[Ironangel]

Were you able to collapse the slack adjuster? There's usually a thin plate at the top of the adjuster star wheel that is part of the auto-adjust mechanism. You have to push that thin plate off the star wheel to be able turn it. As long as that plate rests against the star the star wheel will only turn one direction and that direction will expand and not collapse the brake shoes. If your dealing with an unmolested brake assembly, you will be able to turn the star up and not down. The manuals indicate that you must push in on the plate with a screw driver while using the brake adjuster tool to turn the star wheel down to collapse the brake shoes. With all of that said, often over time brake dust and crud has gathered and stacked up on the exposed threads of the adjuster making it difficult if not impossible to turn the star wheel. That's where a can of brake clean comes in real handy to blast the threads on the adjuster clean before you foul the star adjuster threads into the collet. Might consider buying one of these... https://www.classicparts.com/1972-Sh...ctinfo/04-030/ If you use UN4GVN's method make sure you only work one side at a time, otherwise your going to be asking for pics on how to reassemble the mess. If the 3/4 ton C/20 brake shoes are like the 1/2 ton versions, pay close attention to the locations of the brake shoes. One shoe has a smaller lining than the other and will locate either fore or aft the axle housing. Here's a thread with some pics and lots of good info, the third pic down the thread a bit shows that pesky plate that holds the star adjuster wheel from turning backwards. http://67-72chevytrucks.com/vboard/s...d.php?t=443837