Having same problem and we decided to flip tub on it's side. Leave the bolt in and clean area around the base. Next hold bolt with channel locks and center it while pulling it firmly towards you. Next weld it tight. Now you can remove the bolt and you didn't have to cut into the channels under your tub. Hope this helps.
Smokedog - Brandon, MS
84' CJ7 Renegade - Tungsten grey metallic paint, 388ci Chevy, 700r4, D300, SOA lift with YJ springs, 1" body lift, Bilstein 5150 shocks, Currie Rock Crawler Shackles, Trussed Ford 9 Rear w/ 4:56 gears, Detroit lockers, Dana 44 front, full poison spyder cage and lots of chrome and stainless.