jag ind rear breather problems

hi guys
on first long trip in model a we ran into a major problem with the diff blowing most of the oil out the breather pipe in the Mr Roadster jag quickchange cover.prior to leaving i had noticed it was doing ita little bit an moved the hose back to the rear most hole in the cover.both holes have baffles welded over them but obviously there is alot of oil movement inside that smooth cover an its getting under the baffles.
any ideas/help much appreciated.
mark
http://i290.photobucket.com/albums/l...k/DSC02720.jpg

you can see the original breather hole at the front
http://i290.photobucket.com/albums/l...k/DSC02718.jpg

http://i290.photobucket.com/albums/l...k/DSC02719.jpg

What's the routing on your hose?

when the problem is sorted it will go up an onto the fitting you can see threaded into the centre of the crossmember that holds the jag diff head. at the moment it is looped up over the square crossmember above the chrome spreader bar an cabletied to it with a rag cable tied over the end

I'm no expert on differential vents, but just looking at the placement and thinking about the dynamics it appears that the top of the cover where you have the vent fitting is going to be seeing a direct shot of gear lube slinging off of the ring gear as it spins. Comparing it to my 9" Ford, my vent is on the driver's side axle tube, about three or four inches out from the differential housing, and it's a simple lightly spring loaded cap with no tube at all, and it blows no oil. Can you move the vent out of the path of the oil sling?

My thought is its heating up the air is expanding and pushing it (the vapors) out the tubes ..Is there any way to have bigger tube so liquid can run back down with out being pushed out???

if you look at the 2nd picture ,the little green plug is where i originally had it and it is in approx the same position as the oriiginal jag cover, just a little higher. the original jag rear breathe was a plastic tube that came out of the cover just above the oil level an went up about 4" an had a plastic cap on a spring- i'll find a picture of one

My opinion is that you need to cover the top of your baffle completely, the bottom needs to have the smallest of openings so that pressure can escape but fluid is blocked and if any fluid does get into your baffle your opening will allow it to drain.

Seems to me that the little green plug would be a better location, out of the direct sling path off of the ring gear, but I could be all wet.

Certainly not an expert on differential vents here either bit is seems to me that getting the vent high with a long hose may help this problem. Speedway has a kit - New Longacre 1 1 2" Clamp on Billet Rear End Breather Vent Kit w Hose | eBay but you could duplicate this with a nice stainless hose and a billet vent cap mounted as high as possible allowing the oil vapor to escape the rear end but cool and return as well.

the problem i've got is there is not much room under there to gain height and up into the mudguards isn't an option.the green plug is where i first started off with the breather and i'm thinking of playing around with the baffle there and going back to that spot as roger says-it seem to be the most logical spot.another thing is with the extra space in the quicke cover-theres an awful lot of oil in there compared to standard-wonder if i can run less??

You have to maintain lube [U]level[U] Don't use less and risk bearing failure

I agree 100% with Charlie, your fluid quantity is spec'd to give a specific coverage of bearings and you don't want to run lower. Just thinking, what if you came off of that green plug with a thread to compression fitting and took a three or four feet of 1/4"/6mm copper tube coiled in a tight spiral maybe 3" to 4" diameter ending with the tube coming back to center and turning up. Another tube fitting with a cap that has a nominal 1/16" or 3/32" hole drilled in the center? (fitting, tube bent straight up and coiled ending pointing up w/fitting - each turn on a 4" circle will eat a foot of tube) If it works you could replicate the whole thing in highly polished stainless to match the other bling, or just polish the copper & brass and clear coat it! By pointing up the coil would be self draining back into the diff, and there would have to be enough pressure to push oil up through the whole tube to get out. It would add an interesting "look" if done neatly. Just a thought....

Sandwitch a stock Jag cover between the rear housing and this quick change look a like piece---you can probably then just use the space in this Bling as a breather and leave the top with a tiny hole by drilling holes thru the Jag cover at bottom (for drainback) and in some other places for ventability--------

Quote:

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Originally Posted by jerry clayton

Sandwitch a stock Jag cover between the rear housing and this quick change look a like piece---you can probably then just use the space in this Bling as a breather and leave the top with a tiny hole by drilling holes thru the Jag cover at bottom (for drainback) and in some other places for ventability--------

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I'd be afraid that I'd never really know where my lube level was running, as the space between the two covers would tend to fill with gear lube. Any hole at the bottom of the stock cover would cause the fluid to seek a common (low) level in both covers over time, not drain back into the main housing. I don't see two covers being the answer, and think it would be a second leak source. Just my $0.02.

Roger ( and others)


The whole porpuse of a breather is to somehow separate oil out of an oily vapor mix and return the oil liquid to the sourse while venting the vapor PRESSURE to the atmosphere--it is also necessary to somehow relieve an negative pressure in between these positive moments---


Now---with a plate (stock cover) between the housing and the Bing, it is only necessary to put a drainback (hole at bottom) and some other holes somewhere up above the liquid level and out of direct sling off area of the fluid--that will creat the separator and it only has to be vented to atmosphere by what could be a single hole as small as 1/16 to 1/8 inch---


And the fluid level will maintain itself at the filled level minus only the small portion that will be separated in the breather (volumne of cover to bling

I just wrote a lengthy post explaining this from the very simplist basic views to the upward levels of a nascar/F1 version of fluid/vapor controls and it wouldn't post-----so much for me on this post

Quote:

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Originally Posted by jerry clayton

Roger ( and others)
The whole porpuse of a breather is to somehow separate oil out of an oily vapor mix and return the oil liquid to the sourse while venting the vapor PRESSURE to the atmosphere--it is also necessary to somehow relieve an negative pressure in between these positive moments---
Now---with a plate (stock cover) between the housing and the Bing, it is only necessary to put a drainback (hole at bottom) and some other holes somewhere up above the liquid level and out of direct sling off area of the fluid--that will creat the separator and it only has to be vented to atmosphere by what could be a single hole as small as 1/16 to 1/8 inch---
And the fluid level will maintain itself at the filled level minus only the small portion that will be separated in the breather (volumne of cover to bling

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Jerry, I mis-understood what you were saying about the way the two covers would work, and it seemed to me that you were suggesting that the void between the two would remain empty, there only for a vent area. Obviously that's not what you meant.

I would suggest that if you used both covers you would want several large holes at the bottom, or even a significant portion of the stock cover cut away so that the lube level would equalize quickly during fill. A small hole at the top, and equally a small vent in the "quick change" cover would handle the venting both ways, out and in. The only concern would be getting the outside flange of the stock cover smooth and flat to seal to the "quick change" cover.

But I think I'd try the vertical coil of tubing first......

Roger--the only problem with usinf a coil of small diameter tubing is that the smaller the tubing, the further it squirts----needs to be larger to allow liquid and bubbles to separate and drain back because of gravity--


Problem with the set up as Sharpmark has it is that the sling off from gear will constantly be going in that direction and going out---
With the OEM rears where it is on top over the axle tube---that is a high vlume area of probably 3 " tube for separation and drain back with small hole to relieve pressure adequately to prevent blowing past the axle seals---------


On hotrods, people really need to copy what the oem manufacturers have done--if it works on millions of daily driver/work vehicles, it will probably work on a trailer queem

Yeah, that's a good point on the tube size, and bigger than 1/4" would be better. On the sling, that's why I suggested using the other hole, currently identified by the green headed bolt. I'd probably start with the 1/4" in the OEM location, and if it didn't work boost it to 3/8" or so. Away from the sling forces the little tube just might work, and a few feet of copper tube isn't that expensive!

Many off road racers and others who work their off road trucks use "catch cans" on their diff and transfer case breathers. They are actually small expansion cans very similar to the ones used on radiators, with a fitting inlet connected to a tube that reaches to within a fraction of an inch of the bottom of the can, and a filtered vent fitting on the top of the can. Any oil that gets caught in the can and reaches above the level of the bottom of the tube gets pulled back into the diff as the cooling draws air back in through the filtered vent. However, in your situation, one or another of the fixes already put forth should work quite nicely; my suggestion is just another bit of fodder to toss in the idea mixer.

thanks for all the replys.i did consider the original rear cover sandwich but i would'ht have put any holes in it -- just left the original breather on it and left one of the plugs out of the quickie to let the air out.on an original jag i drove there was never any oil coming out of the original breather.the problem is i don't have an original cover only photos!!!i'm going to change the shape of the baffle over the front breather and increase the diameter of the breather hose and put some anti-foaming in and see what happens.
next option will be the coil idea.
once again thanks everyone for the interest in my problem- i'll keep you all informed.

problem solved-thanks for all the input.
what i did was plug the rear breather hole and weld completely round the baffleplate closest to the diffhead and then drill 2 small holes in it top and bottom.
i also drilled and tapped the breather hole to 1/2"bsp and used a larger diameter hose.i used a length of hose with a horizontal loop in it and cabletied it to the pickup floor crossmember temporarily.
went on a 400mile trip an not a drop of oil came out so will now replace the temp hose with a blingy piece.
once again thanks everyone.

So that's why I never saw you or the truck after Friday!
You went home!