I've been going through an old '71 model Ford C750 truck recently for a customer getting it ready to mount a big air compressor unit on it. The Cab/chassis origionally was mounted with a fire truck bed for a local VFD. It's been setting for about 6 years so of course it needed alot of TLC. Since this was an emergency vehicle you'd think everything on it would have been "up to snuff" and everything on it taken care of with great care, especially the brakes. Finally got around to changing the front ones today and it was easy to tell someonme didn't have a clue what they were doing the last time they were changed. These things are self adjusted with a slug that goes through the center of the pad and contacts the rim. When it hits the rim it works against a wedge to adjust them out automatically. For them to adjust the slug has to hit the rim from the start and is supposed to be .005 above the pad level when fully retracted. Both sides had had old worn out slugs used and neither came even close to extending out past the thickness of the lining, one side had keeper washers in the wrong place which kept the manual adjusters from working as well as cocking the pad causing it to wear both it and the drum one sided. Seeing the shape these brakes were in really suprised as well as scared me. I'd have figured being an emergency vehicle the truck would have been taken care of to the N'th degree by someone that knew what they were doing. Looks like someone got in a bit over their head on this thing and screwed up somethig that could have caused a devistating, potentially fatal accident....Like my subject line says, if you don't know what your doing, especially with something like a vehicles brake system then leave it alone and either ask before you do or seek professional help.