Rear axle question leaking issues by seal

[Navy_chief]

Guys,
I have replaced the rear seals and I still have a small leak on the drivers side?

The metal axle flange gasket is that the only gasket for the axle by the hub?

Also how full are the axle tubes suppose to be with gear oil?

When I pulled out the axle to see if there was something wrong with the seal the fluid level was just below the axle seal?

As always I appreciate any assistance.
Matt

 

[gr8scott]

how full are the axle tubes suppose to be with gear oil?

There shouldn't be any gear oil in the axle tubes. You fill the differential to the top of the fill hole and that's it.

 

[DirtDonk]

Yeah, but there will always be some flowing out there during turns, and depending on the level of the vehicle when you filled, it could have exactly the amount the Chief described.
In fact, I would say that Ford did not bother to raise the fill-point on the center section when they went over to the tapered roller bearings in later models and used gear lube to keep the bearings cool and happy.

So I would say that under most circumstances, there is supposed to be at least a little fluid in the tubes, except when cornering hard.
Bottom line though, would be to draw a straight line between the fill hole and the bearing, and see how much you think there should be. Looks to me like it's just at the level of the tube, so fluid easily flows into it under even the slightest inclination.

Regarding the steel gasket behind the retainer, that's probably more for keeping outside gunk out, rather than inside gunk in. The inner axle seal should be keeping 100% of the gear lube inside the tube.
If you're leaking still, then there three things I can think of that are common issues.

1. The seal surface on the axle shaft is damaged, grooved or pitted. (pretty common)
2. The inner part of the seal was nicked by the axle during installation. (semi-common)
3. The surface of the housing end where the seal is pressed in is damaged slightly. (VERY common).

This last can easily happen with the old seal is being removed. Best thing for it then is to clean and dress the surface if you can, and use silicone sealer on that surface whether it looks good or not. Mine looked perfectly fine (with just the barest hint of a scratch), but it took silicone to fix my leak.

Good luck.

Paul

 

[Apogee]

There shouldn't be any gear oil in the axle tubes. You fill the differential to the top of the fill hole and that's it.

That would be a neat trick...I could see filling it to the bottom of the fill hole, but to the top sounds really difficult to me, like herding cats.

Most 9" diffs have some oil in the tubes, at least all of mine do, but how much depends largely on the rotation of the differential since that's what determines the relative postion of the fill hole. Pinion lubrication can become an issue if you rotate the pinion up and don't increase the volume of oil used, but usually only at the extremes.

 

[DirtDonk]

... like herding cats.

Hah! Loved that commercial. Funny stuff that.
But if you're really fast (and don't mind a big mess), you can probably accomplish either.

Paul

 

[first timer]

one other thing not mentioned is the axle vent tube. my seals were leaking and new seals didn't help. pulled the vent tube and the small pinhole that actually vents it was clogged. cleaned it out and haven't had a leak since. well at least there, plenty of others though!

 

[Louie76]

there is also room on each side to put 2 seals per side, the outer one i installed backwards to help keep the water/mud out