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Axle bellows

Sterlingfire said:
Do you know of anyone not having luck with 9" diffs and bellows?
I wonder if a loose mesh will create more airation? Maybe less heat, at first, but fills with air and that's what causes the bubbling out the breather??
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I don't know anyone running a 9" OR anyone running a bellows. So no help there.
 
I have one on my ft diff. Its got some pin holes in it so it can vent any excessive pressure it it gets too hot or my air locker starts leaking some. Never really been a issue.
 
The TG bellows become brittle and crack on the creases, I threw them away and went Standard breathers on 3/8" fuel line.
If I get water this high I have other problems.
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ThePanzerFuhrer said:
Why are we worrying about this anyways waterhead?
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Well I wouldn’t say I was worried, but it’s funny how according to that thread, the military has been doing this for 50 years, but we have some how lost this technology. My main point was I don’t think the small bellows has any value at all. I thought someone would prove my point.

I still wonder how the tail rotor gearbox and my lawn mower gearbox is just plugged and don’t leak. Both are small compared to a diff, but I don’t really know why that makes a difference. If you heat a sealed 10 gallon container and a 1 gallon container, will the 10 gallon develope more pressure? I rather doubt it.

94toytruck said:
I have one on my ft diff. Its got some pin holes in it so it can vent any excessive pressure it it gets too hot or my air locker starts leaking some. Never really been a issue.
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When you say this, to me, you are running a vent. The fact that you have some floppy rubber on it doesn’t really change anything. Do you submerge your axles very often? Have you checked for water? I don’t suppose much water gets in an axle anyways. I’m beginning to think the vents up to the frame are not necessary. Just have a small hole on the axle.

When I was in my early testing of my HEMTT, I never hooked anything to the vent tubes. I had both axles submearged for probably 20 minutes several times. I didn’t care because I knew I was going to regear. When I opened them up, I don’t remember any water. (Could be the vents were clogged)
 
WaterH said:
When you say this, to me, you are running a vent. The fact that you have some floppy rubber on it doesn’t really change anything. Do you submerge your axles very often? Have you checked for water? I don’t suppose much water gets in an axle anyways. I’m beginning to think the vents up to the frame are not necessary. Just have a small hole on the axle.
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They are pinholes man, nothing crazy it's just so it doesn't blow off if there's a issue. If you've ever been around on of these they will expand and contract if the unit is completely sealed. Mine literally will stay puffed out cause it's got a little pressure inside at the end of the day and by the time I'm home it's just back where it normally is. I don't go out of my way to submerge them but yeah they get submerged. No water in my diff since running a bellow on it but I did have water in my wheel bearings. I only have one on my front axle, my rear axle is extended,

I ran a normal stock vent BITD on my Toyota axles, they would get water in them pretty easily. I just extended those with hose to run up above the water level.
 
No one mentioned contraction and suction. Dunk a sealed hot axle or bearing in the water and it will suck water through the seals. A bellow would need to be big enough to contract way faster than the time to heat up and expand.
Once you go past bellow capacity, vented lines with goretex breathers is an option.
Another option is to use a low pressure 5psi regulator to purge boxes and pressurize so water cannot get in. Regulator also needs to be a venting style so pressure doesn’t go above 5psi.
You could probably use a fixed orifice or needle valve and a low psi relief valve. An aquarium pump might even have enough pressure to work. Or a small 1gpm diaphragm pump ex. weed sprayer pump, they build low air pressure.
 
My front HP44 used to burp oil when it got hot. I'm not sure if it was overfilled a bit due to an aftermarket cover with a higher fill hole. I also may have used the vent fitting hole for the ARB line and relocated the vent fitting to somewhere that saw oil thrown off the ring gear, not sure on that.

I put one of these mounted next to the radiator and no more puking. Not sure if it just needed a little space to expand, or the fluid level came down enough that it quit puking oil out but I'm happy now.

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HYDRODYNAMIC said:
No one mentioned contraction and suction. Dunk a sealed hot axle or bearing in the water and it will suck water through the seals. A bellow would need to be big enough to contract way faster than the time to heat up and expand.
Once you go past bellow capacity, vented lines with goretex breathers is an option.
Another option is to use a low pressure 5psi regulator to purge boxes and pressurize so water cannot get in. Regulator also needs to be a venting style so pressure doesn’t go above 5psi.
You could probably use a fixed orifice or needle valve and a low psi relief valve. An aquarium pump might even have enough pressure to work. Or a small 1gpm diaphragm pump ex. weed sprayer pump, they build low air pressure.
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That would definitely work and the vent would probably never get clogged.
 
bunk said:
Will it hold oil in?
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I don't think it would stop oil on a roll over but it would probably slow it down a good bit. They both use 1/4 air brake hose and push lock fittings.
YJLOPES said:
My front HP44 used to burp oil when it got hot. I'm not sure if it was overfilled a bit due to an aftermarket cover with a higher fill hole. I also may have used the vent fitting hole for the ARB line and relocated the vent fitting to somewhere that saw oil thrown off the ring gear, not sure on that.

I put one of these mounted next to the radiator and no more puking. Not sure if it just needed a little space to expand, or the fluid level came down enough that it quit puking oil out but I'm happy now.

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Same thing as my 14b has and works well.
 
YJLOPES said:
My front HP44 used to burp oil when it got hot. I'm not sure if it was overfilled a bit due to an aftermarket cover with a higher fill hole. I also may have used the vent fitting hole for the ARB line and relocated the vent fitting to somewhere that saw oil thrown off the ring gear, not sure on that.

I put one of these mounted next to the radiator and no more puking. Not sure if it just needed a little space to expand, or the fluid level came down enough that it quit puking oil out but I'm happy now.

1699802982990.png
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The hose on them is to small. The air bubbles push the oil out instead of going around it. That just let's the bubbles escape before it pukes. They work well.
 
JR4X said:
Tried the bellows on my RockJock 60’s in my old race car and it would blow the pinion seal out of the housing and dump the gear oil out. The surface area on the seal housing is huge because one of the big things about the RJ is using the same big pinion bearing on both sides of pinion. No seal retainer and none of the aftermarket billet or forged yokes have the dust cover. Axles build enough air pressure from heat expansion to just push the whole seal out of the pocket.
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On the 9/10" I always put seal protectors on them. It's just a flat plate bolted to the housing which the opening about .050 bigger than the pinion. This keeps the seal in and the bat wire out of it. Not sure there's enough beef around the seal on the RJ's to tap some 10-32ish holes. But it was a life saver several times. The floater hubs also get them.

The yokes usually get a flange welded on them too as extra protection.
 
ThePanzerFuhrer said:
Lol he picked the wrong axles/didn’t build them correctly for submersion.
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He picked 05 Superduty axles because they're pretty perfect for the build in every other way.

I get the allure of a bellows. Just "do math" and size it right and you have nothing to worry about, theoretically. Especially for rigs that will sit on their roofs.

In reality hoses and breathers is just an all around more flexible and reliable option. They don't change how they work based on how cold the rubber is. They don't go out of spec because your oil level is too high/low, etc, etc.
 
arse_sidewards said:
He picked 05 Superduty axles because they're pretty perfect for the build in every other way.

I get the allure of a bellows. Just "do math" and size it right and you have nothing to worry about, theoretically. Especially for rigs that will sit on their roofs.

In reality hoses and breathers is just an all around more flexible and reliable option. They don't change how they work based on how cold the rubber is. They don't go out of spec because your oil level is too high/low, etc, etc.
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The problem he’s gonna have is no matter what he does he’s still gonna get water in the oil after dunking them. The oil seals that keep the oil in will not keep the water from getting into the axles. They are not designed for pressure/water. Just because the axles are sealed keeping the oil in does mean they are sealed from keeping the water out when submerged . 2 way, way different animals.

He wants to pressurize the axle to keep that from happening. The seals are not designed for that either. He would have to do some substantial modding to make that work. Hence the comment these are not the right axles for what he wanted to do, bellows no bellows plugged not plugged ect.

Now if waterhead would put in face sealing seals like my loader axles and excavator final drives have that would be completely a different story.

Seals like this Mechanical Face Seals | Heavy Duty Seals | Trelleborg
 
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I run my junk through water all the time through water holes that swallow 40s.

3/8 fuel line and a filter... How more fuckin simple can you get.

Never had any water in my 14 bolt, nor my 60.

The Dana 44s before hand, the rear would weep a little bit in.
And the hub seals on the 44 were worse than the 60 for letting water in.

If you're axles are really hot when you hit water you're going to suck water in regardless. Like going from road driving temp into a water hole.

You drive your shit on the road, those bellows will never keep up with heat expansion.

On a slow trailered Crawler I'm sure they'd be fine.

I've had the hose on my 14 bolt crack once. Noticed dripping oil out the fitting after 3.5 hour drive, took 10 seconds with a knife to unscrew hose clamp, cut 1" off and put it back on.


This thread is kind of dumb...

Your tiny little mower box and Heli tail rotor likely have far far less rotational aeration of the oil created by hypoid gears and half the gear being submerged in the oil and it being slung friggen everywhere by the ring gear.

Therefore,

Crawler yes they'll work
Road drivin' rig nope.


But by all means prove everyone wrong and put your 1/8 or 1/4 pipe plug in.
 
He doesn't need to pressurize the axle. What he needs is zero relative pressure. If he just ran a normal catch can and vent system with the filters/vents dumping into a sealed box/manifold that's supplied a tiny bit of boost air (like a 3/16 or 1/4 fitting) and has a decent size outlet (like a 1/2 hose) that's run down by the axles then that should do the job without pressurizing anything to a pressure beyond whatever the pressure at the outlet of the big vent hose is (which would reflect water pressure at the depth of the axle when submerged and be nearly atmposhereic the rest of the time because the outlet is so much bigger than the inlet).


Kinda like how some of the old .mil engines had a hose on the crankcase breather that you'd drop down low like the draft tube so that the blowby would pressurize the engine for water crossings.
 
Sterlingfire said:
Do you know of anyone not having luck with 9" diffs and bellows?
I wonder if a loose mesh will create more airation? Maybe less heat, at first, but fills with air and that's what causes the bubbling out the breather??
Click to expand...

The 9" creates more internal pressure due to the lower pinion and high tooth engagement. You'll also find the high pinions tend to create more internal pressure.

Racing and mild trail wheeling are two completely different ends of the spectrum, with everything else falling in between.

Look under desert race trucks to see how big their vents are. Many of them are even running dual vents.

On any axle, the trick is to allow the axle to breathe, it needs to easily vent pressure out, but it also needs to suck air in.

Think of a hot axle dropping into a cold water crossing or mud hole..... That axle is going to cool off rapidly, causing it to contract. It's going to want to suck air in to equalize. If your vent isn't big enough or it's clogged, it will pull in past your seals (axle and/or pinion). If your axle is under water, guess what it is sucking in? Yep, water.

This is why you hear reports of people claiming everything is new, everything is sealed up perfectly, but they still get water in their axles. Especially common in people who run in the mud all the time.

Proper venting is an absolute necessity when running Air Lockers. When you see someone spitting oil out of their solenoids, it's often because their axle housing is over pressurizing and instead of venting out the vent, it is venting out past the seals in the Air Locker.

The keys to proper axle venting:
  • Run a decent sized vent, go 5/16" minimum all the way through, no neck downs.
    • If you are going fast, go bigger, 3/8" minimum, 1/2" or dual 3/8" would be better.
    • If you're running a 9/10" go 3/8" minimum.
  • Relocate vents from the axle tubes to the diff center, that's where the majority of the pressure is created, vent it there.
  • Install a small splash shield over your vent hole on the inside of the axle to keep oil from being splashed into the vent tube. Look inside a Toyota axle for an example.
    • This is not an optional thing. The inside of a diff housing is a oily, misty slurry being flung all around. Keep it from getting into your vent tube.
  • Run a long vent tube. Run it up straight up to the chassis (with room for droop) and then up as high as you can, even into the body, then loop it down back to itself to create an air trap and stick a small filter in the end of it. I like those little see-through plastic gas filters you put on garden equipment, but you could use those fancy vent cans like YJLOPES showed earlier.
    • You want it as vertical as possible, especially coming out of the housing, so any oil that gets into it, will drain back easily.
 
I've always just extended the breathers from the stock axle locations (Toyota 8" axles and later on 60/14B) using 3/8 hose and the stock
Toyota breather fittings. Never had a puking issue. My atlas and front 60 are vented up into the engine bay on the top side of the firewall on the Pass side and the rear 14B is vented up one of the upper links to about the mid line of my rear back half. I think its key to leave enough hose for potential expansion and and at enough angle where it can drain easily back to the axle housing.
 
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