Starter motor foot button

[Steve Lane]

Thank you for your help, it is really appreciated! The starter appears to be in three parts; the starter button along with a top and bottom section to the starter motor. The top part of the motor is shown on the photo and has a black casing with the main live connection terminal, this has 2 long bolts holding it in place. Then there is a silver part to the starter at the bottom which is held in place by three bolts in the crank casing. Both these parts are linked by a gear visible through a small gap. 

Do I need to remove BOTH parts of the starter motor to get to the switch terminals? 
If I remove them will there be any springs, oil etc when they are removed?

I believe the starter motor has a drive key.