Outer Limits 4x4 Board

i my 60 series winch truck it was setup so that when you engaged the aie locker it also pressuried the diffs to stop water getting in do you think i should redo it this way or just put diff breathers ?
cheers
nathan

tuff6ty wrote:i my 60 series winch truck it was setup so that when you engaged the aie locker it also pressuried the diffs to stop water getting in do you think i should redo it this way or just put diff breathers ?
cheers
nathan

surely 100psi would be pushing oil out of the seals? I'd just run decent breathers...

dogbreath_48 wrote:

tuff6ty wrote:i my 60 series winch truck it was setup so that when you engaged the aie locker it also pressuried the diffs to stop water getting in do you think i should redo it this way or just put diff breathers ?
cheers
nathan

surely 100psi would be pushing oil out of the seals? I'd just run decent breathers...

what he said

he never said anything about 100psi but i cant see anything wring with 2 or 3

youd still need some sort of diff breathers ideally, when they heat up the air needs to have somewhere to go.
If you pressurised them you'd need to keep the pressure low like the guys above suggested, you probably aren't going to drive through any more than 1.2 metres of water so if my calcs are correct the water would exert about 1.7psi on the seals (thats assuming that the water is 1200mm above the seals and isn't being forced into them) so yea any mor than 2-3psi may cause trouble.

If you're gonna set up 2-3psi plumb it to the gearbox, transfer and dizzy while you're at it, just don't blame me when you keep finding puddles of oil under the car....

Pretty sure military spec hummers had a similar set up, they could park fully submerged...

If it was my car tho i'd just extend all the breathers up high, not drive through water unless i have to, check all oils after water crosssing, you'll soon get to know which bits water gets into.
e.g. in my old MQ i drove through water over the bonnet a few times (wonnangatta at a high level) and got water in the front diff, and bottom of aircleaner cyclone but never anywheres else.

unimogs have pressurised diff, bellhousing, gearbox and headlights.
from memory the pressure is 2-3 psi. no problem with oil leaks and no problem with water inside any pressurised unit. they use a pressure reducer but again can't remember what brand. easier way is just to add extended breathers.

I would have thought the easy way would be to apply (say) 10lb and then use the breather to bleed off the excess pressure with a pressure relief set at 2lb.

Funny contrast. Here I am running my engine crank case at 5psi of Vacuum.

I wouldn't bother with the pressurising, it will be fairly difficult to regulate and should something get blocked you may have oil pouring out everywhere.

I suppose it depends on how often you submerge your car, and how long for each time. Most water crossing's i've been through have never been more than 10seconds or so.

If you intend to drive up a river... it may be a different story.