An 80 model 116 chassis had the first "laser cut" keys. They were the small ones and failed regularly. If you have a regular style key the ignition tumbler has probably been replaced with a workshop version (comes uncoded with key- old style key). If thats the case the door keys probably still work with the original laser cut that can be ordered through your dealer

If a new laser works the doors a coded ignition tumbler can be had in the same code.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician