Outer Limits 4x4 Board

Hi all, a mate of mine has an MK Patrol, it has an SD-33 NA diesel in it. He rang me today to say he has an oil leak out of the back of the alternator, I am going into his place Tuesday to have a look at it for him, but I dont know alot about diesels and their workings. His ALT is still charging fully so there is no problems there not yet any way. My questions are-

1. What is the reason for the oil system on the ALT?
2. Can I disconnect the oil system to the ALT?
3. Can I convert another ALT to fit onto his motor and if yes what type?

Any other info that anyone could give me would be a great help.

its the vacuum pump on the back of the alt. should be easy rebuild. might be just a hose clamp, banjo bolt,etc come loose. will not affect the charging on your alt, just your brakes if it totally shits itself.

Prob just the oil seal that runs on the shaft, sits in the back of the alt housing. Will eventually leak oil onto the slip rings and start playing up.