im doing a truck conversion on my 4 door blazer, anyone know the best way to remove the rear side glass without having to break them out?

 

You get the appropriate tool to cut through whatever holds it in.

Since you didnt specify year/gen.. the above answer applies to all vehicles.

In your case, I'm going to assume that tool is a metal handle, end of which is an L shaped blade and the handle has a short piece of cable to which is another handle used to pull the tool through the seal.

K-Tool Windshield Removing Tool Steel Ea 70540 on eBay!

 

Sorry for my sloppy English! When I remember right there were some metal clamps holding the glass from inside, under the plastic cover of my 1992 S10 Blazer. I would put them out bevore cutting the gasket.

Nice greets! Joe