Drain Hole Under Brake Booster

[beachbear]

While cleaning my engine bay, I came across a hole that seemed odd & out place. Looking through the forum I came across a post from 2003 that seems to describe the same thing. But there were no attached photos. There were links to an ïndex 375, but that goes to a dead end. Here is the hole I'm trying to identify. There was a rotten grommet laying on top of it, but it didn't belong there. Is it really a drain? Should it have a rubber plug?

[Pawel66]

There were several threads on this hole. If I remember correctly this hole leads to an empty space between the metal sheets and the conclusion was: plug it.

Try search "drain holes" or "drain points" to check this.

[Shvegel]

There is another on the other side of your car. Is it plugged?

[beachbear]

With your question, I unclamped the wire harness that runs across where that hole would be. There is a hole, plugged with a rotten plug. My clean up has not made it as far as that part of the engine bay. I found a 10mm plug at AuthenticClassics that should work to plug both of these holes. Thanks for your help.

[Charles 230SL]

There is another on the other side of your car. Is it plugged?

Shvegel, are you talking about the plug under the wiper motor? I've never even seen the plug under the brake booster - until just now when I searched with a flashlight. thanks, charles

[Shvegel]

Charles, 
It in the exact same location on the other side buried under the wiring harness.

beachbear,
Thanks for checking that.  Now I know there are supposed to be plugs in the holes and where the strap for the harness is located.

[beachbear]

Charles, that is a GREAT picture of the plug under the brake booster. Thanks!

[beachbear]

BTW, looking at the hole underneath the wiper motor, it, the one under the brake booster and the one on the right side, under the wiring harness (on my LHD 280) appear to be the same size.

[Harry]

I just redid my engine compartment and I didn't find this plug (1966 230SL).  I did find that there is a drain "hole", if you will, that actually is an opening in the sheet metal in this area that will permit water to drain down into the wheel well.  You can also see that from within the wheel well.  It is where the sheet metal fits against the frame on the horizontal area.

Harry