Pressure in Diffs

[timmay556]

Heres a thought for the people with hands on knowledge...

With diffs I hear people run diff breathers up to their engine bay all the time but I'm a simple lad and would prefer to just pressurize my diff then #### around with all that.

SO

Is there a 1/8 bsb ( I think it is - Hilux Diff) that has like a nossle on the end that you can attach to say a bike or car wheel pump and put say 2-4 psi in the diff so that when you drive into cold water it doesn't take a gulp of air rather the air inside just thins out?

I will leave that thought with you.

[Mud Hog]

Heres a thought for the people with hands on knowledge...

With diffs I hear people run diff breathers up to their engine bay all the time but I'm a simple lad and would prefer to just pressurize my diff then #### around with all that.

SO

Is there a 1/8 bsb ( I think it is - Hilux Diff) that has like a nossle on the end that you can attach to say a bike or car wheel pump and put say 2-4 psi in the diff so that when you drive into cold water it doesn't take a gulp of air rather the air inside just thins out?

I will leave that thought with you.

Do a search there was a big thread on this a while ago.

[monstr]

I would have thought you would get the same result as having blocked breathers ,the axle seals will be more prone to leak,

[rokhound]

Pressurise diffs, trans etc with a high volume, low pressure pump. (airbed pump is ideal).

[NJV6]

Yes, you want either very low pressure or drill and tap a new fitting as otherwise you just (blow) let oil out!

[niblik]

take out ya std breather silver thingy thats on top of ya diff and screw in an air fitting. then i've done what cokhound's said and got it on a manual switch for when goin through water..

works a treat..

[pruggerdore]

I think he means just put 2-4 psi in a diff and leave it there.

Dont think diff sels are good enough for that. air is thinner than oil.

Im planning to do the air bed pump thing, so all breather pipes to a manifold with the pump on that. what I want clarifying is do you completely seal up the system and the presure builds up against the pump. the pump can handle that??? and the presure dosnt keep rising and put to much pressure on seals etc??? just not sure if people are bleeding off some of the air too keep presure down.

[niblik]

ah... click..

doesnt sound like a viable option. for the work of 'air tight'ing the diff and fillin with air (when it heats up during operation it'd be different again too), i'd just run a simple breather line..

option two was the pump.

i have my on a selectable switch... then its not running constantly as theyre only cheap pumps and not really made with longevity in mind..

if you test one of the bed pumps (style and type dependant) it chucks about 3 - 4 psi.. spot on.. it'll just back up and start to whine more. sorta like rex. i dont like that though hence the direction i went..

[wjw]

In the prado I had an airbed pump into 1" heater hose, that reduced down to standard size breather hose into the diffs, gearbox, dizzy etc. Never got water in them. I ended up using garden irrigation fittings for everything.

You can't really just put air in and leave it there...

[haynzy]

just pipe it out and up to to the passengers seat then when you get to your water crossings the passenger pumps like mad till the other side

[timmay556]

ah makes sence after all.
I like the idea of pipeing it to the passengers seat

[meatc]

You shouln't need to pressurise the diffs etc. As they heat up with use the air inside expands takes up meore room and needs to escape, hence the breather, seal the breather and the air will go out somewhere else, like the seals.

Plunge hot diff into cold river and it suddenly cools and needs to suck air in to replace the space left by the cooling air, hence the breather again.

The original post was about leaving pressure in the diffs to avoid piping, this won't work.

Simpliest fix is unscrew the 1/8th npt fitting out of the diff put in a brass 1/4" hose tail and use a bit of tube up to the top of the fire wall or inside a rear gaurd etc, if you are fussy stick a fuel filter on the end to stop the mason bees.

[darinz]

Fit a good breather and you don't need to muck around with anything else. I've never had water in diffs apart from when the fitting got broken off my front diff.