Does anyone know how to fix climate control vacuum motors?
 

The problem with the climate control on the W126 bodies is the thin rubber they used in the vacuum actuators. The rubber cracks easily and thus leaks. The problem is biggest in the dual chamber actuators, but the single chamber actuator rubber can crack as well.

I tried to use electrical tape to patch the holes, but it binds the actuator.

Any ideas?

Best solution is to get a new actuator. Good enough solution is to get replacement diaphragms. Replacement diaphragms are only so good in dual chamber applications.

I don't think FastLane and PartsShop offer diaphragms so try George Murphy or a place called www.autolux.com or something like that. It's in the archives.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

Since they are cheap and last a lifetime seems like the best bet is to replace them and forget them.