This is the liftgate hinge from my 41 woodie. It was rusted shut and now operates as it should after soaking overnight in generic Evaporust from Rust911.com. I've also used the same stuff from
http://rustdepot.com/rustremover/rustremover.htm but it is more expensive. I like the generic in that it is way cheaper and comes as a concentrate for $3.72/gallon mixed vs $30/gallon for Evaporust. It can be mixed stronger than Evaporust so it works faster as well. I also rescued the hinge on a rusted shut 36 glove box the same way. I can't think of another product to fix a rusted shut folded over type hinge. It dissolves the rust and leaves no residue.