1979 300sd (w116)

Have an ATF leak at the pan drain bolt.
How many washers are used to secure the line to the pan.

When I pulled the line 2 washers came off, one with the bolt and the other one dropped to the floor.

I placed only one washer back on the line (on the bolt) and I'm now getting an ATF leak in that area.

I remember being puzzled that there were two washers and so I found a schematic that only showed one washer being used in that area.

Please advise

Update:
Uses two washers, one on the drain bolt and the other is compressed on the other side which makes contact with the drain pan. Leak is gone. Only thing I could not find was the torque spec for the bolt.