Reply to "Rust prevention from the inside out"

There have been lots of attempts. In the mid-'70s, the method was to drill the POCA- recommended drain holes in the rear rails and the bottoms of external 'horse-shoe' a-arm braces, plug them all and fill the rails to the brim with drain oil! After a few hours of soaking, pull the plugs and drain. Leave ALL the plugs out for driving, too. Other people have uses wands attached to sprayers etc. Only the first method guarantees complete coverage, though. And you don't necesarily need to use drain oil. But you do need the 3/8 or 1/2" drain holes-3 in each rail (6 total) and one in the base of each a-arm horseshoe (4 total).