1999 clk320 oxygen sensor removal
 

Located all 4, and was able to replace the one with the blue plug, located lower right side. But space is so tight. I'd appreciate any tips or manual instructions how to remove the other 3. I have the sensor removal tool, but
seems impossible to either get it on or generate enough leverage lying on my back with the car on ramps to get them loose. Is it easier with a 22mm wrench? Thanks.