1) Shutter Speed Dial
2) Frame Counter Mechanism, Advance Gear, and Shutter Release Button
3) Flash Shoe, Flash Contacts, and internal connecting cable to flash sync switches 14
4) Advance Lever
5) Shutter Mechanism High Speeds / Slow Speeds Control Assembly
6) Slow Speeds Mechanism
7) Rangefinder Coupling Roller
8) Viewfinder / Rangefinder Assembly
9) Rewind Mechanism
10) Self Timer Mechanism
11) Release shaft, Bulb Lever
12) Film Winding Gears / Take up Spool
13) Body Casting / Sprocket Assembly
14) Flash Sync switches
15) Shutter Drum / 2nd Curtain Release Cam Assembly
16) 2nd Curtain Roller
17) Bright Frame Selector Keying Lever
18) 1st Curtain Roller
19) Shutter Cocking Sector Gear
20) Shutter Roller Tension Spring Lock Nuts
21) Release Plate
22) Film light baffle
23) Shutter Break Mechanism
24) Light Seal Cloth
25) Back Cover / pressure Plate
26) Base Door Lock
27) Bayonet Mount
Exploded view of Leica M3 parts, and their description from my book: "Leic Design 101".
Not an easy Repair !