Identify air fitting - Alemite

[abfisher1798]

This is leaking like a sieve from the rear of the FMTV. It was part of the air brake system, see photos.
What is it, and where can I find a replacement?

Thanks!

 

[NDT]

That is your axle vent. There is nothing wrong with it. What has failed is a wheel hub CTIS seal which is pressurizing your axle housing.
Edit: Well you added more pictures. It is not your axle vent.

 

[abfisher1798]

That is your axle vent. There is nothing wrong with it. What has failed is a wheel hub CTIS seal which is pressurizing your axle housing.

That must be it. I figured it was just a vent.

Now I need to find a way to deal with that seal. Is there any way to bypass the CTIS? Or am I stuck with a costly repair?
Thanks!

 

[simp5782]

That must be it. I figured it was just a vent.

Now I need to find a way to deal with that seal. Is there any way to bypass the CTIS? Or am I stuck with a costly repair?
Thanks!

Just unplug the ctis box so it's not operating

It's a simple repair of replacing the seals

 

[abfisher1798]

Just unplug the ctis box so it's not operating

It's a simple repair of replacing the seals

The air leaks out the vent only when I am apply the brakes. Does that mean anything?

 

[simp5782]

That's odd since the brakes
are not connected to anything that puts air into the axle tube.

The air leaks out the vent only when I am apply the brakes. Does that mean anything?

 

[B-Dog]

What you have pictured in the OP is the tractor protection valve. I don't know enough about how it works to tell you exactly why/what air it's supposed to vent. I'd guess it's to allow the valve to shuttle back and forth so I'd guess your leak is probably just a bad oring.

Unless you're going to tow something with air brakes (i.e. utilize the rear gladhands) just get rid of that whole system.

 

[Mullaney]

What you have pictured in the OP is the tractor protection valve. I don't know enough about how it works to tell you exactly why/what air it's supposed to vent. I'd guess it's to allow the valve to shuttle back and forth so I'd guess your leak is probably just a bad oring.

Unless you're going to tow something with air brakes (i.e. utilize the rear gladhands) just get rid of that whole system.

.
abfisher1798 I'm not the expert by any means, but that is a standard TruckPro or NAPA part.
Replacing that valve might be a better option.

Just BE SURE that you take pictures so nothing gets "plumbed" in weird or differently than it is now. There are in and out flowing air tubes and you will have a lot more frustration if you put the wrong "hose" in the wrong place. Don't hesitate to get creative. Different colors of electrical tape or colored wire... Just something to mark it up in your cell phone pictures. Generally the bends in the plastic lines will keep their shape and almost fall back in place - but not always!

The part number for it might even be in the Parts List spreadsheet posted as a "Sticky" in the forum

 

[Ronmar]

Yep, what Bdog and Mullaney said. It is the air brake protecting valve. It controls the airflow to the rear gladhands. It has pri and sec service air applied from the pedal, and trailer air from the dash control valve. That fitting is the vent that helps to release trailer air when you let off the pedal to release the brakes. If it is venting when you press the pedal it has a problem. So either replace it, or as mentioned remove it if you don’t plan to tow air braked trailers or vehicles. t is fairly easy to remove, but there are a few specific steps required to not effect other functions. Here is a vid explaining the parts over the rear axle…

 

[Suprman]

The tractor valve has bad diaphragms. Common issue. There is a rebuild kit for it.

 

[abfisher1798]

Yep, what Bdog and Mullaney said. It is the air brake protecting valve. It controls the airflow to the rear gladhands. It has pri and sec service air applied from the pedal, and trailer air from the dash control valve. That fitting is the vent that helps to release trailer air when you let off the pedal to release the brakes. If it is venting when you press the pedal it has a problem. So either replace it, or as mentioned remove it if you don’t plan to tow air braked trailers or vehicles. t is fairly easy to remove, but there are a few specific steps required to not effect other functions. Here is a vid explaining the parts over the rear axle…

How difficult is it to bypass the valve, temporarily?

 

[Ronmar]

How difficult is it to bypass the valve, temporarily?

It’s not too bad. And it is the same main steps to permanently remove it. In the first pic disconnect the line circled in red and indicated with green and remove the “T” fitting from the side of the load sense valve. Replace the T with an elbow and re-connect the green line(service air in) to the new elbow. No cutting needed, completely reversible. You can get the DOT rated air fitting from someplace like Napa or any truck supply shop.buisness. The crimped ferrule end on the hose and the nut should screw right onto the new elbow.

There is a short brass tube that slips inside the plastic line to support it where the ferrule is compressed. These usually stay in the line you are disconnecting/removing. The new elbow will have one in it. These are press fit into the fitting and you can pull them right out with a pair of pliars, so you can insert the green marked line, which will probably already have one in the line end, right into the elbow port.




For the second step disconnect the line end circled in red, then disconnect the line end circled in green and move it up to the fitting where you removed the line circled in red, and attach it there. There should be enough slack to allow you to circle it around into the port. Again, no cutting and easily reversible.

Thats about it. As long as you don’t activate the trailer air control on the dash, this will bypass that leaking valve. For the lines left disconnected and any unused ports, I would reccomend you bag and tape them to keep the fittings clean and intact.