 3 different spray treatments of about 3mils combined and you have an insulated hose now with a air system building up heat. All that coating also decreases its flexibility during articulation. The nylon hose is especially right behind the nut especially during a bend. The carc decreases that bends ability to flex.


The FMTVs use hydraulic hard lines at the wheel brake chambers for that reason of flexibility, durability, and heat resistance

Anyone replacing the chamber lines would be better suited to use double Male jic ends and swap out the chamber fittings with swivel unions for easier install and flexibility. Swivel union fittings are also weaker than the hose so in the event it gets snagged on something or whatever the swivel breaks before the hose gets ripped saving costs