Overview. Actuator diaphragms dry out and crack, leading to malfunctioning HVAC flaps and troublesome vacuum leaks. This kit gives you what you need to renew every HVAC actuator in the car in one shot.
Fitment
- 1981–85 300D, 300CD, 300TD with ACC III
- 1981–83 240D with ACC III
- For earlier W123, contact us for a custom kit
Cross-reference part numbers (this kit rebuilds actuators including but not limited to):
- Center nozzle flap: Mercedes-Benz A 116 800 11 75, A1168001175, 1168001175, 116 800 11 75, 116 800 1175, 116-800-11-75, 116.800.11.75
- Main air flap and fresh air / recirculation flap: Mercedes-Benz A 123 800 11 75, A1238001175, 1238001175, 123 800 11 75, 123 800 1175, 123-800-11-75, 123.800.11.75
- Legroom flap: Mercedes-Benz A 123 800 31 75, A1238003175, 1238003175, 123 800 31 75, 123 800 3175, 123-800-31-75, 123.800.31.75
- Defroster nozzle flap: Mercedes-Benz A 123 800 22 75, A1238002275, 1238002275, 123 800 22 75, 123 800 2275, 123-800-22-75, 123.800.22.75; A 123 800 32 75, A1238003275, 1238003275, 123 800 32 75, 123 800 3275, 123-800-32-75, 123.800.32.75
Lock plate / push nut included (6): Mercedes-Benz 912010-004002, 912010004002, N912010004002, N 912010 004002, 912010 004002
What’s included (one each)
- Center nozzle flap actuator (116 800 11 75): deep single-stage diaphragm
- Main air flap actuator (123 800 11 75): deep single-stage diaphragm
- Legroom flap actuator (123 800 31 75): deep single-stage diaphragm
- Fresh air / recirculation flap actuator (123 800 11 75): deep single-stage diaphragm
- Defroster nozzle flap actuator (123 800 22 75 / 123 800 32 75): dual-stage cartridge, eyelet style
- 6 × Mercedes-Benz lock plate / push nut (912010-004002), not sold separately
Installation
See the video instructions.
Rebuild tips
- Old actuator plastic can be brittle: open housings with 4 thin plastic strips (an old credit card works)
- Clean dust and debris from the housing; don’t use lubricants except dimethicone (lemon Pledge)
- Stretch the diaphragm rim by hand just before closing the housing
- Test with a hand vacuum pump (e.g. Mityvac)


