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I've got a 2007 Pontiac Torrent that I (mostly) installed a hitch on. The hitch mounts to 8 points. 6 points are existing welded in nuts.

4 of these welded nuts are causing me trouble. They've rusted so badly I can't get a bolt through them... They are in the frame, so I don't think I can remove/replace them.

Any wonderful suggestions?

starholme
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A tap/die is not the same thing as a thread chaser - while it can be used that way, you have a higher risk of cutting new threads instead of renewing old threads.

A proper thread chaser will clean up old threads with a much lower risk of cross threading. They can save threads that appear destroyed and are well worth the expense. Here is a Craftsman set that I use with great success (as of a couple years ago, still made in the USA):

Craftsman thread chaser

EDIT: Confusingly, this set is labeled as a "tap and die set" but you can see in the picture that the threads are much less aggressive than a regular tap or die.

I bet if you use some penetrating oil like PB Blaster and one of these thread restorers, those welded nuts would clean right up.

masospaghetti
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Have you tried completely drenching them in PB Blaster or a similar penetrating oil? I've seen it work wonders in the past for me.

enter image description here

I'd cover them in a layer of that, and let it sit for several hours. Odds are, it'll dissolve enough rust that you'll be able to work a bolt into it.

Lynn Crumbling
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Save for the trouble of going to the store this is a pretty easy fix.

Take one of your bolts and go to a hardware or auto parts store and ask for a tap to match. Then run the tap through the holes.

The tap should go pretty easily. If not double check that it's the right size and then work by turning it in a turn it so and then backing out just a bit.

dlu
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Taps come in different styles. A starter tap will have a taper on it, rather than being parallel. So you can let it feel its way into the rusted captive nut. Finish off with a parallel. Failing that, taper the bolt end on a grinding wheel, and work it into the nut, a bit at a time. That's a good move anyway to start a tricky-to-line-up bolt. Obviously using lubricant all the time.I'd also try some extreme heat, as in oxy-acetylene, if there's no risk of anything catching fire.

Tim
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