Is the throttle / servo saver operating in both directions?
If you physically push the brake lever do they engage?
If, as you say, everything is installed correctly then adjusting them should make them engage.

Or are they engaging and just not stopping the truck? That could mean that they're not adjusted properly or maybe need new friction pads or maybe that you have a weak servo or defective servo saver.

One thing that I found helped the brakes on my 25 SS was going to the Ofna throttle mod. I hated the stock servo saver, it was weak and kept sticking.