I recently bought a well used 1979 Kubota L295DT. The rear tires (12.4-24 ag tread) are pretty rough (cracked sidewalls, chunks missing, etc...) and have tubes that are filled with brine according to the previous owner. The left rear has not only developed a leak, but the valve stem got pulled into the tire as I guess the tube and/or the tire itself shifted. What are my options for repair or replacement here? I know that I can't just pull them off myself since the tire weighs hundreds of pounds filled with brine. I'd hate to see what a mobile repair guy with a crane charges In any event, once I get them off should I just re-tube them and leave the old tires be? Should I replace them with tubeless tires, etc...? If I do replace them with tubeless tires that might a challenge as the hole for the valve stem looks kind of hogged out either due to corrosion or because it was deliberately done. I'm not sure that a new valve stem could be put in and sealed properly?