Rear diff breather question

[Falkon]

I just extended my rear diff breather to the rear light compartment. I had read that since it is moved away from water, you do not want the extended breather to seal with negative pressure because it could cause water to be sucked in at the axle seals, thus nullifying the reason for the mod in the first place.

I used an oiled cotton filter that will allow heated fumes to escape, but will also allow air back into the diff in the instance of a hot pumpkin hitting a cold stream. Whereas the stock breather would close and seal out water and air I would suppose.

So now I am wondering if I made a mistake using a filter that will allow air in? Is it an issue for air to flow into the diff? It would seem that any time there is negative pressure in the diff with the stock breather, it would seal air out.

- Chris

 

[mtnbike28]

More info....

I am following with interest. Just for background, I ran my breather up to the gas filler and have no filter, it's just an open hose. No problem in 70,000 miles.... But I have always wondered.... I have dumped my rear axle in an ice filled river several times and had no problems.

 

[Falkon]

Thanks mtn, good to know!

 

[Triumphdog]

Pics of the dif breather please. I'm intersted in doing the same. Thanks

 

[keezer37]

4307's Breather

Drill down about half way thru the pics in post #124.

 

[Falkon]

Since you asked.

 

[TEJASYOTA]

I just reused the one I removed from the rear diff... mine is routed at the gas filler area.

 

[Triumphdog]

thanks guys!!

 

[TangoBlue]

I just reused the one I removed from the rear diff... mine is routed at the gas filler area.

Same for me. It's been working on Toyota axles since the FJ40 was introduced... if it ain't broke...

 

[Falkon]

Did y'all just drill a hole into the gas filler compartment to get the tubing in there? I am rethinking my location, the rear light compartment looks like it gets a good amount of dust and dirt in it and I could see the filter getting clogged.

 

[mtnbike28]

Yes, drilled the hole, ran the hose through and then used a hose clamp to keep it from sliding back through

 

[Deleted member 13060]

So now I am wondering if I made a mistake using a filter that will allow air in? Is it an issue for air to flow into the diff? It would seem that any time there is negative pressure in the diff with the stock breather, it would seal air out.

- Chris

As the diff heats and cools air will be drawn in and out the breather due to expansion and contraction. As long as the filter isn't clogged it will be the path of least resistance and nothing but filtered air will get to the diff. The ONLY way you will pull water past the axle seals is if that some how becomes the easiest path......

YMMV RON

 

[01tundra]

I used an in-line fuel filter that I picked up at Autozone, in conjunction with a Summit Racing billet breather cap. Mounted it right above the fuel filler area behind the fender.

 

[Owyhee H]

I just reused the one I removed from the rear diff... mine is routed at the gas filler area.

I would not use the stock breather because it does not function in a way that is very beneficial moving it up. The theory behind raised breathers is that when going through a crossing the air inside the axle housing contracts pulling water in. The stock breather is meant to be a one way valve letting excess pressure out but not allowing water to be sucked in. Because the stock breather is a one way valve it seals and the water is pulled in through the axle seals. Moving up the stock breather does not change this problem, it will still seal causing water to be sucked in through the axle seals. The most effective raised breather is a two way end that allows the expansion and contraction of the air in the axle housing without sucking water in. You may never have the problem but to get the most benefit of the raised breathers you should use a two way breather end, filtered or not. The new tacomas have raised front diff and transmission breathers that use the two way breather end. The rear is the same old one way valve that has been used for years, located on top of the housing. To get the most benefit and still use Toyota parts you can use the breather from the front Diff and tranny in the rear, moved to higher on the vehicle. My Rear breather is routed to the cubby hole on the inside of the bed, with the two way breather.

I hope to never be in water so deep I need to worry about my breathers or intake, but chance favors the prepared.

 

[Falkon]

Ron, I guess if the seals were getting weak, that could be the proverbial straw.

Speaking of which, I noticed my fronts are leaking...

01, your design is top notch. I'd expect no less after the Tundra. I dig it.:thumbup: I am already planning a redesign to my breather set up. Have you had any issues with the fuel line rubbing/chafing?