Dual-Stage diaphragm cartridge for Behr defrost and fresh air flap actuators in R107, W116, W126, W123 and others. Perhaps the most overlooked cause of poor a/c system performance.
 
Dual-stage flap actuators (three-position actuators with two vacuum chambers) are no longer available for W123 and many other models. While single-stage actuators can be easily renewed by changing the diaphragm, dual-stage actuators have a captive diaphragm assembly sandwiched between two drive pistons and a spring in a special press fit cartridge assembly.
 
Here we offer the entire cartridge, allowing you to rebuild dual-stage actuators when the diaphragms dry out and crack.
 
Use care when removing and opening actuators, as old plastic may be brittle. We recommend using 4 thin strips of plastic from an old credit card to open the assemblies (see the video below). You will need a vacuum pump / Mighty-Vac to test, and may need to move linkage over by drilling out a rivet. We include hardware to re-attach linkage. Stretch diaphragm by hand immediately prior to closing housing.
 
Please see our video tutorial for more info.