pressurising diffs and gearbox

[zookfest]

ive got a 12v valeo compressor and have all the bits to plumb it into my breather system i have air gauge for the dash but what i need to know is how much pressure i should run so that i dont damage seals ect and how i can regulate it

[Sadam_Husain]

Never done it but I'd doubt you'd want more than a few pounds in there

[zookfest]

yea my thoughts exactly

[rangimotors]

i might be able to give you an adjustable regulator from an old machine at work, ill see what i can dig up.

[zookfest]

wikid dave that could be perfect

[rangimotors]

wikid dave that could be perfect

do ya a deal with one of those 33's you have

[albundy]

I set up one of those cheap airbed pumps under the dash, flick of a switch it is pumping 2-3 psi into diffs, gearbox, and tranny when wading through deep water. Have been running for 4 months now and no water in oilsd. used to always fill up before this mod. Only complaint is its loud when operating.
Al

[rangimotors]

One of these would do the job..


But i have some of these as well, with a water trap, gauge, regulator and that thing on the left is a 24volt valve so we can hook it to a switch to turn it on and off if ya want?

[zookfest]

sweet as dave keen as on the second one with 24volt as the truck is 24

[rangimotors]

sweet as dave keen as on the second one with 24volt as the truck is 24

cool, should i just bring it to the pub on thursday?

[zookfest]

yea mate what do you want for it

[rangimotors]

talk to ya on thursday about it

[rokhound]

You need to have a max pressure of 4-6 psi. Most standard oil seals go to 7-8 psi.
If you are regulating compressed air, you will need a fairly specialised reg to run at that lower pressure.
I have the same set up as Albundy is talking about, (been running it for 6 years or more) and it works a treat. These cheapo air bed pumps have good volume at very low pressure.

[H2OLOVA]

The hassle with using a standard compressor is they wont supply the volume of air you need to fill both diffs, g/box and transfer case without having to run a higher pressure. Thats why you should go with a high volume airbed pump. Supplies lots of air without the pressure. I've got this setup in my truck and works a treat, but like Al mentioned it sounds like i've got a vacuum cleaner in the truck when its running.

[fweddy]

I'm sick of draining water from my diffs too and am looking at doing the same.

Is there a special type of airbed pump that is best? does it need regulating or a release valve? Do you run a meter to see what pressure you are running or to make sure it is up to pressure?

A quick sketch with all parts marked and perhaps a pic or two would be awesome!

[rokhound]

No special gear required. Run all your breather tubes to a common manifold , and then have the air bed pump supply the air to the manifold. Don't restrict where the pump draws the air from or the volume suffers. Also make sure that the pump is drawing air from somewhere that is dry! (you don't want to be pumping your diffs etc full of water and shit )

[albundy]

Mount under your dash with wiring to switch on dash. Run one piece of tubing from pump through firewall to engine bay. I was lucky as all my breathers come back to one central point in engine bay. I just ran the tubing to that. I ran the pump and disconnected the breathers at the gearbox, diff etc to ensure there was air getting through, it was. No pics as all hidden except for switch. All you need is the pump $20 from supercheap, some tubing (got some suction tubing from work) and about a dozen beers, frist 6 to think the idea, last 6 to fit it up.
Al

[rangimotors]

this is vry true dean, as much as we can regulate the pressure to what ever you want it will drascially limit airflow and you will end up having to turn it on 5-10mins before you go swimming to give them time to pressurize.

An air bed pump sounds like to go, i like the idea of running it all via a manifold or catch can arrangement, so that the input of air goes in the top and all the outputs to diffs etc also come out the top, anything else can be drained out the bottom, so long as you stay shinny side up .

[KiwiBacon]

The deepest you're ever going to be is about 1.5 metres.
1.5m gives a static pressure of 2.1 psi.

Any more is just going to blow oil back out the seals.

[vvega]

you wont blow anythign out the seals are designed to grip the shaft harder with more pressure
you will however increase shaft wear

[H2OLOVA]

you wont blow anythign out the seals are designed to grip the shaft harder with more pressure
you will however increase shaft wear

But only for the 2 minutes your in the water with it turned on

[albundy]

But only for the 2 minutes your in the water with it turned on

Mostly, can remember a trip you pulled two trucks out of the upper grey Jas, yet to test the system under that sort of time in deep water only a matter of time I suppose

[KiwiBacon]

you wont blow anythign out the seals are designed to grip the shaft harder with more pressure
you will however increase shaft wear

Go put 10psi into your diff and gearbox breathers. Take photos of the ground before and after.

Any extra pressure will push the seal lip onto a slightly different part of the shaft. Unless that part is completely clean, ungrooved and free of corrosion then it'll start leaking.
Show me a 4wd shaft which is clean, ungrooved and corrosion free.

[vvega]

you wont blow anythign out the seals are designed to grip the shaft harder with more pressure
you will however increase shaft wear

Go put 10psi into your diff and gearbox breathers. Take photos of the ground before and after.

Any extra pressure will push the seal lip onto a slightly different part of the shaft. Unless that part is completely clean, ungrooved and free of corrosion then it'll start leaking.
Show me a 4wd shaft which is clean, ungrooved and corrosion free.

i have a pile of spares that arnt .....
i spent 5 years in hydraulics rebuiling pumps,motors,rams and repairing broken shit so i saw it everyday
i know for a fact your wrong
your talking .5 or less of movement with 10 psi and disputably it probably wont even shift at all if the you have factory steel backed seals 10 psi ant #### all
if the seal and shaft are in good condition it wont leak if your seal or shaft are damaged then .. its not the pressure making your shit leak its the fact its fucked

oh and my diffs and shit wont leaks ... why because ive just rebuilt them and the surfaces are like new and the seals are brand spanky
perhaps you should be doing more maintance on your own gear if this is a issue for you

[coxsy]

pity its a pain to pull my rear axles other wise i would show you

[fweddy]

All you need is the pump $20 from supercheap,

Guess one of these will do the job?

http://www.trademe.co.nz/Sports/Camping-outdoors/Other/auction-210356582.htm
http://www.trademe.co.nz/Sports/Camping-outdoors/Stretchers-mattresses/Air-beds-pumps/auction-209707664.htm

[vvega]

thats a sweet little unit
might get one for my engine cam cover

[Windsock]

you wont blow anythign out the seals are designed to grip the shaft harder with more pressure
you will however increase shaft wear

If indeed the rubber seals were "forced" to seal against a spinning shaft by pressure, I'd have thought the rubber seal would show wear from this first before any wear on the shaft. This would, over time, then lead to even more oil leaking out once the system returned to atmospheric pressure. Wouldn't it?

If seals are in such a state that water is leaking into diffs and gearboxes, doesn't seal replacement make more sense than pressurising? Also, if water leaking in is a problem, then this to me would indicate that any increased pressure above the pressure induced by depth (while wading) would lead to a small amount of oil being pressured out. Note I said small amount, not talking about pouring out. Yeah I know about the differences in viscosites between the two fluids.

[haynzy]

you wont blow anythign out the seals are designed to grip the shaft harder with more pressure
you will however increase shaft wear

Go put 10psi into your diff and gearbox breathers. Take photos of the ground before and after.

Any extra pressure will push the seal lip onto a slightly different part of the shaft. Unless that part is completely clean, ungrooved and free of corrosion then it'll start leaking.
Show me a 4wd shaft which is clean, ungrooved and corrosion free.

again you are talkin out the hole at the southern end of your body,This method is tryed and tested, although not 10psi only about 4 but it does work, doesnt leak and keeps water out.
my bit said
Hopefully mr bacon you are not one of these finger tapping 4wd owners that owns one to get to work and nothing more as you seem to lack the practical knowlege that you get in the mud rather than in a university lecture.

On a positive note, I am about to do a similar thing but with a live bait tank off a boat. 12v and low pressure

[vvega]

weeeeelllll
yes they do wear.. but they basically they polish the shaft to put it simply but i did mention increased wear by adding pressure

you can get dynamic seal with a wiper on the outside ,, its helps a lot with keeping the shitout (leading cause of adrasive wear)
but basically yes 100% if there fucked fix them

basically as has been said
it works ... so there is sound reasoning behind what there saying