I have a 1997 2-Door Chevy Blazer Base with a 4.3L engine. The issue I am having is I am getting a clunk/knocking noise when going over bumps from the center of the vehicle. It happens mostly when cold or wet outside. If it it warm and dry the noise almost completely goes away unless I hit a really big bump. I have narrowed it down the be coming from the torsion bar support brace area. I have spent hours looking for anything underneath that could be making this noise and everything feels secure and tight. I recently changed the torsion cross member / support brace bushings and no change. I also backed some hub grease around the hex area of the keys where the slip of the end hex of the torsion bars and once again no change. I did notice when I chance the torsion mounts and had the bars unloaded the keys had some plays and up and down slop. I am not sure if this is normal? The torsion bars still felt pretty snug in their placement when unloaded. I also recently replaced the front ball joints and most of the front end steering and suspension components and also no change in helping the noise.

I also wanted to add that when I go over an large hump or incline with one side of the front the vehicle I get a pop sound from the same middle area. Is it possible for the keys to be warn? The vehicle has almost 145,000 miles and serves as my spare vehicle and toy. I am not looking to spend a ton of money but would sure love to diagnose and repair this issue. I am thinking someone out there with an S10, blazer or a torsion bar setup vehicle has had to seen or heard of this. Thanks for looking. Also my rear away bar links are dry rotted the bushing but don't have any play or movement when I yank in them.

 

It's most likely the rubber bushings on the t-bar crossmember bolts .. Did you replace the bushings on the studs that hold the cross member to the frame also ? Or just the ones that look like supped up sway bar bushings and it is normal for the keys to have a little play on the bars hope this helps