Frame rust 101
Swiped from 71 Shark (Eric) in the C-3 area.
Heres where I look / what I do in my rust investigation whenever I check out a vette for someone.
1. Look all around underneath w/ flashlight, if you see swiss cheese tell the guy "nice car, see ya later," if not, proceed.
2. Check the A-arms for stress cracks and rust, they take a lot of abuse over 25-30 years.
3. Take a business card and run it along the window frame (learned from an NCRS judge), if it comes out red, the A-pillar/window frame is shot and that is a MAJOR repair. Also, check the area above the door hinges for rust - I've seen fresh paint applied right over the rust on the A-pillar before.
4. Check the rear trailing arms and the slot in the frame where they mount.
5. Check the radiator support, lots of times the rubber flap gets bunched up and water just stands and eats away at it. These I've seen 50% gone already from rust.
6. Safety check - run your hands along both frame rails, at the rear a few inches ahead of the back wheel are keyholes on each side. Stick you finger in the holes and run it around, if you feel anything sharp, the frame may have been straightened. Some people feel perfectly safe with this but I pass on it.
I feel like I'm forgetting something, if I remember any other key points I'll post them. These are just the majors, a detailed inspection is always in order.
Good luck!
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