Definitely drain and replace that gear oil.
The axle seals may be hard to get out. I had to take a long wooden pole and knock mine out from the inside (using center section opening). That is the easiest way.
To remove your axle bearings, 1st drill the spacer collar almost all the way thru (without getting into the axle). Then pop them across the drilled hole with a chisel. They will pop open and fall down the axle to the ground. Then press off the bearing.
Clean the area on the axle where the new bearing will go and where the seal rides with a scrotch brite pad.
I found the best way to get the proper parts is to carry your old ones in to the parts store you use. Ford 9" axle bearings and seals are common parts and should be in stock anywhere you go.
The gaskets are just one per side (IIRC), and it goes between the brake housing back plate and axle housing tube end. I made mine out of flat sheet of gasket material. They are to keep out moisture and dust, not hold in gear oil or anything like that. You use a thin spread of silicone as well.
Last edited by cold_beer839; 11-26-2010 at 06:15 PM.