Overview. Dried-out diaphragms stop the HVAC flaps from moving and cause vacuum leaks. Choose the kit for your car’s generation to rebuild every actuator at once.
Gen I vs Gen II. Both kits are the same price. The difference is in the dual-stage cartridges: in the Gen I kit, one of the three is the eyelet style; in the Gen II kit, all three are the clip (clasp) style.
Cross-reference part numbers (this kit rebuilds these Mercedes actuators):
- Main air flap, right (Gen I): Mercedes-Benz A 000 800 37 75, A0008003775, 0008003775, 000 800 37 75, 000 800 3775, 000-800-37-75, 000.800.37.75
- Main air flap, right (Gen II): Mercedes-Benz A 000 800 57 75, A0008005775, 0008005775, 000 800 57 75, 000 800 5775, 000-800-57-75, 000.800.57.75
- Main air flap, left: Mercedes-Benz A 000 800 58 75, A0008005875, 0008005875, 000 800 58 75, 000 800 5875, 000-800-58-75, 000.800.58.75
- Defroster nozzle flap: Mercedes-Benz A 000 800 43 75, A0008004375, 0008004375, 000 800 43 75, 000 800 4375, 000-800-43-75, 000.800.43.75
- Center nozzle hot air flap: Mercedes-Benz A 000 800 67 75, A0008006775, 0008006775, 000 800 67 75, 000 800 6775, 000-800-67-75, 000.800.67.75
- Air scoop flap: Mercedes-Benz A 000 800 40 75, A0008004075, 0008004075, 000 800 40 75, 000 800 4075, 000-800-40-75, 000.800.40.75
Also rebuilds (alternate W126 dual-stage numbers):
- Main air flap (clip style): Mercedes-Benz A 000 800 60 75, A0008006075, 0008006075, 000 800 60 75, 000 800 6075, 000-800-60-75, 000.800.60.75
- Dual-stage actuator (eyelet style): Mercedes-Benz A 000 800 36 75, A0008003675, 0008003675, 000 800 36 75, 000 800 3675, 000-800-36-75, 000.800.36.75
What’s included
| Actuator | OE number | Gen I (1981–85) | Gen II (1986–91) |
|---|---|---|---|
| Main air flap, right | 000 800 37 75 (Gen I, dual-stage eyelet) / 000 800 57 75 (Gen II, dual-stage clip) | Yes | Yes |
| Main air flap, left | 000 800 58 75 (dual-stage clip) | Yes | Yes |
| Defroster nozzle flap | 000 800 43 75 (dual-stage clip) | Yes | Yes |
| Center nozzle hot air flap | 000 800 67 75 (deep single-stage) | Yes | Yes |
| Footwell flap | 000 800 42 75 (Gen I) / 126 800 14 75 (Gen II) | Not included | Not included |
| Air scoop flap | 000 800 40 75 (deep single-stage) | Yes | Yes |
The footwell flap actuator 000 800 4275 is still available new from MBZ and is not included in either kit.
- Gen I kit (1981–85): 1 dual-stage eyelet cartridge, 2 dual-stage clip cartridges, 2 deep single-stage diaphragms
- Gen II kit (1986–91): 3 dual-stage clip cartridges, 2 deep single-stage diaphragms
Before you order: check your dual-stage actuators. We strongly recommend confirming whether each dual-stage actuator uses an eyelet or a clip linkage, especially the main air flaps. Your car’s generation is a guide, but cars vary. If unsure, get behind the dash with a flashlight and check before ordering.
Installation
Watch the video instructions before starting.
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)
