I need to replace four subframe bushings/body mounts in the area under the front door hinges. I have tried to saturate the area with liquid wrench. In trying to unscrew the first bolt I broke the head off. Apparently these bolts are attached to some part of the frame or nut??? What does the bolt screw into and what is my next step?
Before I assume something hidden I’d just assume rust and perhaps some kind of thread locker. This might just be the kind of thing you’d rather leave to a shop. Or at the very least get your hands on good compressor and impact wrench.
The bolts either thread into a weldnut or a J-nut. When I’ve replaced these bushings it usually took an oxy/acetylene torch to heat the bolts up enough to break the rust bond between the bolts and nuts. Now that one of the bolt heads has snapped off, the only way to remove it is to weld a hex nut thru the center onto the shank of the bolt.
I have a 97 lesabre and was trying so hard to unscrew the bolt and couldnt get it to budge. Then I got smart and pulled out the tire iron type thing that my buick uses to undo the nuts for the tires/raise the jack. Loosened it right up with nearly no effort.
I had to have four of mine replaced a few years ago. The guy at the alignment shop had a heck of a time getting them out with the weldnut turning on them. They used something to hold the nut and of course air tools and a torch. You might want to consider having a shop do this.