M105a2 Air hoses ID?

juanprado

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My trailer brakes locked up when I attempted to tow my m105a2 with the dual hoses hooked up to my m923.

I had the hoses hooked up straight Left driver side to Service and right side to passenger emergency on the m923. I did have the valves open as I tested for air and had changed the glad hand seals to colored neoprene. No leaks when hooked up.

Some have advised me that I should have crossed them. I did check the TM for the m105 and "thought" I had it correct.

Could those with m105's with dual hoses advise me as to which hose is which as I was going to change the relay valve and wonder if it was just "operator" error not hardware failure?

Thanks!

Juan
 

3dAngus

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I can't get to mine right now as the rain outside makes it somewhat prohibitive. I was just wondering if your M923 lines might be crossed, a possibility that became a reality to me with one of my deuces. I'm sure you can figure out how to test that end of it. Normally, right line goes to right line, and left goes to left. I would never bet on it though, any more then I would the color of the hose or the markings of the hose on a M105 trailer. I have seen them many different ways.

I have researched the tech manual and not sure it will really help you. I was hoping to find the complete run for the emergency side vs the service side. I'm not happy with the layout, but I'm sure there is another tech manual somewhere that would make it more clear. Right side or passenger side is suppossed to be emergency side, with the drivers side being the service side, but again, that means nothing based on my personal experience.

http://test.steelsoldiers.com/upload/trailer/TM9-2330-213-14&P.pdf
 

KsM715

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Climb under your trailer and trace the hoses back to the valve. It should be labeled service on one port and emergency on the other. Hook them to your truck accordingly.
 

FormerNewMVGuy

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The hose coming out of the left front of your trailer is the emergency air, which goes to the right rear of your truck. The hose coming out of the right front of your trailer is the service air , which goes to the left rear of your truck.
 

kawkev

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If the color coding is still visible, yellow should be service or brakes, red would be for emergency or for airing up tires if I'm not mistaken. 3d Angus is right about the positions. At least on my deuce anyway. I just acquired one of the converter dollies for towing a 5th wheel type trailer behind the deuce. When I connected it left to left and right to right, it didn't work. I crossed the lines and it worked perfect. So you may want to try crossing them and see what happens. You would think the 923 and the deuce air connections would be similar but then again, was the 105 meant to be towed by the 923?

Just my 2cents
 

3dAngus

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The hose coming out of the left front of your trailer is the emergency air, which goes to the right rear of your truck. The hose coming out of the right front of your trailer is the service air , which goes to the left rear of your truck.
I know it is on some trailers. No argument.
But according to the tech manual and MV hookup pictorials in it, the right goes to the right, and the left goes to the left. I have seem more of them this way then the other, but have seen both.
 

FormerNewMVGuy

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I know it is on some trailers. No argument.
But according to the tech manual and MV hookup pictorials in it, the right goes to the right, and the left goes to the left. I have seem more of them this way then the other, but have seen both.
I own two 105a2 and they are both the same, and so are all the others i've run across....Just sayin
 

3dAngus

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I own two 105a2 and they are both the same, and so are all the others i've run across....Just sayin
Yes, I know, and I completely believe you. Now look at page 2-18 of the tech manual link I provided in post number 2. They are supposed to be straight lined hookup.

We are not always so fortunate to get them hooked up correctly when we purchase the trailers. I am guessing there is some other documentation that contradicts this hookup, and that is why so many of these trailers have the air line hookups reversed.
 

FormerNewMVGuy

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Yes ,i see what you are saying about that picture, I guess the op should take a look under his trailer to see what is what, But i have never seen one different than my two.
I did have a friend who bought a trailer , picked it up with his duece, hooked the single line up to his emergency air, and proceeded to flatspot his tires for a mile or so.....

And then there are the times where, while u park the air leaks down and locks the trailer brakes up....
 

KsM715

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Thats why I said what I said. Who knows what pvt numbnuts did to that trailer when it was in the shop. Whether he painted the right color on the glad hand (or simply installed the right color) or put a new valve under the trailer and paid no attention to which way it was supposed to be hooked up. Trace the lines back and you'll know which hose is supposed to be hooked to emer. and which goesto the service side.
 

rosco

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I whole heartedly agree with all above, especially KsM715's description of shop possibilities. Commercial Civi vehicles are plumbed : Left to Left; Right to Right. That is pretty simple, and I would try to keep things that way. Tracing the lines to that Relay/Emergency Valve is simple too. Those are civi valves, and should say right there at the aiir line point of attachment: Emergency or Service. That would be the place to most easily straighten out the cross over. The early 105s had no air storage or R/E Valve, so the aiir line just happens to be often on the right side of the trailer, but goes to the Left/Service side, of the truck. Hey.... nothing is "Fool Proof".
 

juanprado

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Thanks for the advise! Trailer is not at my house but I will check it out to see where the hoses are plumbed. I do have a new valve and it does have the markings cast into it quite clearly so I imagine the original one also will be marked or i will use the new one for a reference.

I believe the m923 is plumbed correctly according to the tm and it is painted along with metal triangle stamped tags on the bulkhead fittings. I also had the unfortunate pleasure of being towed and they did use the front glad hand and all was good there.

I will report what I find when I can inspect the trailer as it has been a rainy moonsoon here in the banana republic. :)
 

juanprado

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Well, I finally got under the trailer. The ports under the valve are labeled "delivery" on both sides on the bottom but I could not see the top of the relay valve. The new valve is clearly marked with the Driver's side = "Emergency" & Passenger's side = "service" on the top so in this case the TM is not correct (3rd time in the past 10 days I have found issues with tm's) and since the M939 are opposite sides, they "should" be crossed.

Good news is probably that I don't need a new relay valve but already invested in one. :-(

I also flat spotted the tires for no good reason :-(
 

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goldneagle

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Well, I finally got under the trailer. The ports under the valve are labeled "delivery" on both sides on the bottom but I could not see the top of the relay valve. The new valve is clearly marked with the Driver's side = "Emergency" & Passenger's side = "service" on the top so in this case the TM is not correct (3rd time in the past 10 days I have found issues with tm's) and since the M939 are opposite sides, they "should" be crossed.

Good news is probably that I don't need a new relay valve but already invested in one. :-(

I also flat spotted the tires for no good reason :-(
Don't feel too bad about it. It happened to me when i recovered one of my M105 trailers from Ft. Polk. I put them on straight and they locked up as soon as i left the gate to the yard. Had to jump out and disconnect them. Had to drain the air out of the tank to release the brakes. Decided to leave the hoses off since the trailer was empty anyway. Found out later from Wreckerman that I had the hoses on wrong! Now I know to cross them when hooking up. It was the Deuce doing the recovery in that case but the M923 is the same.

(maybe I can use that valve to make the brake work on the M109 trailer. MDMORGAN never finished reconfiguring the brake system on it.)
 

rosco

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JP: Those RE Valves, are set up to deliver air to two axles at once. I suspect that you were looking at the "delivery" side of the valve, and not the Service/Emergency ports.
 

juanprado

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Dell,

I did not drive/tow the trailer today but feel having hooked up the hoses "wrong" was the issue. The air was applying the brakes without using them. Once I drained the tanks and disconnected the hoses, It towed fine. The trailer was real cherry and I suspect real low miles/usage. Not sure when the next time I will tow it, probably in late May.

Zev,

Midland/haldex in the online catalog recommends it for only air/hydraulic. They specifically do not allow it for full air brakes. If that is your set up, We can talk :) You could get the air tank and Pancake booster with master cyl from Tim along with the bulkhead fittings. All it would take is hydraulic steel brake lines and nylon air tubing/fittings. The not easy part would be if there is an equalizer valve/block for the brake fluid lines for the axles or do they just use a "t" on each side. Don't know deuce specifically, just parts. :)

It is a midland A52485-2; military nos 2530-00-021-2366
 

WingCO

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My air lines are marked to cross over . . . on the trailer it has the sources marked 'service' and 'emergency', and on my M35A2C they are reversed, i.e., on differenct sides, 'emergency' and 'service'.

Now can someone tell me where to purchase the air hoses to replace one? I've checked with all of the 'known' surplus dealers and none of them have the correct NSN. I believe I will have to purchase stock hose and replace the one that has a pinhole in it. What is the correct ID or OD to use?

Thanks, I'll hang up and listen for your response.
 
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