Coca Cola contains phosphoric acid which is the active ingredant in the rust disolvers/converters. Like Navel Jelly. Makes you feel good about drinking that Coke dosnt it? I have a '49 Chevy I had to do the same thing with. I got all the loose rust off with the wire wheel on my grinder. Then I put Navel Jelly on it and let it sit. You can get Navel Jelly at Home Depot. Let it sit over night is best, then with soap and water I scrubed the heck out of it with a stainless steel scrub pad. then painted it with Zero Rust. <a href="http://www.zerorust.com" target="_blank">www.zerorust.com</a> To me its easier and safer then POR-15 which I have use and was nervious about it the whole time. Plus it can be sprayed were POR-15 cant. Hope this helps!