So explain how the cold water completely skips cooling the diff and goes instantly to cooling the fluid? The giant cast iron housing is going to act like a giant insulator to the fluid. Y'all are talking about super cooling the fluid instantly. Ain't gonna happen.
Can't Breath with the Breather Mod?
- Thread starter cp99sr5
- Start date
So explain how the cold water completely skips cooling the diff and goes instantly to cooling the fluid? The giant cast iron housing is going to act like a giant insulator to the fluid. Y'all are talking about super cooling the fluid instantly. Ain't gonna happen.
KidVermicious
New member
Not sure who you're arguing with, but I didn't say instant. Metal is a great temperature conductor and a flowing river of cool water is an effectively infinite heat sink. Sit a hot axle housing and differential in that water for very long and you will see rapid temp loss. The air and gear oil inside the housing will cool. As they cool that can cause enough vacuum to suck water past the axle seals, IF they're weakened by age or compromised by a couple years of air and gear oil going the other way every time the diff heated up.
I've never had water in my gear oil. I've seen it on three other trucks, and each of them had leaky axle seals and a clogged breather and sat in the water for a couple minutes.
Leaky axle seals and sat in the water for a couple of minutes. Exactly. The seals were compromised before ever hitting the water. Not because the fluid cooled and produced a vacuum to suck the water in.
This is a simple breather folks to let air expansion and contraction happen. Don't over complicate it. Extend the tube up and be done with it.
This is a simple breather folks to let air expansion and contraction happen. Don't over complicate it. Extend the tube up and be done with it.
Hesk11dog
New member
My rear diff breather is severly rusted and i dont think it functions anymore. I dont wheel, just drive gaswell roads and the usual hunting and fishing roads. In your opinion, should i just use a factory replacement breather or go ahead with the mod? I plan on doing the fluid change next week and wanted to get this fixed while i am doing that.
KidVermicious
New member
Thanks for agreeing with me. Next time just skip to this part, would you?
Try a small engine shop.
Myrunr2010
New member
It is two different things to say that the fluid/air expands/contracts and the fluid/air expands/contracts fast enough to cause a vacuum that breaks your axle seal when running your rig through arctic rivers and super cooling it.
Myrunr2010
New member
Correct. And I used proven and accepted engineering formulas to prove this in lieu of just theorizing.
2014 Warthog
New member
Not sure what this is supposed to mean...
You extend it to keep it above the water (The front diffs come that way from the factory)
And you put a filter on the tube to keep dust from offroading from getting into it and possibly clogging it or reaching the diff.
A HUGE amount of dust gathers in my gas cap area. I ran my tube up to the top of the firewall. There is evidence of a very large amount of air travel through the filter. I would not want to leave it open if the tube is anywhere outside the cabin of the vehicle.
Some people run the tube up inside the cab and at that point a filter may not be necessary. But anywhere else, yes, there should be something covering the end of the tube to keep dust out.
The non filtered and low level Toyota valve is "fine" because 99% of people only drive on the street. This mod is for people that actually offroad and occasionally need to ford rivers or large puddles. In that case it has been shown that the standard valve is not fine...
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KidVermicious
New member
This is the part where you start saying stupider and stupider things until I get frustrated and walk away, right? Lemme save you some time.
cp99sr5
New member
I am not sure either if metal contraction is the issue. I think its the expension and contraction of the air inside the housing but I am not an engineer so I cannot calc the force of Vac created by cooling a volume of air (a pint. quart or even gallons worth) 20 degrees F and if the force that is created by doing this is strong enough to pull water through the seals given that the breather cap will close when this happens. I was trying to determine the mods effectiveness when I posted my thoughts.
In thinking about the purpose, the vent cap is to allow the release of pressure and if the diff were to hit water and cool, prevent water from flowing into the diff by having the cap seal quickly. IMHO it was an issue of economics for the engineer, we need the diff to vent so how much do we want to spend on a bullet proof breather system versus a very simple design that works to solve the problem which is preventing water from being sucked into the diff from the breather valve, and not worry about the vac being strong enough the suck water through other areas. Now that might be the real myth here that sucking water through the seals is even possible? I think the mod is probably effective in that it removes the possibility of of having water surround the cap and being sucked in at all. I love mods, but if I am going to spend money and time to do them, want to get the most bang for the buck!
In thinking about the purpose, the vent cap is to allow the release of pressure and if the diff were to hit water and cool, prevent water from flowing into the diff by having the cap seal quickly. IMHO it was an issue of economics for the engineer, we need the diff to vent so how much do we want to spend on a bullet proof breather system versus a very simple design that works to solve the problem which is preventing water from being sucked into the diff from the breather valve, and not worry about the vac being strong enough the suck water through other areas. Now that might be the real myth here that sucking water through the seals is even possible? I think the mod is probably effective in that it removes the possibility of of having water surround the cap and being sucked in at all. I love mods, but if I am going to spend money and time to do them, want to get the most bang for the buck!
bugman-74
New member
For clarity: 90930-03136 is not a valve - it is nothing more than a splash shield. It is simply a crimped metal cap on top of a plastic barbed tube. See posts below for description of a second type of Toyota breather that is a 1-way valve.
Note that for 90930-03136 even when the cap is fully against the shoulder, air still flows both ways thru the breather. It does this via the crimps in the cap. This breather P/N will prevent both positive pressure and negative pressure (vacuum) situations (and can be used with a length of hose and threaded union fitting #90404-51319). They are not, however, waterproof.
The 90930-03136 Toyota breather, when placed up high, is more than sufficient for many of us. The ARB system is neat, however it is nothing more than a sintered bronze filter. These can be had from SMC (or ebay/amazon) for <$10 (look for sintered exhaust, breather, etc.). Beware that these can clog easily, and it is not visibly apparent that they are clogged - they are also more susceptible to water infiltration in comparison to the Toyota breather.
Note that for 90930-03136 even when the cap is fully against the shoulder, air still flows both ways thru the breather. It does this via the crimps in the cap. This breather P/N will prevent both positive pressure and negative pressure (vacuum) situations (and can be used with a length of hose and threaded union fitting #90404-51319). They are not, however, waterproof.
The 90930-03136 Toyota breather, when placed up high, is more than sufficient for many of us. The ARB system is neat, however it is nothing more than a sintered bronze filter. These can be had from SMC (or ebay/amazon) for <$10 (look for sintered exhaust, breather, etc.). Beware that these can clog easily, and it is not visibly apparent that they are clogged - they are also more susceptible to water infiltration in comparison to the Toyota breather.
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cp99sr5
New member
Bugman, good to know - "Even when the cap is fully against the shoulder, air still flows both ways thru the breather." I bought my kit from Yotashop and it came with a "Splash Shield" unfortunately, when I tried to suck air through it, it locked down as stated in my OP and I could not get any air through the tube. I will try that with the Toyota splash shield and if it allows air in the reverse direction then I will swap it out and be done!
pluton
Senior Member
To the contrary.....
Toyota has made both kinds: the one-way, and the two-way. They are both Toyota parts.
The one way is threaded and screws into the diff.
The two way has a simple hose barb, and is intended to be placed at the end of a hose.
I don't have the part number for the two-way one in front of me, but right now I've got both types in my spare parts box.
The one that came on my '97 3rd gen, as well as the ones that came on my 4WD '91 truck, and two Land Cruiser FJ 60's, were the one way type.
Additionally, the one way is all metal(except for the rubber flap inside), while the two-way has a plastic body with a metal cap.
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Myrunr2010
New member
That's what I thought you were going to do? I think we have our roles confused. You were supposed to tell the story about grandma's old ford I thought?
cp99sr5
New member
Final thoughts, hopefully!
1. The valve that came off the axel and the valve that Yotashop sent me in the kit are one way, both have threads, either that or I got COPD and lungs arent working right.
2. The fatigue of seals from age and damage is potentially a larger contributing factor to water damage and can be exacerbated by a dirty/faulty valve.
3. Moving the valve out of the way of potential damage and dirt is a worthwhile mod because a properly functioning breather helps eliminate possible damage to seals.
It would be priceless to be able to spend some time with the engineering team that put this vehicle together and do a walkabout of the 4Runner!
1. The valve that came off the axel and the valve that Yotashop sent me in the kit are one way, both have threads, either that or I got COPD and lungs arent working right.
2. The fatigue of seals from age and damage is potentially a larger contributing factor to water damage and can be exacerbated by a dirty/faulty valve.
3. Moving the valve out of the way of potential damage and dirt is a worthwhile mod because a properly functioning breather helps eliminate possible damage to seals.
It would be priceless to be able to spend some time with the engineering team that put this vehicle together and do a walkabout of the 4Runner!
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bugman-74
New member
Interesting! I stand corrected, post updated.
I was under the impression they were both the same. The P/N I was describing (and have taken apart) is 90930-03136.
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Konkordmusk
New member
Those formulas generally work better when you use accurate numbers as opposed to numbers that "seem like they would work."
Also, your formula post calculates for steel, but not for cast iron like you just mentioned the axle housing was made of. Just my observation.
Either way, the issue is certainly not due to the metal expanding by itself, but rather the internal pressure/vacuum created by the addition of gas and fluid. Think psi and hg.
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Myrunr2010
New member
Yeah, I didn't go out and measure the axle to get accurate measurements, and I used an equation for length in lieu of volume, which would likely give a more accurate result. And correct, I used the coefficient for steel. Using the coefficient for cast iron should net an even smaller change.
