My 1997 Tahoe has the larger 11" Drums, and as I'm trying to recall, I don't remember having what was termed the "police package" per se, but since I ordered the truck with heavy duty suspension, the towing package, tranny cooling package, the whole shebang on all drivetrain-chassis upgrade options.
Perhaps this police package option was then included in these other options?
As for the back drums, I would assume once one is fairly close with drum shoe adjustments, then backing in reverse a number of times, and applying the brakes firmly should further adjust them. That is if there is no seizure of those shoe adjusters.
Some months back when I replaced my Booster, and did another Bleed, I did pop both Drums again, removed both adjusters, dis-assembled both, wire brushed, and applied a very light coat of anti-sieze on the threads, re-assembled and re-installed them.
About the only other thing I can offer, is the possibility of air still being in the system. And the likely culprit of the cause might be the ABS Unit. I know basically squat about the ABS, but do know there are special tools made for bleeding the ABS, and as well that a code can be pulled up-cleared I think also via the ECM.
