Lack Luster Brakes

Have you tried manually adjusting all four corners?

So when I installed the booster a year or two ago I did. I may have done it last year as well (have to look at the maintenance log). When thinking in the shower this morning I thought the easiest place to start was at all the wheels to see where they are adjusted at, remove drums and wheels to see if that adjuster is working properly and insure that the brakes were assembled properly. From there adjust the brakes and put on the ground and try another trial drive and see what happens.