Minor surface rust is not an issue. Rust that comes off in flakes IS.
Where is the frame rusty? Can you get some pics? The most common area for rust, and damage from rust on these cars is just in front of the rear tires, on the frame....most accurately IN the frame. Where the rear trailing arms fit up into the frame is a major rust trap.
Some pics of your rust would help determine how bad it is, or if it's nothing to be concerned about.
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Joel Adams
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