TaterN

No dice from search.
Does anyone know a safe water depth you can travel through without it reaching the stock breather?
I have yet to do the breather mod (extention). But I may be faced with having to do such a thing this week from the Ohio River backing up across part of a 900' driveway to my home. It's along a fenceline so I'll have a good idea of the depth.
BTW- I won't have the 4runner til tomorrow or I'd go measure it, if I can find it.
Thanks

rwmorrisonjr

It can reach about 18" deep. Good rule of thumb is don't go deeper than the center caps on the wheels.

Robinhood150

It's not that you absolutely can't go through deep water, it's just cheap insurance incase you do. If the stock breather is working like it's supposed to, then you should be fine. It's when there is junk preventing the cap from closing that is the problem.

INsr5runner

That, and if your gear oil is very hot, and you take a dip, the rapid cooling will cause the breather to open, thus allowing water in. and water will grenade your diffs.

toy283

Eh, my breathers don't operate that way. Just the opposite in fact. Rapid cooling of the gear oil and air in the differential causes contraction, sucking into the diff. The breather is designed to prevent this. It's sort of a check-valve, it allows pressure to excape, but closes under a vacuum. This is theory of course. One little grain of dirt can shoot that all to hell.

FWIW, with my current remote breather setup, I need to ford water deeper than 6'3" for water to get in. It'll get in the transfer cases (3'2") and engine (4'6") long before that. Higher is better.

Robinhood150

Yeah, it's the other way around...vacuum closes the valve.

INsr5runner

you guys are right sorry. maybe I should have reread what I posted...:pat: I guess it's time to

WATRD

Of course, there is another risk with the stock breather, whether it is in the stock position or raised.

When the stock breather is working properly, the axle develops a pretty strong vacum in it. When you immerse the axle, there is a vacum on one side of the axle seal and water pressure on the other That *can* cause a leak. Then there is the obvious, the breather getting a speck of dirt in it and failing to seal properly

toy283

That's why I won't use a stock breather on my wheeling rig. Mine is just vented to atmosphere to prevent both overpressurization and vacuum.

WATRD

I have a glass-bodied, rebuildable, fuel filter in the engine compartment for each of my breathers. That vacum was making me nervous.

Robinhood150

Me too.

TaterN

Thanks guys. As expected, far more info than needed, but just as well appreciated. I didn't realize there were many variations to the standard breather mod extention.