'73 Axle seal leaking

[opelenvy]

The bearing is tight, this is the second new axle seal in a year, and after a couple hundred miles there is a bead of gear oil out the axle housing, down the tire and just a spot on the floor. I called Gil and he's not sure what to think either. But then I got to thinking about the vent tube on top of the passenger side axle housing. I don't have any idea how any pressure builds up in there. I think I read something about "misting"? Well there is obviously a vent there for a reason. So, if the vent is plugged, would it cause pressure to be release somewhere else? For example the axle seal or the diff gasket? It is also damp around my diff gasket, which I just figured was ok, since it's not even enough to drip.
I took the cap off the vent tube and took my smalled allen wrench and stuck it in there. It went the length of the tube and then just hit metal. How big is the vent hole and where is it? I've thought about taking off the fill plug and shooting some compressed air in there.
Any help from someone who has had the rear end out and looked at the vent up close and personal?
Thanks,

[namba209 (R.I.P.)]

George, I did the same thing you did, I dropped an allen wrench down the hole after I took off the cap. It hit the axle about 1.5" below the top of the vent. This was done on Willit? which has not been on the road since a rear-end rebuild with a ZF posi. HTH.

[opelenvy]

It hit the axle about 1.5" below the top of the vent.

Hmmm. So is the hole the full size of the vent tube? I am only getting the length of the tube before I hit solid. I know it is no where deep enough to be hitting the axle. Hmmmm. I scraped the allen around and it was solid metal. I was looking for a hole through, with no luck.
I'll try some more. Thanks Ron.

[opeldean]

with out axle its a straight shot thru, here is a junk axle that I cut the vent off, vent is a hole with a wire in it- 70 axle is shown

[namba209 (R.I.P.)]

George, I guess I should have read your first thread a bit closer, you asked for the ID of the vent, so I went back out to Willit? with a bunch of drill bits and dropped them in the hole. They all went down the same, right at 1.5", but to answer your query, a .208/9" drill was snug all the way down the same 1.5". So I'm presuming there is nothing between the axle housing and the axle at that point. Your idea of putting compressed air in the filler is not a bad idea, but I would limit the pressure to about 5 psi or lower to keep from over pressurizing the unit. All you want to do is be sure the vent is open and if you can feel air flow out the vent, you're good in that regard, but need to look for another reason for the leaking seal. HTH.

[opelenvy]

Yeah, that's all I wanted to do was see if air will flow out the valve (like it is supposed to. Well I went back out and stuck the allen back in the hole. I don't know what I was thinking the first time, but I got 1.5".
So my leak is something else. I put some silicone around the seal and stuck it back in.
I guess worst case is to buy a new bearing and new seal.

[GTJIM]

Opel made provision for leaks by putting a hole through the backing plate for the brakes at the bottom and a pressed sheet metal catcher around the bearing to guide any oil back to the inside of the backing plate so it would not get all over the brakes - guess they expected the seal to leak a bit .......

[RallyBob]

The bearing is tight, this is the second new axle seal in a year....

I take it that when you say you replaced the axle seal you mean the o-ring seal at the perimeter of the axle bearing? While that is one potential source of a leak at the axle bearing, the other is the bearing itself. It has an internal seal, and they can go bad (and leak) even if the bearing itself is not worn. If this is the case the only solution is a new bearing.

HTH,
Bob

[opelenvy]

I take it that when you say you replaced the axle seal you mean the o-ring seal at the perimeter of the axle bearing? HTH,
Bob

Yes, I was referring to the O-ring. I got some brake cleaner today. I will clean everything back up, put the wheel back on, and see if the silicone around the o-ring helps any. If it is still leaking then I will have to get a new bearing.
Hopefully I won't have to. I'll post my results here.

[kwilford]

George

You will almost certainly have to replace the bearing as Bob suggested. To do so, you also need to chisel the old retaining ring off the axles and buy a new bearing and ring (both from OGTS). Then you need to borrow a press to press the new ring on. The later ('71 on) FSM has adequate illustrations to show how.

HTH