Pressurized Axles?

[4x4e350]

I was checking the fluid condition and levels on the 5 ton yesterday, all three axles look like the fluid was just changed, good news!
Anyway, as I removed the plugs on the axles, all three axles released pressure as I was turning the plug out. It wasn't just a little amount, it seemed to be atleast a few psi. I would'nt of thought much about it, but it just seemed odd to me that all axles had the pressure.
All my axle vents are just the little nipples with a cap on top, so no hoses or special fording kit. Do the axle vents have some type of check valve, so they wont release pressure till a certain amount of psi is built up? Or should I remove all the vents, and make sure they aren't plugged?

 

[cranetruck]

The breather valves will open for 1/2 psi or so of pressure from within the axle housing. Here are a couple of references.

 

[4x4e350]

WOW, your quick!
Thank you, great information.

 

[cranetruck]

You are welcome...all repeat info these days...

 

[4x4e350]

You are welcome...all repeat info these days...

Sorry, I did a few searchs, and all I could find was pressure from fording kits.

 

[cranetruck]

Sorry, I did a few searchs, and all I could find was pressure from fording kits.

No problem, I don't mind, got nothing better to do.

I prefer the google search, just add "steelsoldiers" (see image).

 

[Maverick1701]

my valves were so gummed up they wouldnt function. I had to clean them pretty well...eventually I just made my own vent lines and solved the problem.

 

[armytruck63]

I prefer the google search, just add "steelsoldiers" (see image).

Now that is a useful search tip. Thanks Cranetruck!

 

[BadMastard]

One quick note, I had something similar on my M35A3, BUT it wasn't pressure, it was vacuum. The cap worked beautifully on venting, but not so good on allowing air back in. Just a thought.

 

[73m819]

One quick note, I had something similar on my M35A3, BUT it wasn't pressure, it was vacuum. The cap worked beautifully on venting, but not so good on allowing air back in. Just a thought.

This is the problem with these valves, thay ONLY work one way, pressure out, sucking crap in, it is a lot better just throw all 6 away, install hose bibs, tees, then use vaccum line run to the fire wall with a cheap gas filiter on the end

 

[cranetruck]

This is the problem with these valves, thay ONLY work one way, pressure out, sucking crap in, it is a lot better just throw all 6 away, install hose bibs, tees, then use vaccum line run to the fire wall with a cheap gas filiter on the end

Went a bit further and hooked all of them to the low pressure regulator, so everything can either be vented or pressurized...

 

[abh3]

What a great idea. My old Landrover always seemed to get water in the axles when wading after some driving but not so much cold, I always wondered if the axles cooling off rapidly in the water created a vacuum that sucked the water past the seals. Eventually I just did away with the vent thingies and ran hose up to the aircleaner to avoid mud plugging vents/hoses altogether, dirt-dauber problems, etc...

 

[cranetruck]

About the one-way breather vents, don't know where I have seen it, but there are specific instructions about letting the axles cool off before entering water for that exact reason (sucking water through seals when the hot air cools off).

 

[cranetruck]

More fording info...

 

[kastein]

I'd love to see a cheap air pressure regulator that can put out ~1/10 of a psi of air for pressurizing the axles, transfer case, transmission, etc... why? If I find myself in deep water I would rather be blowing a tiny bit of lube out than taking any amount of water in. Haven't been able to find any regulators that will go low enough to not blow out every seal though.

 

[Squirt-Truck]

McMaster-Carr sells regulators that will meet your <1/2 psig requirement. They go up to 5 psig and are fully adjustable.

 

[cranetruck]

I'd love to see a cheap air pressure regulator that can put out ~1/10 of a psi of air for pressurizing the axles, transfer case, transmission, etc... why? If I find myself in deep water I would rather be blowing a tiny bit of lube out than taking any amount of water in. Haven't been able to find any regulators that will go low enough to not blow out every seal though.

You will need more than 1/10 psi to keep the water out. Pressure increases by about 1/2psi/ft... The pressure for the deuce should be about 3 psi.

 

[jaxsof]

I have mine set at about 3 1/2 - 4 psi, Trans and transfer get the pressure too

 

[orren]

Fording with alternator.

Thanks for the info. What do you do about the alternator when
in deep water?

Thanks, Orren

I have mine set at about 3 1/2 - 4 psi, Trans and transfer get the pressure too

 

[cranetruck]

Thanks for the info. What do you do about the alternator when
in deep water?

Thanks, Orren

Nothing, the electronics is protected by a gasket. Fording is not supposed to take place for a long period, it's over in a matter of minutes, so if the alternator doesn't produce during that time, no harm is done.
The older, generator regulator system was water proof and for vehicles designed to swim (typ m656), the alternator was pressurized with air like the axle housings etc.