brake master cylinder leak

[piddler]

There is a small hole at the bottom of the base of the master cylinder that has been dripping oil. We noticed the oil on the garage floor and traced it to the aforementioned leak. The oil smells a little like brake fluid but does not have a strong smell. It drips while the car is sitting.

Is this telling me I have a problem with the master cylinder or the booster?

[teahead]

most likely. 

Losing any noticeable amt of brake fluid?

[piddler]

We don't drive the car a lot but the reservoir is nearly full.

[Charles 230SL]

Is this telling me I have a problem with the master cylinder or the booster?

Hi Piddler, I had this problem several years ago with my 230's master cylinder. 
Your master cylinder is leaking fluid at the plunger-end where it mounts to the brake booster. The fluid could eventually find it's way into your booster and ruin the front diaphragm.  The master cylinder will need to be either replaced or rebuilt. There's a number of threads and a wealth of info on this forum about removing and replacing the master cylinder. take care, charles

https://www.sl113.org/forums/index.php?topic=29116.msg210549#msg210549