It's called "rust"! If the threads are still there where you removed the nuts, you might try putting the nut back on and tightening it to pull the bolt loose. Put some anti-seize compound on the threads first, (not grease).
A fellow mechanic assembled new struts on a Dynasty before sending it to me for the alignment. He used anti-seize on the lower mounting bolts. His intentions were good, but when I tightened the bolts, the spindle slipped and I had to start all over again. When it happened the second and third time, I tightened the bolts so much that I snapped one in half with a hand ratchet! That's a half inch diameter bolt that I pulled apart in the middle because there was so little friction, the nut never felt like it was getting tight. With that much force, I would hope you could convince those bolts to move. You can also try banging on them with an air hammer while you have that high pressure on it from the nut. Hammer a little, then keep tightening the nut. If you run out of threads, stack some large washers under the nut.
I can't remember if the cross member can be unbolted from the body or if it's welded on. I do know Intrepid cross members can be unbolted. If you can take it off, you can set it up in a hydraulic press to push the bolts out. That will work for the spindle too.
When you replace the bolts, coat them with grease or anti-seize compound, but don't put anti-seize on the threads; the nuts won't stay tight. Spray lithium grease, (Spray White Lube from the Chrysler Parts Dept.), Is good on threads to prevent rust. Also, if you use the Mopar Rust Preventive to loosen the bolts, (this is REAL good stuff), be sure to wash it off. I tried using it on alignment adjustments so they would be free in the future, but I found that while it did indeed free up rusty bolts, moisture would follow the chemical in later causing the parts to be rusted even tighter. Again, Spray White Lube is the best thing I found to prevent rusty bolts.
Friday, April 24th, 2009 AT 2:37 AM