I am having an on going problem with the 4x4 actuator on my 2002 Blazer. This is the 6th time it failed/tore. There is no oil in vacuum lines, cable to front differential replaced, battery is not leaking acid. Other than it being a poor design, I don't know what is causing it. Any help would be greatly appreciated.

 

Where have you been getting your parts? Even cheap ones should last a few years.

 

I bought it from a Chevy dealer, Napa, Autozone, Advance Auto Parts. All seemed to be the same quality. The front differential cable seemed tight, so I replaced it as well. Can it be something in the axle?

 

Tears in the diaphragm are either due to poor quality rubber, heat, or other mechanical damage (parts/hoses rubbing on the diaphragm, etc) that is causing the failure of the seal.

A malfunction in the front axle would simply result in the diaphragm not pulling in all the way and shouldn't result in the rubber tearing. The vacuum reaching the diaphragm isn't any different regardless of whether it pulls in on the cable or not.

When the actuator is new, does it properly pull the cable in 3/4" or more? What does the diaphragm look like when it is pulled in? Is it collapsing in places that are not pleated (formed folds)?