I have an 04 suburban that I'm trying to put a hitch on and am having problems with. It is a curt hitch, there are 4 bolts into the frame and 2 into the bumper. The frame bolts went in with no problems, it's the bumper bolts. I can't get them in. I've tried pb blaster, wire brushing the inside as much as possible, no luck. My next steps are to run a tap through in hopes of clearing the rust out or welding it on.
Any other ideas or suggestions?

 

Its possible the thread is different then the bolt supplied, if you have a set of taps you might want to use those to identify the thread...
Though re-tapping to the bolt in hand is probably viable as long as your have sufficient thread to securely hold the bolts in place...

 

for some reason the bumper fastener threads crud up. I squirted trans fluid onto the threads and let it soak in for 24hrs and then repeated. I soaked the bolts in a jar of trans fluid for a couple days also. I hand started them and worked them in and out with a impact wrench.


get all the bolts started before tightening any up.