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Post by James W on Oct 13, 2005 10:22:40 GMT 11
I have been thinking for some time about putting compressed air into the front hubs to make them more robust when sumbmerged in water for some time. The idea being to use low pressure air to provide a slightly postive pressure in the hubs. At 1m water depth it is equivilent to 2PSI, so 3 or 4 PSI would be all that is required and not to blow out the oil seals.
This would extend into the gearbox and diffs as well, however they are easy with breathers already attached. The front hubs are a bit harder.
So I've been thinking about it for some time and while doing a wheel bearing this week I looked harder but my first idea didn't pan out when I had a look at the whole assembly.
I do want to put the air line into the stationary part to avoid rotating air joins.
I think one way is to drill a small (~1mm) hole in the stationary part of the hub between the upper ball joint and tie rod ball joint, into the hub and towards the small needle bearing... the problem is that aint easy.... and the needle bearing housing blocks any drilled hole.
So what I'm looking for here is someone who can help me on this project to bounce ideas off and gnerally work through the problem.
I have tooling and machine tools at my disposal so any project partners would benifit in machined parts and the final solution. Someone with a spare hub, housing etc would also be a help or prepared to loan one to me.
Anyone?
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Post by geeves on Oct 13, 2005 12:23:53 GMT 11
This has come up on the nz4wd forum but cant remember the outcome. I think concenceus was that it would cause as many issues as solve. Certainly with the diffs you end up blowing the oil out through the seals.
You could drill the hole at an angle to miss the needle bearing. I do have a stub axle assembly here that is past its prime but freight would be as much as buying one localy
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Post by James W on Oct 13, 2005 15:38:07 GMT 11
I think you missed one of my points geeves, that is I have no intention of blowing out oil seals, that would be too much pressure, in fact if I put in 2psi while submerged the pressure is equal. nothing happens, which is actually the goal. If you have ever had water in any of these places then the pressure was too low. So certainly if the pressure is uncontrolled you will have seal blowouts, but currently I have seal blowins!. I think you are right but also equally certain is that it can be controled.
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Post by geeves on Oct 13, 2005 16:05:14 GMT 11
Problem is the 2 - 4 psi while not in water or worse on top of a mountain. It wouldnt be hard though to have the air switched so its only on in water or even better figure out some way of automaticaly controlling the presure so its always 1psi hight thant whats outside the hub.
Ive just had to replace my second bearing in 6 months but the needle roller in the stub axle was nearly not there the seal had holes in it and the cv axle was quite rusty where the bearing is meant to run. The other side hasnt got a drop of water in in the 2 years since that got the same treatment
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Post by James W on Oct 13, 2005 16:34:50 GMT 11
Yes, all true, a regulator will do all this of course, usually a diaphram regulator works by comparing the air on both sides of a diaphram with a sping to bias it. That is it is relitive regulation to the atmospheric pressure or the same as outside of the hub. Apparently LPG gas regulators are about 2psi?
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Post by mulover on Oct 13, 2005 18:23:10 GMT 11
you could have a solunoid valve you flick on when you are getting near water, and i have 2 spare hub assembly's here if you wanna pay frieght. I haven't seen them yet to look at the condition, but if they are in good nick you can borrow one to play with, i am constantly getting water in my hubs but have now tightend up the seals so i'll see what happens.
Let me know if you are keen for the assembly, i have no idea of frieght, or get a hold of himuzulux, he might still have the ones off his mu.
John.
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Post by James W on Oct 14, 2005 4:53:42 GMT 11
Yes, a solenoid valve it was I was thinking, and thanks for the offer i may yet take you up on that, I've been meaning to try Steve (HiMuZuLux) also
I keep my seals all adjusted up, but still get water in everynow and then, it's not the 10 times that it's ok that you remeber it's the once the water gets in that is annoying.
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Post by mulover on Oct 14, 2005 18:57:30 GMT 11
Yeah, i know what you mean!!
I picked up the parts today and i got a real bargan, the aisin hubs are pretty much brand new, no water in the bearings, complete axles, brake calipers, and discs, plus top and bottom "A" arms, all for $280 delivered to invers from auckland!!
So let me know if you wanna borrow one, as they are only spares!!
John.
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Post by geeves on Oct 15, 2005 5:18:17 GMT 11
Had a look at the hub here and figured out how to do it without absolute drama. You need to drill 2 holes that intersect in the middle of the casting with the end of one blocked off. Drill the first hole almost parallel to the needle roller so it enters the inside of the hub after the bearing. Due to the shape of the hub this could end up quite some way down Maybe a third hole in the stub axle itself would help. Then drill a second hole at an angle to the first hole allowing a fitting on the outside and finishing in the first hole.
Apart from the black art of drilling long small diamiter holes it sounds easy and should work
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Post by James W on Oct 16, 2005 7:10:23 GMT 11
Thanks, all good thoughts, I now just need to get it done :-)
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