8 3/4 leaking diff fluid into Brakes

Any suggestions on what to try next???

Just a couple thoughts here.

Did the spring get knocked off during installation?

(When I put them in, I pack a little grease on the spring side.)

Did you cover the splines on the axle when installing it?

(The splines can actually nick the rubber around the axle allowing for a leak. It does require pulling the pig in order to remove what is over the splines.)

And don't let the axle 'hang' putting upward pressure on the seal, slide it in as far as possible leaving it a bit shy so the pig can be put back in.

One other thing of note, is sometimes there can be a small groove worn into the axle where the seal rides allowing for a looser fit, hence possible leak.