Diff Breathers

[FlyNdrive Advanced Member Find all posts View Profile Close FlyNdrive]

Most of us just run the rear breather up the rear of the vehicle, through to the rear storage and up near the tail lights.

There is no smell of diff fluid yet.

-Ben

[dustie Senior Member Find all posts View Profile Close dustie]

D4D30 & All,

You can source all your fittings from these guys:

www.purplepig.com.au

Hope this helps.

[FlyNdrive Advanced Member Find all posts View Profile Close FlyNdrive]

For the rear diff breathers I used valve cover filters from an auto parts store and added brass fitting to allow the clamps to be tightened without buckling closed the rubber fittings.



Here is the "T" Connector that we rigged. I was unable to find a 1/4 X 1/4 X 1/8 (like D4D30) so I went with a 1/4 X 3 and used a 1/2" to 1/8"a reducer of the locker hose several inches from the "T" connector.

used a 1/4 1/4 1/4 tee instead or a 1/4 1/4 1/8


I hope this helps.

-Ben

[dustie Senior Member Find all posts View Profile Close dustie]

Hi Guys,

In the 120 Petrol I find the similar to a "T" piece on top of the transfer case, this is also connected to the transmission. Yesterday I heard Toyo has done this because they found a pressure equalisation problem in 80 Series. Therefore I wouldn't combine the rear diff and transfer case breathers together via a T. I now have 4 seperate breathers, also the breather end I used the stock rather than use filters, one less thing to clean from all that dust.

Ben, did you join the rear diff and transfer case into a single line via the T or transmission and transfer case?

[FlyNdrive Advanced Member Find all posts View Profile Close FlyNdrive]

Ben, did you join the rear diff and transfer case into a single line via the T or transmission and transfer case?

Dustie,

I combined the rear diff & locker breather's to the "T" union (in the picture), and did the transmission & transfer case breathers on two separate extensions (Transmission 1/4" & transfer case 1/8")

-Ben

[dustie Senior Member Find all posts View Profile Close dustie]

Finally got around to completing. I found that the 1/8th hose can be completely removed from the top of the transfer case and replaced with a longer hose. This way you avoid the need for a coupling (less parts to come off). Pull the existing hose where shown.

You'll need about 3 - 3.5m of hose to be lifted into the engine bay.

Transmission & Transfer Case Breathers:

New 1/8" Hose and Coupling to run the breather up into the engine bay higher.


I reached down and slid this one on to the remaining hose. I again secured it with another tie wrap to keep it from coming off.

[LiveFreeAndRoam Avid PP Poster! Find all posts View Profile Close LiveFreeAndRoam]

Rear Diff Breather
'Cause we like pics so much, I have some of my install. For the most part they are the same as those before me, so I'll limit this to the rear diff breather which I threaded up the rear pillar.

One point... and not meaning to make light of the excellent workmanship and ingenuity of others... I don't see the need to add fancy air filters to the end of the breather hoses. I asked several other enthusiasts and they didn't see the need for that either. (FWIW, one of those enthusiasts was a Toyota Trail Teams member). So after removing the breather-valves and extending the hoses, I simply reattached the original valves. Saves a few bucks too :wink:.

Also, when running your tube from the rear-diff, be sure there is sufficient slack to allow for the travel of the suspension and still keeping the hose tucked up so it doesn't become a new low-point and get torn off on your next expedition. :idea:

Here are the four breathers:



I used one my daughter's many mirrors to get a better view of how to remove the rear breather. The other three were fitted into the hose, whereas the rear-diff was threaded directly onto the diff.



Lift the the corner of the carpet in the cargo area and feed the hose through the cargo-floor via the rubber-bung.



Remove the passenger side tail-light... I remember I did this so that I could easily thread the tube up the pillar, then access the hose via this space to reattach the breather valve.



Feed it up the pillar and out the tail-light space. I used a piece of wire to hook the tube and pull it out the tail-light. After doing that, reattach the breather-valve.



To be sure I don't get any rattle from the metal part of the breather tapping the inside of the pillar, I taped the metal parts of the breather... being careful not to tape the valve closed :!: Finally, push it back up the pillar, reattach the light and breathe easy

.

LFaR.

[FlyNdrive Advanced Member Find all posts View Profile Close FlyNdrive]

LFaR,

Nice write up. It's what should of been posted in the first place.

-Ben

[Violet Senior Member Find all posts View Profile Close Violet]

I don't see the need to add fancy air filters to the end of the breather hoses. I asked several other enthusiasts and they didn't see the need for that either.

OK I admit I'm not super experienced - and I'm very prepared to have other people disagree - but I think putting on the original valves is a bad move.

There are two ways that water can come in. One is via the breather if it sticks open - getting the valve above the water level will fix this.

However think about what happens when a hot diff (or gearbox etc) hits water. The air inside will cool quickly thereby creating lower pressure than the surroundings. If the breather valve is stuck open then air will rush into the diff - together with water if the valve is below the water level. However if the valve closes (ie working as designed) then air (and water) will (usually) get in via the spot of least resistance. Axle (or tail shaft) seals are designed to stop oil getting out - not air in. The likelihood of air (and water) passing is very high through these seals. If you allow air to get in via your extended breather then the likelihood of water getting in via other seals is VASTLY reduced.

So using this theory (and considering the ease of doing it), put some type of fitting on the end that will not prevent air passing along the breather but will not allow contamination with dust. Don't put a one way valve.

Does this explain things??

[MickL Addicted PP Member Find all posts View Profile Close MickL]

Great theory...just one thing... it's a breather, not a valve, :wink: ... it lets air pass in both directions (to equalize pressure whether diff is heating up or cooling)

The cap on it is only to keep large particles out.

Your description of water being drawn past the seals only holds true if the breather is blocked with crud/mud , which won't happen if it's up behind the tail light or in the engine bay.

Mick

[Violet Senior Member Find all posts View Profile Close Violet]

I think that they are a one way valve. Both that I removed from an almost brand new vehicle (a couple months old and had never been in muddy areas or through any water) would only pass air in one direction. I tried sucking through them and there was no way I could get any air through. I could if I blew through them. ie suck - no, blow - yes. This indicates one way valve. I tried this on both breather valves.

I suggest you try your own valves. Even if they can pass air through both ways now, they could probably be easily get jammed closed.

Again - it's very easy to put some type of filter on the end. This is much more reliable.

[MickL Addicted PP Member Find all posts View Profile Close MickL]

When you sucked it pulled the cap down and blocked it off, it was never designed to cope with that much flow!!!

Even if you dipped a hot axle in icey water you'd never get that much flow.

Whats the engineering thought process behind a valve?

Most gearbox/diff/drive applications (automotive and industrial) have breathers.

Mick

[dustie Senior Member Find all posts View Profile Close dustie]

Violet,
Going by your theory why would Toyota then put the front diff breather up in the engine bay :?: The breathers all look the same to me (x 4).

Doesn't make sense to me ... :? :?

[ronb1002 Lurker Find all posts View Profile Close ronb1002]

Just checked the "breather" I removed from the rear diff today. Definitely a one way valve - not a breather. Just about to replace the one on the front diff as well.

Ron

[Violet Senior Member Find all posts View Profile Close Violet]

My point here is it is very cheap to put in some type of filter,

Yes - perhaps my 'breathers' are faulty. Perhaps I was sucking too much (I did try several 'speeds' of sucking), perhaps they are blocked with crud... Perhaps, perhaps, perhaps.

Why take any risks? - just put on some type of filter, I agree if it was a couple hundred dollars - then I would reconsider. But for probably less than $15 - it seems very cheap insurance considering water in a diff/gearbox could cost hundreds.

As an aside - when I removed my factory fitted rear diff breather (I hadn't driven my car for probably 12 hours), there was a definite noise of air being sucked in to the diff. I had another person that saw/heard this and we both concluded that the breather was preventing air getting in. Yes this may also mean that my other seals were working well and they wouldn't let in any water - but perhaps when the seals were hotter or perhaps the pressure difference bigger or perhaps if the seals older,,,,
Point here is that they didn't let air through in my car. Perhaps all other Prados are different (mine is late 07 build)