Axle vent/pressure release valve

[rtadams89]

I have seen the numerous threads about these valves and the solutions to ones that stick. Most of the threads seem to end with a discussion of replacing the valves with tubing that runs to somewhere like the air intake. This is a great idea and probably where I will end up, but I have a specific question about an alternative option which I have not been able to find an opinion about. I have found a number of places that stock sintered bronze breather valves (example from Amazon: https://www.amazon.com/PneumaticPlus-BVS-18-Sintered-Bronze-Breather/dp/B005OOA6GU) at a price of roughly $1/valve. These claim to let air pressure equalize but prevent debris from passing. Will these types of breathers keep water out? Will these provide at least an equal level of performance and protection as the stock axle bleeder valves?

 

[fsearls92]

I can't say if those will keep water out, but would Definately recommend doing the central vent upgrade. It is really cheap to do and will keep you from blowing axle seals. I personally wouldn't mess with those vents, if they don't keep water out you will spend more in fluid for one axle than all the parts for the central vent system.

 

[SCSG-G4]

My personal opinion is that they will NOT keep water out if placed directly on the axle. However, it they are placed high up on the frame with tubing running down to the axle point, they have a much greater chance of staying dry. How often do you take the truck swimming, how often do you drive in heavy rains that will splash a lot of water up into the underside of your truck (thing going through standing water, from little puddles to small lakes). Most folks tend to run the tube all the way to the main air filter just so the air stays dry in the tube. Might just be a case of penny wise and pound foolish!

 

[red]

Those filters do not stop water. Quick splash they do fine but if they get submerged water does get through them.

 

[silverstate55]

I ran all mine up to a central port near the air filter, then capped it with a small fuel filter to keep dust/particulates out. I thought about terminating the vent hoses in the truck's air filter housing, but then I became worried about creating a vacuum inside the axle housing....

So far, so good...axle seals are holding up well, and gear oil appears to be healthy. YMMV.

 

[rustystud]

I ran all mine up to a central port near the air filter, then capped it with a small fuel filter to keep dust/particulates out. I thought about terminating the vent hoses in the truck's air filter housing, but then I became worried about creating a vacuum inside the axle housing....

So far, so good...axle seals are holding up well, and gear oil appears to be healthy. YMMV.

This is the best way to do it. You don't want to actually connect to the air filter as just like "silverstate55" said you will draw a vacuum in the differentials and actually start to draw water in from the seals themselves. The best way is to run "all" the vent lines to a central location and have that mounted as high as you can on the cab. I mounted mine on the top of the firewall near the air filter. I don't plan on ever going that deep in water. Just maybe up to the engine block, like crossing a large stream would do.

 

[orren]

The main idea of a centralized venting system, as I understand it, is to be able to
apply low pressure air to the axles, 3 psi, and other components whenever you find
yourself entering water of some depth. This should minimize the amount of
water/debris getting into things.

If plumbed right the vent system still can be vented to the outside when not
in water.

 

[SCSG-G4]

The main idea of a centralized venting system, as I understand it, is to be able to
apply low pressure air to the axles, 3 psi, and other components whenever you find
yourself entering water of some depth. This should minimize the amount of
water/debris getting into things.

If plumbed right the vent system still can be vented to the outside when not
in water.

That is what the USMC deuces have, a pressurized system which includes the clutch/pressure plate (and a permanently mounted drain plug on the bell housing - no alternate location). I have the remains of one on my M-36.

 

[orren]

That is what the USMC deuces have, a pressurized system which includes the clutch/pressure plate (and a permanently mounted drain plug on the bell housing - no alternate location). I have the remains of one on my M-36.

Where on the bell housing is the pressurized system fitting mounted? Is there a plug or something on top of it?

Also, is there a pressurizing fitting on the transmission?

Thanks

 

[Floridianson]

Funny but the axle vent that is there holds a small amount of pressure in the axle. To use one of them just higher up seems like a good idea.

 

[73m819]

The problem with using the vents valves anywhere is the vent itself, the vent allows pressure build up, after a certain pressure is obtained the excess to be expelled, now hear is the problem, the air expelled from the vent contains oil in the form of a oily mist, the oil is a natural byproduct of HOT oil. this mixes with the air expanded by the hot oil and metal, this forms the OILY MIST, as the mist moves past the vent seal, some oil is left on the vent seal, dust sticks to the seal, after time this dust buildup causes the valve to stick a bit (holding more pressure ), this only keeps getting worse, more stick/more pressure, at some point, the stuck vent valve holds enough pressure to push past a seal (leak).

A secondary issue with the vent valve is that it is ONLY a one way valve (out), AFTER the excess pressure is expelled and the oil/metal cools down, the air contracts due to the cool and causes a VACUUM which draws air though a seal to correct the vacuum, this air draw brings IN dust with it and in turn wares on the seal sealing surface (leak) AND ALL the internal contact surfaces.

So the bottom line is GET RID OF THE VENT SEAL, the ONLY reason for the bit of pressure in the first place is to keep water out during a amphibious landing (same reason for the grease hubs, these can be run with water in them till the hubs are pulled and the bearings repacked which according to the -10 is as soon as possible ).

Just some food for thought -- The aftermath of a leak caused by a sticky vent valve in the military is a visit to the motor pool shop, the fix does not cost the military a cent because somebody else (tax payer ) pays for the fix,

 

[73m819]

Where on the bell housing is the pressurized system fitting mounted? Is there a plug or something on top of it?

Also, is there a pressurizing fitting on the transmission?

Thanks

This is all part of the FULL fording kit install. A member CRANE TRUCK did a FULL fording install, he still had a bit of water intrusion.

 

[M35A2-AZ]

Central vent system is the way to go, cost about $40 for the three axles. I added my transfer case and transmission on my Deuce.

 

[Floridianson]

The problem with using the vents valves anywhere is the vent itself, the vent allows pressure build up, after a certain pressure is obtained the excess to be expelled, now hear is the problem, the air expelled from the vent contains oil in the form of a oily mist, the oil is a natural byproduct of HOT oil. this mixes with the air expanded by the hot oil and metal, this forms the OILY MIST, as the mist moves past the vent seal, some oil is left on the vent seal, dust sticks to the seal, after time this dust buildup causes the valve to stick a bit (holding more pressure ), this only keeps getting worse, more stick/more pressure, at some point, the stuck vent valve holds enough pressure to push past a seal (leak).

A secondary issue with the vent valve is that it is ONLY a one way valve (out), AFTER the excess pressure is expelled and the oil/metal cools down, the air contracts due to the cool and causes a VACUUM which draws air though a seal to correct the vacuum, this air draw brings IN dust with it and in turn wares on the seal sealing surface (leak) AND ALL the internal contact surfaces.

So the bottom line is GET RID OF THE VENT SEAL, the ONLY reason for the bit of pressure in the first place is to keep water out during a amphibious landing (same reason for the grease hubs, these can be run with water in them till the hubs are pulled and the bearings repacked which according to the -10 is as soon as possible ).

Just some food for thought -- The aftermath of a leak caused by a sticky vent valve in the military is a visit to the motor pool shop, the fix does not cost the military a cent because somebody else (tax payer ) pays for the fix,

Guess anything can fail but I have never had a problem with that simple vent. I had more trouble with the open vents on my civi dump truck getting mud caked on them and that could build up lots of pressure. When on a walk around I just gave them a couple of spins to clear them for the day. We talked about this a lot and as I said before when the axle does cool because you have shut down for the day where is the dust coming from as the truck is not moving on a dusty road. I don't see the problem with the vent for water intrusion but bad seals and people that thing these trucks are water proof. As all ways do what you feel is correct. Now you can fool yourself and have the best fording system but you still better check everything after a deep ford or you will have problems.

 

[st8drumz]

Would those of you who have done the relocation mods mind posting pics? I have relocated the 3 axle vent caps via hose to the top rear of the cab on my A2 and was told by a vet at the O'Reilly's parts counter that they also turn them down. I have yet to do the transmission and transfer case. If the options listed here are better, shared thoughts would be great. Thanks!

 

[Valence]

I couldn't find the original thread that these pictures were in. I did mine just like Peashooter:
http://www.steelsoldiers.com/showth...Build-Thread&p=1546640&viewfull=1#post1546640

I used 1/4" air brake line to vent all 3 axles, transfer case and transmission. On the rear two axles I followed the flexible brake line and joined the two separate vents at the same location. So I ran a total of 4 lines to a manifold mounted on the firewall, one line for rear axles, one for transmission, transfer case and front axle.

 

[Floridianson]

Clean install there Valance. Now don't get me wrong all for making the truck water resistant just water proofing would be the trick. Myself to many times water/mud or fording has left me working on the truck in some way or another.