Moisture in Rear Axle

I recently pulled my rear axle to install a locker this weekend. When I got it torn down, I found rust. Rust on the inside tops of the tubes, and on the portion of the ring gear that wasn't in the oil while sitting. I changed the oil in the diff last year, prior to my Rubicon trip. The axle has no vent for water to get in, the oil level before tear down was normal(indicating no substantial amount of water entered the axle)so I'm kind of baffled how this happened.

How do I prevent the moisture build up? I was thinking maybe a vent with a hose plumbed higher up might help.

I'll post pics tomorrow, I didn't get a chance to snap pics today.

Any thoughts?

 

Heat, condensation , Moisture and no place to go = Rust..................Yes a vent is needed with a tube plumbed up higher............all the post 80 CJ's and beyond have that.

 

Thats what I think too, condensation

 

At least some Earlys had a elbow and vent cap on the pumpkin cover.

Fording cold water may suck water past seals as the inside air cools and contracts, without some kind of vacuum relief.

 

Yep.. Like the wet stuff inside a condom.. Condomsation.... hellokitty

 

Thanks for the replies. Here are a couple of pics after bathing in a hot tank for 3 days. I think it might be time to add some more powder to the tank .

The ring gear is pretty bad. Light rust and pitting on the face of the teeth about 2/3 around. I have little choice but to run it(-$). If I hadn't taken it apart, I'd be running it anyway:


Inside the tubes:


By the looks of this, the condition has existed long before I bought the Jeep. Maybe a PO allowed the axle to sit full of water at some point in history. Who knows. I am going to drill and tap a vent somewhere in the top of the housing before I reassemble this thing. Any suggestions as to where?

 

Clean it up best you can with a non abrasive wheel and let it Rip.........Like wise on the tubes get as much of that loose stuff out............ at this point any flakes of rust can't do much more damage except perhaps to the bearings but I think your fine!

 

Drill and tap the axle tube, close to the center chunk.. That's where a lot of factory vents are..

Bubba

 

Are you sure the axle is unvented? All had a vent when new and most or all the rears just had a hole drilled by the left spring pad on the rear face. It may be plugged. The stock vent hole is also prone to letting water into the axle if you submerge it long enough that it cools the housing.

I drilled/tapped for a 1/4 npt fitting in the top of the housing and ran a tube as high as I could get in the wheel well and put a sintered filter on a U fitting so it is facing down (to create an air trap). If you do this, drill/tap and plug the stock vent or just weld it shut. There should be some threads on the stock axle vent.

 

Duffer, bingo! This afternoon I found a hole maybe 1/8" partially plugged in the area you describe. I'm going to plug it and vent the top of the case.

I found a wire bottle brush 2" in diameter that I can drive with a drill to scrub the inner surfaces of the tubes. I will also scrub the rust off of the ring gear the best I can with some scotchbrite pads. Once done with that, the locker install commences!

Does anyone one have a part number for a repair sleeve for the pinion yoke? I found some pitting in the seal area there as well...

 

According to Rockauto the Timken p/n is KWK99155. Nation and SKF is p/n 99155. Prices range from $10.44 to $20.79 plus freight.

 

Do a search as either Howard Eisenhower or Walt Couch has posted pics of the small vent holes on the back of the housing countless times. There are usually two, one on each end on the back side if the housing, close by where the housing "bells out" for the axle bearing. This is for tapered axle civilian housings.


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