the phrase is ............... go do one 
you make ti look so easy 
)
Depends how the other end is machined. Will it will be set up to connect with the other bmw special tool, which may not be a socket
Ok, leaking rear input seal on your bevel drive.
If your doing this job, you know enough to be able to take off the rear bevel .
Here's the seal thats leaking. it's hidden behind the securing nut, you can just see it
As well as replacing the seal, you'll also need the inner seal ring.
This can have a groove worn on it's surface, as it spins inside the seal at shaft speed. Only a couple of pounds, so makes sense to replace it regardless while your doing the job.
Here's the ring from the leaking bevel.
And here's a new ring.
Put the bevel in a vice. I screw in two old wheel studs in the output wheel flange, and position the bevel in such a way that they'll stop the internals rotating as i undo the securing nut on the input shaft.
You'll need a deep 36mm socket to undo the input bevel securing nut. And it's tight - 200 nm.
I have a big feck-off cordless electric impact gun. Max Torque 400 Ib ft
Undo the nut - bang whizz.
Now you have to undo the securing ring. It'll need a special tool.
I made my own, and then welded a large nut on the end of the tube because this ring is also done up tight - 160 nm. It's not made to look pretty, it has a job to do.
This is inserted inside, impact gun attached , bang whizz, and it's off. You can use some heat on it when removing the nut and ring if you need to. .
You should now have the nut, seal ring, and securing ring. The seal is in the securing ring. All the old items in the picture below.
New seal and ring
Remove the old seal from the securing ring. You'll notice a lip on the securing ring, the seal only goes in one way, from the rear.
The front of the ring
The rear of the ring.
Now carefully insert the seal into the rear. Picture view looking at the rear.
And from the front.
Now carefully screw the ring back into the bevel unit. Torque setting 160 NM
And then slide the ring over the input shaft and into the seal. The picture shows the ring after it's been pushed into the seal
.
And then screw the input bevel nut back on - torque200 Nm.
And it should look like this when it's finished
Check it all turns by hand before replacing the bevel back on the bike.
